L. Reuteri For Hair Loss: A Complete Review

Lactobacillus reuteri (l. reuteri) can raise testosterone, improve vitamin D synthesis, and increase hair quality (in rats). Once found in 40% of human guts, this bacteria is now only present in a small fraction of people. So if we supplement with l. reuteri, will we experience hair regrowth? This article uncovers the science and reveals why not all l. reuteri species are created equally.

Written and reviewed by:
Rob English, Medical Editor

L. Reuteri: Can This Bacteria Protect Against Hair Loss?

Every month, new evidence emerges that our microbiome — or the trillions of microbes crawling inside and around us — affects every aspect of our health — from our immunity to our nutrient metabolism and maybe even our predisposition to hair loss.

But which microorganisms inside our microbiome influence which functions? And more importantly, are there any bacterial strains that might help us prevent or even reverse pattern hair loss?

While the research is still in its infancy, we’re getting closer to answers… and at least one bacterial strain is showing promise. It’s called Lactobacillus reuteri (l. reuteri), and studies now demonstrate that l. reuteri colonization may help prevent hair thinning, promote faster hair growth, encourage hair follicle development, and even increase the number of our hairs in the anagen (growth) stage of the hair cycle.

This article uncovers why. We’ll start with what l. reuteri is, and then uncover how l. reuteri is connected to hair loss. Then we’ll reveal how l. reuteri‘s absence in our modern guts may help explain why men’s testosterone levels are 22% lower today than they were thirty years ago. Finally, we’ll dive into the research associating l. reuteri with decreased systemic inflammation, improved T cell migration, increased serum vitamin D, and even better hair quality.

We’ll also uncover why we should exercise caution about reintroducing l. reuteri into our guts — at least through supplementation. While there’s compelling evidence that l. reuteri may improve hair quality and decrease inflammation… this is a bacteria with a lot of different strains, and unfortunately, not all strains are created equal…

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Our Microbiome & Our Health

Right now, thousands of different microorganism species – bacteria, fungi, viruses, and parasites — are crawling your skin and your digestive tract. In fact, we harbor at least as many non-human cells as we do human cells. And these non-human cells that live inside and on us are what’s known as our microbiome — the collection of billions of microorganisms feeding off our cellular debris, undigested foods, and even our living tissues.

We can break down these organisms into one of two categories:

  1. Pathogenic — microorganisms that harm our bodies. For example — the bacteria streptococcus pyogenes — which causes strep throat.
  2. Commensal — the microorganisms that neither cause infection nor harm our bodies… and might even be helpful.

For long-term readers, this isn’t new information. I’ve written extensively about the microbiome-hair loss connection — and most recently, how a bacteria known as p. acnes – which is both commensal and pathogenic depending on which part of our bodies it colonizes – may be implicated in the development of both acne and hair loss.

But this article’s focus isn’t on p. acnes, it’s on l. reuteri. And here’s the good news: unlike p. acnes, research shows that l. reuteri is only commensal (meaning harmless), and that it may benefit our health and our hair in several different ways.

What Is L. Reuteri?

Lactobacillus Reuteri (L. Reuteri) is a bacteria found primarily in the digestive tracts of mammals — including humans. L. reuteri can also colonize certain fermented foods — like sourdough. And in normal circumstances, l. reuteri is passed from mothers to infants during breastfeeding — where it colonizes our intestines while we’re young and then remains in our guts throughout adulthood… so long as a disease or antibiotics don’t wipe them out.

The research on l. reuteri is overwhelmingly positive. And before we get to the specifics on hair health, here are just a few highlights:

  1. L. reuteri produces antimicrobial chemicals that help stave off pathogenic bacterial overgrowths in our guts
  2. Rats fed L. reuteri through drinking water experience increased healing from wounds (healing in half the time versus controls)
  3. In humans, L. reuteri supplementation reduces breath test measurements of H. Pylori — a bacteria associated with stomach ulcers and cancer — by ~20%.
  4. In rats, L. reuteri supplementation reduces insulin resistance, decreases oxidative stress, and helps reverse fatty liver disease.

So what about hair health? Can supplementing with lactobacillus reuteri improve our predisposition to pattern hair loss — or improve our speed of hair growth or even hair quality? In 2013, researcher set out to answer these questions.

L. Reuteri‘s Effects On Hair Growth And Hair Quality

A 2013 research team wanted to test whether supplementing with commensal bacteria — like l. reuteri — might improve someone’s physical appearance — ie: the quality of their skin and hair. So they conducted a series of tests on rats.

Test #1: Probiotics & Their Impact On Skin Thickness, Subcutaneous Fat, Hair Follicle Development, And Hair Quality

The first test compared young rats (20-24 weeks old) fed a standard diet to young rats fed a probiotic-rich diet through yogurt supplementation. Note: this test didn’t control for lactobacillus reuteri. Rather, the test catered more toward several lactobacillus species’ effects on fertility benchmarks — specifically, hair and skin quality.

Even still, the results were impressive.

After 20-24 weeks, the rats fed a probiotic-rich diet saw a 50% increase in skin thickness — with much of that increase coming from subcutaneous fat. And within that subcutaneous fat, the probiotic-fed male rats expressed an average of 12 hair follicles to every control group rat’s hair follicle (a 1,200% increase).


And interestingly, 74% of the hairs in probiotic-fed rats were found to be in an anagen (growth) phase. And the control group? Quite the opposite. In fact, 64% of rats in the control group were found to have telogen dominance — a condition where at least 50% of the hair follicles on the rats were in a “resting” (read: no growth) stage of the hair cycle.

Unsurprisingly, these micro-level results carried over into hair quality. Rats fed the probiotics had significantly shinier hair — a quality in rats which signals peak health and fertility.

The Problem With The Test: Confounding Variables Inside The Yogurt

The results all sounds promising, but there was a confounding factor inside the test…

The yogurt that was used to feed the probiotic group also contained other vitamins and nutrients — like vitamin D. And just like the pumpkin seed oil-hair loss study, if researchers don’t control for other vitamins and nutrients that might also contribute to hair growth, we’ll never know if the hair-promoting effects of the probiotic group were due to the actual bacterial species inside the yogurt… or the nutrients inside the yogurt itself.

So came a second test, and the selection of l. reuteri for a new test group.

Test #2: L. Reuteri And Its Effects On Skin Thickness, Hair Growth, Anagen (Growth) Follicle Phases, And Hair Quality

The researchers chose to redo the experiment, but this time, instead of using yogurt (which contained other adjunct nutrients and vitamins), they decided to feed both rat groups the exact same food… but for the test group, they would also add a bacterial species into their drinking water. And the selected bacterial species to represent all lactobacillusL. reuteri.

Here’s the fascinating thing: despite this test version now controlling for the same vitamins and minerals — which undoubtedly affected hair follicle development in the young rats — the test results for the L. reuteri-fed group were nearly identical to the yogurt-fed group.

L. Reuteri Increases Skin Thickness, The Percent Of Anagen Hairs, And Hair Shininess

That’s right. Just by introducing this single bacterial species, male l. reuteri-fed rats experienced a 100% increase in dermal (skin) thickness, a 106% increase in anagen hair follicle counts, increased rates of hair regrowth after shaving, and the same increases to hair shine as the probiotic-fed mice from the previous experiment.

l reuteri hair shine



So how can something as simple as a commensal bacteria — like l. reuteri — increase hair shine and hair follicle count so significantly?

There’s no straightforward answer. But these researchers attributed l. reuteri‘s hair-promoting effects to the bacteria’s impacts on certain signaling proteins… Specifically, an anti-inflammatory cytokine called Interleukin-10 (IL-10).

L. Reuteri Improves Hair Quality By Increasing Anti-Inflammatory Cytokines

The Cytokine-Chronic Inflammation-Hair Loss Connection

Cytokines are small signaling proteins released by our immune cells. And once released, these cytokines attach themselves to cell receptors and start to manipulate the behavior of those cells — telling tissues to induce inflammation, stop inflammation, or even begin cell growth.

Cytokines are best-known for their role in the inflammatory process — and we can break most cytokines down into two categories: 1) anti-inflammatory (reducing inflammation), and 2) pro-inflammatory (encouraging inflammation).

Many disease states — and possibly even pattern hair loss — are the result of long-standing, systemic, chronic inflammation. And interestingly, “chronically inflamed” sites of our body tend to have an imbalance of cytokines: too many pro-inflammatory cytokines are active, and too few anti-inflammatory cytokines are active.

Interleukin-10 (IL-10) is one of these anti-inflammatory cytokines that need to be active to help regulate healing processes, improve hair growth, and even prevent chronic systemic inflammation. And unsurprisingly, chronic inflammation of our scalps is a precursor to pattern hair loss.

Long story short: if we want to prevent (or even reverse) pattern hair loss, it’s in our best interest to balance our anti-inflammatory and pro-inflammatory cytokines in our skin, and thereby reduce chronic inflammation and slow (or stop) hair thinning.

L. Reuteri Decreases Skin Inflammation By Increasing Anti-Inflammatory Cytokines (IL-10)

Tor reasons not entirely understood, when the bacteria l. reuteri colonizes our guts, it’s able to increase the expression of IL-10 in the skin. And as a result, l. reuteri is able to downregulate pro-inflammatory skin cytokines — specifically, IL-17.

And as a result, IL-10 helps regulate sebum production, increase the number of hairs in anagen (growth) phases, and possibly even increase the density and thickness of subcutaneous fat — the same fat that act as a cushion for our hair follicles.

The end-result: shinier, healthier, faster growing hair. In fact, it’s the interaction between l. reuteri and IL-10 that researchers attribute to its pro-hair effects — at least in rats.

But What About Humans? Does L. Reuteri Increase Hair Growth In Humans?

We don’t yet know. There aren’t yet enough studies on humans to determine whether l. reuteri will help us slow, stop, or reverse pattern hair loss. And unfortunately — when it comes to reversing pattern hair loss — rat studies rarely (if ever) translate to humans.

But there’s good news! Of all the l. reuteri studies I’ve reviewed, the results for rats and humans shows the same directional results. In other words, in all cases I’ve found, l. reuteri supplementation in humans leads to the same directional results as l. reuteri supplementation in mice (for example, the upregulation of IL-10, changes to skin pH levels, and even the bacteria’s anti-inflammatory, antimicrobial effects).

So at the very least, introducing l. reuteri should have significant positive effect on human health — and potentially our hair health.

And even better — there’s evidence that l. reuteri might improve the conditions that often precede pattern hair loss. In fact, taking all the research into context, l. reuteri supplementation in humans might be critical to promoting longevity, decreasing inflammation, increasing vitamin absorption, balancing our hormones, maintaining our hair health, and even living with less stress and anxiety.

Here’s why.

L. Reuteri, Serum Vitamin D, And Hair Loss

When it comes to the causes of pattern hair loss, most people never suspect a vitamin D deficiency. Unfortunately, this assumption — that vitamin D has no impact on hair growth — is wrong. We’ve even seen this with some readers — like Jared — who only saw significant hairline regrowth after discovering he had a severe vitamin D deficiency, and then beginning to mega-dose vitamin D (alongside the mechanical stimulation exercises, and other things):

Natural hairline regrowth

I’ve also written extensively about the importance of vitamin D levels for hair health, and how 40% of Americans have a severe vitamin D deficiency. The bottom line is this: if we want to improve our hormonal health and decrease our risk of calcification, fibrosis, and the other myriad conditions that precede hair loss — we want to maintain optimum vitamin D levels.

Fortunately, the bacteria l. reuteri can help us increase serum vitamin D3.

L. Reuteri Supplementation Increases Serum Vitamin D By 25.5%

Human studies show that over a nine-week period, l. reuteri supplementation in humans increases serum vitamin D levels by 25.5% — and likely due to the bacteria’s ability to improve cholesterol synthesis (which is required for vitamin D absorption), and in doing so, even lower cholesterol levels in the human subjects.

And interestingly, this increase in serum vitamin D and improved cholesterol synthesis might explain another benefit to l. reuteri supplementation… It improves the hormone profiles of both men and women, and has an incredibly powerful effect on testosterone levels.

L. Reuteri, Testosterone, And Hair Loss

While conventional dogma preaches that testosterone and DHT are the main causes of pattern hair loss, when we look more granularly at the studies doctors reference to support these claims, they begin to fall apart.

For instance, only some forms of DHT are associated with hair loss. Other forms of DHT are protective against hair loss. And there’s little to no correlation between testosterone levels and pattern hair thinning. In fact, if anything, as testosterone levels decline with age, the incidence of pattern hair loss increases.

And to top it off — in young men, evidence suggests that an imbalance of testosterone:estrogen — specifically, high estrogen levels, are associated with hair thinning rather than high testosterone.

The net: young men who don’t suffer from hair loss have high testosterone and low estrogen. Young men who are balding have low testosterone and high estrogen. And if we want to protect ourselves from pattern thinning, it might be in our best interest to optimize our own hormonal profile, and start increasing testosterone naturally.

Fortunately, l. reuteri can do this for us. And beyond the fact that optimal vitamin D levels are associated with higher testosterone in menl. reuteri likely works through several different mechanisms to improve our testosterone function — and even our testicular weight.

Lactobacillus Reuteri Increases Testosterone And Testicular Weight

In maturing rats, the ingestion of l. reuteri over one year increased testicular weight nearly 40% versus control groups. In fact, older rats fed l. reuteri also expressed as good (and sometimes better) hormonal profiles than much younger rats!

And all this with just the introduction of one bacterial strain. Seriously. Just look at those testicles.

l reuteri testosterone


And what explains how l. reuteri can exert such testosterone-boosting, testicle-boosting effects?

Interestingly, researchers believe — again — that it’s because l. reuteri increases the anti-inflammatory cytokine IL-10, and in doing so, decreases the pro-inflammatory cytokine IL-17 — the same cytokine which has been shown to suppress hair growth.

In fact, researchers observed the same testicular-increasing effects of l. reuteri when they administered an IL-17 antibody. And what does that suggest? A strong relationship between l. reuteri’s effects on skin, hair, and testicular quality… all as a result of increasing IL-10, and decreasing IL-17.

L. Reuteri Is No Longer Prevalent In Most Humans’ Guts… Which May Help Explain Why Men’s Testosterone Levels Today Are Plummeting

Lactobacillus reuteri was once a common human gut bacteria. In the 1960’s, it was estimated that 30-40% of us had l. reuteri crawling around our microbiome. Today, l. reuteri is found in just 10-20% of humans.

Over that same period, studies have shown that men’s serum testosterone levels have declined dramatically. In fact, when controlling for age, men’s testosterone levels today are 22% lower than they were thirty years ago.

A lot of this is driven by changes to diet, lifestyle, and stress levels. But it’s not implausible that our gut bacteria — and specifically, the absence of l. reuteri — might explain part of this decline.

L. Reuteri Increases Anti-Inflammatory T Cells

What Are T Cells?

T cells (Tregs) are immune cells that help regulate our immune functionality. Our immune system normally attacks foreign bacteria, fungi, and viruses to prevent infection and keep us healthy. But Tregs also make us “tolerant” to resident (commensal) microorganisms. In other words, they help decide what our immune system should fight, and what it should leave alone.

If our T cells (Tregs) aren’t functioning properly — or if we don’t have enough Tregs — we open up the doors to developing autoimmune diseases — whereby our immune system confuses our own cells as foreign pathogens, and begins to attack them. The end-result: diseases like hypothyroidism or alopecia areata (patchy hair loss of the scalp).

How Are T Cells, L. Reuteri, And Hair Health Connected?

Tregs accumulate in the skin soon after birth, where they then localize to hair follicles. For years, this process was thought to be genetically determined — with the idea that your “genes” are what determine how many T cells localize to hair follicles, and thereby encourage healthy hair growth and hair follicle proliferation.

Then a 2017 breakthrough study revealed that this dogma was wrong. In fact, T cell migration isn’t exclusively genetically determined… it’s largely determined by our microbiome: our gut and skin bacteria. The study showed that our commensal microbes encourage T cell migration to hair follicle sites — and that these microbes might even be critical to hair follicle development.

In the study, newborns who were microbe-free had reduced skin T cells, whereas newborns who were born with commensal microbes had abundant skin T cells in their hair follicles — which correlate with better hair growth.

And are there any independent studies exploring which bacteria species help increase T cell migration? Yes. And unsurprisingly, l. reuteri is one of them.

L. Reuteri Increases Anti-Inflammatory T Cells

In a study on thyroid health and beneficial bacteria, mice fed lactobacillus reuteri showed a significant increase anti-inflammatory T cells.

And what coincided with that increase in T cells? An increase in thyroid size, an increase in serum T4 levels (a hormone used to measure thyroid activity), decreased fatigue, and according to the researchers, a more youthful physical appearance.

It should be no surprise that hypothyroidism is a leading precursor to hair thinning, and is often a confounding factor in most pattern hair loss sufferers. The fact that thyroid function can be improved with simply the addition of a probiotic is remarkable, and deserves further exploration.

Studies are in the works to see if these thyroid results translate to humans. But if I were to guess — based on all the other directionally equivalent studies on rats and humans for l. reuteri — I’m confident there’s a good chance l. reuteri will help.

Should We Supplement With Lactobacillus Reuteri To Improve Hair Loss?

The jury is still out on whether l. reuteri’s hair promoting effects will translate to humans. But the bottom line is this: studies show that this bacteria is nothing short of a miracle in terms of improving hormonal function, sex appeal, vitamin D levels, and anti-inflammatory T cells (among several other benefits). Should we supplement with this bacteria? Considering no toxicology in humans has been reported — even at 10 billion IU’s per day — I think the resounding answer is, yes.

But that doesn’t mean you should grab the first l. reuteri supplement you find. Here’s why.

Most Studies On L. Reuteri Are On Propietary Strains Of The Bacteria. Cross-Comparing Results Of One Study To Another Is Useless Until We Have Species-To-Species Comparisons

Lactobacillus Reuteri comes in many different strains. And unfortunately, most studies testing l. reuteri’s effects on health are actually testing proprietary strains of L. reuteri — and not the same strain over and over again.

For instance — the studies on l. reuteri increasing serum vitamin D and on l. reuteri improving vitamin B12 deficiencies were done on different strains of l. reuteri. And both of these l. reuteri differed from the strains researched in the l. reuteri – hair health / skin health studies.

The Good News

The studies showing the benefits of l. reuteri on hair health, skin health, thyroid functionality, and t-cell migration were all done on the same bacterial strain. And that bacterial strain is L. reuteri ATCC PTA 6475.

And the better news — this strain of l. reuteri is available as a supplement to humans. And you don’t need a lab order or a doctor to get it.

The Bad News

  1. The l. reuteri studies demonstrating significant improvements to thyroid functionality, skin health, and hair health all fed the mice a dosage of 350,000 IU’s of l. reuteri daily. In humans, if we control for weight, we’d need a dose of several billion IU’s per day to match the same amount that the mice were fed. And unfortunately, most l. reuteri supplements only come in 100 million IU increments. And they’re expensive.
  2. L. Reuteri can colonize our guts within days to weeks, but if we stop supplementing, the bacteria gets outcompeted and dies within days. Unfortunately if we’re not exposed to this bacteria at a young age — it’s very hard to successfully colonize our guts without continued supplementation into adulthood.
  3. The studies demonstrating T cell increases were done in maturing mice and newborns. And while l. reuteri supplementation will certainly help adults with a myriad of health benefits (and potentially hair benefits), it’s likely going to be less effective at improving T cell migration since T cell migration takes place soon after birth — and less so late into adulthood.

Even still, the readers who are experimenting with 100 million IU’s of l. reuteri daily have reported to me improvements in their depression, less anxiety, a more youthful “glow”, and better overall energy levels. In fact, one reader said she’s using l. reuteri to help alleviate autism symptoms in her son — and that while it’s not a miracle cure, it’s helping a lot.

Which L. Reuteri Supplement Should You Use For Hair, Skin, And Thyroid Health?

To reiterate (like I always do): I am not affiliated with any supplements or products outside of this site. And in general, I advise against 99% of supplements as I think they’re a waste of money, energy, and time.

With that said, I’ve done enough research to feel confident in recommending an l. reuteri supplement that checks all of the boxes (the right strain for skin and hair benefits, and the highest number of IU’s that I could find available to humans).

The company is called BioGaia — and they sell a 100 million IU chewable probiotic of l. reuteri in the correct strains — l. reuteri ATC PTA 6475. You can check out their site (and their products) here.

Again, I am not affiliated with this company. And if any readers have found a higher dosage l. reuteri probiotic for humans and of the same strain, please post it in the comments section!

Summary: Lactobacillus Reuteri For Hair Health

Lactobacillus Reuteri is a commensal gut bacteria that’s been shown to improve testosterone levels, increase serum vitamin D, improve vitamin B12 deficiencies, and increase anti-inflammatory T cells. In addition, research in rats shows that l. reuteri may improve skin and hair health by increasing the anti-inflammatory cytokine IL-10 and downregulating the pro-inflammatory cytokine IL-17.

While there’s significantly less research in humans for the benefits of l. reuteri — the good news is that at least so far, studies show the same directional results in humans as they do in rats in mice. As a result, it’s suspected that in humans, l. reuteri supplementation may improve skin health, decrease inflammation, improve thyroid size and functionality, improve symptoms of depression and anxiety, and possibly even increase the percent of our hairs in an anagen (growth) phase — thereby giving the appearance of thicker, shinier hair. (Again, we need more human research to confirm the research on thyroid and hair health).

We’re not yet sure how these results translate to pattern hair loss. If I were to guess, l. reuteri won’t regrow lost hair, but it’ll certainly help prevent the conditions that precede hair loss (certain nutrient deficiencies, hypothyroidism, chronic inflammation, and hormonal imbalances). And for that reason, this bacteria is something we should look into (and even test ourselves) for future research.

L. Reuteri is generally safe for supplementation — with dosages of 10 billion UI’s daily leading to no reported side effects. In fact, of everything I’ve read online and in studies, I haven’t yet found a single negative side effect of supplementing with l. reuteri — only benefits.

If you’re going to try supplementing with l. reuteri, your best bet is the BioGaia product line (I am not affiliated). And if you’re going to test, please keep us posted in the comments section! I love hearing from readers, and the community here appreciates reading your anecdotes as well.

145 thoughts on “L. Reuteri For Hair Loss: A Complete Review”

  1. I’ve been drinking KEFIR twice a week for at least four years. Kefir is a fermented probiotic beverage (looks like cream and smells faintly cheese-like) that is the result of kefir grains interacting with lactose in milk. You make it in your own kitchen and it’s ultra “sustainable.” I’ve been re-using the same grains all this time. Just pour off the kefir-milk, rinse the grains and pour new milk over the grains. Drink the kefir, then wait about three days and repeat the process.

    I enjoy exceptional health and a very high energy level. It’s due in part to regular replenishment of intestinal flora via the kefir.

    There’s a wide variety of kefir types, each containing a unique set of probiotic strains. I just did a quick Google search on “L. Reuteri Kefir” but didn’t see anything (yet).

    I’m not sure which strains are contained is the Kefir I’ve been drinking, but I assume L. Ruterie is either not represented or there’s not enough to save my hair. I’ve been losing hair from the entire top of my head in a disperse pattern (and receding front hairline) for at least as long as I’ve been drinking the kefir.

    It would be GREAT if you (or we as a group) can determine which kefir actually contains L. Reuteri, and how much of it.

    • Hey Tom,

      Thanks for reaching out. Of the research I’ve read, the species l. reuteri isn’t often found in kefir:


      With that said, kefir typically contains several different lactobacillus species — many of which may provide benefit to intestinal health — and possibly even similar benefits to l. reuteri. That research paper reviews the most common bacterial species in kefir — though I’m sure since your own kefir is grown at home, it’ll have a different composition.

      If I find anything else, I’ll let you know!


      • Thanks for your reply, Rob, and for the link.

        I mention Kefir because its probiotic benefits REMAIN in the intestines indefinitely. As opposed to Yogurt where the benefits are expelled daily when…er…you expel solid waste from the bowel.

        If L. Reuteri can be administered via KEFIR that might overcome the apparently high dosage necessary. The RESIDUAL flora might *BUILD UP* to the necessary level and REMAIN in the intestines over time. And drinking Kefir twice a week would continually replenish it.

        If you think it worthwhile, I hope you’ll focus your exceptional research skills on finding a Kefir that contains L. Reuteri or a similarly beneficial strain.

        STONE SOUP
        We all appreciate your efforts and your willingness to share information. I’m hopeful that exchanging information online as we’re doing will lead to “a breakthrough” soon. Keep up the good work.

      • Tom — thank you for the kind words. And I agree with your sentiments — the fastest pathway toward a universal breakthrough will be through sharing research and having people speak up about what’s working for them, and what isn’t. One of the biggest pieces of buried information was that case study on a 78-year old bald man (it’s inside the book) — a photo-montage of a man who accidentally smacked his head on a fire pit, and then inadvertently regrew his entire juvenile hair line over the proceeding six months.

        Imagine if that case study gained more attention from hair loss researchers when it was first published (over twenty years ago). We might’ve already had a universal solution.

        I’ll continue researching and sharing. And in the meantime, thank you for your comments!

        One last thing: I’m not sure bacteria from kefir stay in the gut any longer than bacteria from yogurt. While the strains between the two vary, I think in general, both yogurt and kefir have generally a very hard time permanently colonizing the gut.


  2. Is your research and methods regarding hair loss based on research done on men only? What, if any refers to women and hair loss/thinning?

    • Hey Tiffany — the research cited in this article applies to both men and women. In fact, most of the studies referenced were performed on both males and females. In addition, the methods covered inside the book and throughout my other articles are all geared towards men and women.

      While there’s overlapping etiologies between male and female pattern hair loss, if you’re suffering from diffuse thinning as a woman, I typically suggest testing for the following:

      -SIBO (small intestinal bacterial overgrowth)
      -Iron deficiency
      -Zinc deficiency

      In almost all of the women with whom I work, at least one of those conditions (and in most cases, multiple) are typically part of the etiology for their thinning hair.


    • I’m not sure that the Swansons brand of l. reuteri contains the right species. They don’t specify on the packaging or on the site which strain of l. reuteri you’re buying, so I’d opt for either the BioGaia brand or any other brand that specifies the ATCC PTA 6475 strain.

  3. Hello Rob,

    great info here as always.
    So, if I understand correctly, consuming sourdough bread could help with colonizing L. Reuteri?
    Pardon my ignorance on the matter, is that kind of bread “good” in terms of gluten and inflammation. The word bread has become evil in my mind now…

    Anyway, thanks for your articles,


    • Hey David,

      Thanks for your comment. To answer your question — L. reuteri is very effective at colonizing sourdough — though the bacteria’s actual presence inside store brand sourdoughs is still relatively unknown. It wouldn’t surprise me to find l. reuteri in most sourdough breads, and depending on how the bread was made and which kinds of wheat grains were used — I’m sure there are some sourdoughs that wouldn’t hurt to include in your diet. With that said, I think the better route for getting l. reuteri into your system is supplementation — at least until more research is done on which foods contain ample l. reuteri, and why.


  4. Thanks for the article, Rob.
    I’m considering to experiment with probiotics, anyway, so I might give this a try. Any advice on how much of the lactobactillus reuteri should be taken daily?

    • Thanks Manuel. It’s a tough question to answer! If we’re going to match the rat studies, several billion IU’s daily would be the amount required. However, most l. reuteri supplements with the right strains come in 100 million IU increments. According to the manufacturers, they say that this amount likely elicits the same therapeutic effects — with marginal increasing utility from 100 million IU up through the billions. So, I’d say your best bet is to start with 100 million IU, and then continue from there.


  5. Hi Rob, excellent article one’s again.

    Am I right to assume that Raw cow’s milk has L. Reuteri? Since this is naturally passed from mother to child through breastfeeding so I am assuming it has.

  6. I’ve just ordered the Swanson product with l reuteri. It’s currently half price with buy one get one free and an extra 25 percent off.

    Rob do you not think it’s a good product though? I’m wondering why you picked the biogaia one other lots of options

    • Hey Joe – the issue with the Swanson product is that it doesn’t specify the strain of l. reuteri, and as a result, I can’t in good conscience recommend it — since I could be inadvertently recommending a strain of l. reuteri that possesses little to no health benefits.

      With that said, if you try it and experience any health benefit, please let us know! I’m curious to hear how your experiment goes.

  7. Rob, once again, very interesting writeup. A recent GI test interestingly highlighted that I have no outstanding issues with parasites, yeast, or bad bacteria, but, more importantly had very scant amounts of good bacteria, and not even a mention of commensal bacteria! This aligns fairly well with my low white blood count. Generally speaking it seems my immunity is low, coupled with below average testosterone levels. I can’t help but think there’s a lot of connection there.

    • Chris — thanks for sharing this. And based off what you’ve shared, I agree with your sentiments — that your low white blood count and below average testosterone might be the result of some form of gut dysbiosis — or even missing commensal/beneficial bacteria.

      The good news is that testosterone levels and low white blood cell counts can bounce back fast when the underlying causes are addressed. So it’s all a matter of testing, creating an action plan, executing it, and then reevaluating your symptoms (and going back to the drawing board if necessary).

      I’ve recently undergone a battery of tests for parasite analysis, gluten sensitivity, hormone readings, hormone metabolites, small intestinal bacterial overgrowth, etc. I’ll be sharing the results on the site soon, and an action plan for treatment if anything is off.


      • Rob,
        I’m also going through the same level of thoroughness with my self analysis, let me know if any of my measurements could be useful to your ongoing research. I wouldn’t mind some of my self discovery going to good use.

        I’m health,

      • Chris — thank you! I’d love to take you up on the offer. Email me any time. Maybe we can try an experiment with before-after test results from certain dietary/lifestyle/treatment interventions. That’s what I plan on doing for my tests as well.

    • Chris! My situation is nearly identical. I’d love to connect and share info with you, let me know if you’re interested!

    • Chris! My situation is nearly identical. I’d love to connect and share info with you, let me know if you’re interested!

    • Thanks Vick. Unfortunately the company doesn’t specify the strain of l. reuteri, so I don’t know if it’s the right type. With that said, if you have success trying this, keep us posted!

    • Hey Abdul,

      That sales page mentions that specific strain of l. reuteri (NCIMB 30242) as the strain studied that improves cholesterol synthesis (and thereby potentially serum vitamin D levels). So that strain of l. reuteri should help with at least some of the things discussed in the article! Thought it’s not the same as the strains studied in the mice and rats that improved hair quality and testosterone levels, so we can’t be certain it’ll have any hair effects.


  8. Hey Rob,

    You mention SIBO as a possible cause for hairloss which I think I might have. What would be a good way to treat bacterial overgrowth in the stomach/intestines?


    • Hey Jim,

      It all depends on whether your SIBO is methane dominant, hydrogen dominant, or both. Here’s a great resource for determining which treatments best suit you:


      Otherwise, there’s also a product called Atrantil — which has gained recent attention for its ability to help treat methane-dominant SIBO (the harder-to-treat form of SIBO).

      I’ll be writing more about this in the future. But in the meantime, that site is a good place to start.


    • Hey Joe — I’d be really surprised if CoQ10 alone helped stop your hair shedding. It has some anti-inflammatory effects, but just doesn’t seem enough on its own to really move the needle. In any case, congrats on your progress!

  9. Did you check Danny Roddy’s new Patreon post? it is interesting:

    “What does every Baldness therapy have in common?

    In the The Baldness Field chapter, November 1942, I’m making the case that every major baldness therapy had one thing in common: they increased the anti-inflammatory hormone, progesterone.

    I imagine that castrates are somewhat immune to these degenerative changes affecting hair growth due their higher production of progesterone and deficiency of estrogen, which puts a cap on cortisol, prolactin, and aldosterone.”

    • Hey Michael — I edited most of your quoted material since it wis Danny Roddy’s paid content, and keeping the full quoted text would be unethical to allow on my site. I don’t subscribe to Danny Roddy, but I did read your full comment and found it interesting. Based on what is provided in the text you quoted, it seems more research is required to actually pin down low progesterone as a precursor to pattern hair thinning. But the evidence of an associate between lowered progesterone and androgenic alopecia seems to be there. Whether this is more than associative (as in, whether low progesterone actually causes pattern hair loss) — we don’t yet know. I’ll dig into this more in the coming months.

      • Hi Rob, Michael,
        I only noticed the *edited comment that Rob allowed and while I appreciate Danny’s research, the comment I saw seemed a bit contradictory. Reason is the since most of the steroids are produced in the gonads, wouldn’t castration (physical ) reduce the whole chain of steroids including progesterone ?
        One might say it’s the cellular/tissue progestrone levels that matter but then one can say if the cells steroid status depend on its redox State ( nad+/nadh ratio and nadph/nadp+ ratio) then it becomes tough to know whether castration causes such state at least locally in the scalp. Also, afaik, both T and DHT has a negative effect on cortisol release or a calming effect on HPA axis, wouldn’t castration cause more cortisol signaling because of the lack of protective androgens ?

  10. Hey Rob!

    I purchased your standard package about a week ago and have been doing the massages since. I also started taking mk-7, magnesium, and vitamin d3. I am kind of in the same boat as Peter (Germany), who’s photos is referenced in your book, where I’m thinning a lot in the vertex and I get a little hesitant about applying all 3 of the massage techniques, in my vertex area. With hairline I lose about 20-30 hairs, sides maybe 10, but with vertex I lose around 60. Would regrowth be possible with just pinching? I feel like pressing and stretching where theres still tiny hairs is basically ripping them out since they’re thin and small. I’m not so sure they were going to fall out if I did not do the latter 2 massage techniques.

    • Hey Will — thanks for your support. You can absolutely ease into the massaging. In fact, I recommend it. Especially in the beginning, try capping your massage intensity to limit the amount of hairs shed per session to 15-20. If you shed that hair ten minutes in, that’s okay. End your session, and the next time, taper your intensity to make it the full twenty minutes while still shedding the same (or preferably fewer) hairs.

      In terms of not pressing / stretching — that’s okay too. Just start putting the work in, and in a few months time, your scalp will feel more elastic and you can slowly begin increasing your intensity while shedding fewer and fewer hairs.


  11. Hey Rob,

    I’m taking colloidal silver to protect against pathogens and “bad” bacteria. Would it interfere with supplementation of the l.reuteri (Gaia product)?

    I’m thinking maybe I should separate the time I’m taking them by as much as possible.

    • Hey Aram,

      Colloidal silver is a broad-spectrum antibiotic, which leads me to suggest that it would interfere with several species (including l. reuteri). If you’re going to take both, I think it’s best to spread out your supplementation timings. But if you’re only taking colloidal silver as a preventive to pathogens and aren’t experience any ill-effects of a compromised gut (SIBO, IBS, autoimmunity, skin irritation, chronic fatigue, depression, etc.) — then I’d drop the colloidal silver and focus more on rebuilding the gut rather than killing off any potential pathogenic microorganisms. The reality is that if things are balanced correctly, both the good and the bad can live side-by-side and without issue.


      • Thanks Rob.

        I just wanted to give a quick update on taking the biogaia product for about 1 1/2 months. Within a couple of days I noticed a better sense of relaxation and deeper sleep. I’ve starting waking up more refreshed and find that I can last longer between meals without feeling any crash symptoms.

        I would approximate that my testicle size increased at least 20% and that my sperm count increased by 30%. I’m being moderate with the percentages because I don’t want to exaggerate… but the difference is very noticeable.

        I really love the changes from one simple product. Thanks for continuing to research and update us on these things.

      • Wow! Thanks for the update Aram. And congrats! Sounds like some incredible effects. I’m curious if any other readers have experienced similar benefits. Hopefully a few will chime in.

  12. I ordered some biogaia gastrus. I contacted the company and I only need to take it every other day. So 30 tablets should last two months. I also wondered if it would be possible to ferment food with this strain. It won’t work with vegetables but might work with milk but only in conjunction with other yoghurt strains. Some attempts have been made with probiotic cheese. However they could give no guarantee if the amount of l. Reuteri would increase and there would be no way to measure it.

    • Hey Nick I’ve also brought the same tablets, which are 200 mil per capsule. I plan to take everyday. Why did they suggest every other day out of curiosity??

      • Hi paz! For me they are a bit expensive. So I wondered if cultivation was possible. This seems to be a bit tricky.
        So I wondered if I could take them every other day to reduce the cost. She said if I eat them continously, every other day is fine. If I go on vacation or need antibiotics, she suggested one every day. So there is a difference. I just hope I won’t miss out on the hair benefits by being cheap.

      • She suggested milk at 37C(body temperature) but was worried about other harmful pathogens growing in this setting. So my idea was making yoghurt and adding this gastrus tablet as well. She said the yoghurt culture would protect against pathogens but again could give no guarantee about l. Reuteri increase. I havn’t tried it. I’m making kefir since sunday. I wonder if adding gastrus would just be waste of a tablet. I tolerate the gastrus well. I’m not sure about the kefir yet.

    • Guys, custom probiotic do 2-3 strains of l-reut in powder. It’s not cheap but seems working for me. It’s 100 bln! In 1 gr. I have to agree that from all the supp I ever took ( and it’s ….a lot) there is only few I notice do something for me. Probiotic one of them, not all brands and strains. I feel like most brands do not do anything. Ultimate flora 50 bln it’s first time I felt something good and then I shifted to separate strains which seems to work better

  13. I can also mention that it is safe to take this supplement on long term basis. There are numerous studies. Most of the biogaia products are marketed for kids. As you know the strains can populate and survive in kids since they have not fully developed their microbiom until age of seven. For us it is much harder, I’m not sure it is possible. This of course is good for all the companies selling probiotics. Better than being hooked on cigarettes though. I will report if I feel better from this. I think natto has given me some positive effects. I will also make kefir in a week or two. Gastrus start on Monday.

    • Hey Joe — there are a few sections in the book about the benefits of vitamin K2 and its relationship to calcification. MK-7 happens to be a form of K2 that stays activated much longer than most animal forms of K2. Plus, it’s relatively inexpensive, and I don’t always get enough K2 through diet alone. That’s why I occasionally take it.


    • According to the packaging, that probiotic doesn’t contain the right strain of l. reuteri — at least for our goals. That’s not to say it won’t work, it’s just not a product I can recommend since the effects of l. reuteri might vary depending on the strain.

  14. I’ve discovered a product called Floraphage. Basically, it increases the population of friendly bacteria, so it could potentially be very beneficial for this strain of L.Reuteri. Unfortunately, L.Reuteri wasn’t tested, so I don’t know off the bat whether it will work. I’ve sent an email to the company enquiring about other strains that they didn’t test. I will report back once they reply.
    Regardless of whether it works for L.Reuteri, it may interest some of you, as it increases the population of common, but important, strains such as L. Acidophilus, b.bididum, l.casei etc by 24 fold.
    Unfortunately for me, I’m in the UK and the product is extremely expensive to get shipped over, so I want to know for sure it’s a good product before purchasing. Here is the site:


    • The customer advisor got back to me regarding this product. He said that although non of the L.Reuteri strains were tested, every family of Lactobacillus that were tested showed significant growth when taken with Floraphage. So, this means that it definitely has potential to grow more than the 100million cfu of L.Reuteri atcc pta 6475 that’s provided with each serving of BioGaia.
      I will purchase both products when I’m next paid.

  15. Hey Rob,
    I wanna ask you something totally unrelated to this topic. Have you watched the documentary named: “What The Food”? What’s been told there have a huge impact on me right now. And I’d like to figure out if this documentary is made by some vegan activists or the only aim is to preserve human health? (If you haven’t watched I think you should)

    • Hey Mert — you’re the second person who’s recommended What The Health to me. I’ll check it out this week and get back to you! Thanks again.

      All my best,

    • Definitely worth watching. The doctors appearing in the documentary are definitely not vegan activists by the way. Michael Greger, Neal Barnard, Garth Davis, Michelle McMacken and others are highly renowned physicians with a prestigious educational background.

  16. rob do you think it would be worth creating a closed facebook group so that we could discuss all of your articles and hear feedback from each other etc. i think it would really help

    • hmm a FB group or maybe a forum on this site? Whatever is easier for separating topics as I feel the comments under each article aren’t always directly related to the article, but it’s the only way to communicate.

      • Hey Will,

        Thanks for the suggestion. As the community here has grown, it seems like a forum or FB group would be a natural step forward toward connecting more people and helping expedite information-sharing. My concerns with forums /FB groups are just how much time it takes to moderate them — and how it might create an expectation for me to be even more available for people. I have a hard time keeping up with emails / article comments in addition to researching / writing new articles each week (or at least trying!). But I will absolutely consider this, and maybe try to pilot the idea in the next couple of months.

        Thanks again!

        All my best,

  17. Hey Rob,

    What are your thoughts on applying magnesium oil hair spray to the scalp in addition to ingesting it? I’m curious if it’s safe in attacking decalcification topically and orally. And if it is safe, do you have any recommendation as to how to look for a good one? I see alot of homemade and branded ones, but weary of the labels as I look at all labels with a grain of salt like I do with shampoos now.

    • Hey Will,

      The paradox with magnesium oil is that at a molecular level, it should help with calcium clearance / calcification removal. But in practice, I’ve yet to see anyone using magnesium oil see significant regrowth. This is likely due to calcification being used as an “umbrella term” to describe the blockages observed in balding scalps’ capillary networks. The reality is that these blockages likely also include arterial plaque, cellular debris, and other materials beyond just calcium. The other possibility is that magnesium oil isn’t reaching the targeted areas — even for those dermarolling to increase absorption.

      I don’t think it hurts to use magnesium — either topically, orally, or both. Though if you begin to experience a laxative effect, that’s suggestive that you’re probably having too much and should taper back. I don’t have any recommendations for a good brand, but if you find one you enjoy, please share it here!


    • Hey Michael,

      Thanks for sharing. There’s been some discussion of this theory in the comments of this article:


      There’s reason to believe there’s some sort of causal link between hair loss. Here are the challenges to the theory:

      1) Why is the incidence of subluxation higher in men than women?
      2) Why does the “pattern” of hair loss vary in both men and women?

      Androgens could encourage more bone growth for men and thereby lead to more incidences of subluxation, but the theory is still missing the explanation of the pattern. In any case, there’s no denying that alignment might be connected.

      Another challenge: some men with terrible spinal alignment have been able to maintain relatively solid heads of hair, despite decades of suffering. Steven Hawking is an example: see this photo.


    • Hey Joe — you can certainly try it. I typically like ingesting collagen through bone broths. But others find it easier to take a supplement, and I don’t think it makes much of a difference either way (though the bone broths are typically much cheaper).

  18. Ive noticed something interesting in my 9 months of massages.

    Ive been monitoring my shedding and quality of hair that is shedding.

    Far too many people are worried about shedding, than actually looking at what they are shedding !.

    For the first few months I noticed the shedding hair to be weak, light, and almost in semi growth status that didnt grow that long.

    Hair shed volumes would increase and decrease, but it all contributes to hair growth in my opinion.

    Recently I have noticed that the hair im begining to shed now is thicker, looks more healthier, and slightly longer than before. But still not good enough.

    Im glad sometimes that im shedding these hairs because I can tell that more thicker and better nourished hair is comming , which is precisley what has been happening. This only proves that blood circulation is critical for scalp and hair health.

    My hairline has now moved forward. But slowly…… Still not a hundred percent, but I dont expect it to be until after month 12.

    Im now taking L reuteri to see what it does.

    • Thank you for sharing your experience, Praz.
      How long did it take until you noticed the first improvements in your hairline region?
      I’ve now been doing the massages for 6 months but haven’t seen any hairline improvements yet.

      • Hi Manuel

        In all honesty expect 9 months.

        I experienced regrowth around end of month 8 . With white vellus hair continue to grow. Also it will fill in slowly. You have to be patient.

        Always go by month end rather than beginning. So I class August 20th as end of month 9 .

    • Thanks Michael! Further validation of microneedling as a synergistic tool alongside current hair loss treatments. Very promising stuff!

  19. Rob,

    I think I found a physical, simple and instantaneous way to pump blood into the scalp! All I have to do is just hold my breath and pressurize myself, where my neck, face and temples’ arteries and veins would pop up. I hold it for a half a minute or as long as I can and release! You will unmistakably feel in your scalp the blood rush immediately!

    But somehow, why do I think the problem or the solution is way more than blood supply!–that it is rather what is or is not in the blood which is the problem/solution on hair loss!

    • Hi Abdul.

      I’ve also done this before. However this method can send blood , but will not break down calcification and fibrosis.

      I usu

    • That was a good listen, and would also like robs opinion.

      So using saw palmetto, has benefits as we already know. What’s more interesting is that of liver function process.. could this be why apple cider vinegar might be a good thing to drink.

    • Paz

      I don’t know about you, but I haven’t performed this exercise long enough to see what benefit it would yield! Have you? I should tell you that the first time I did it, I couldn’t believe the calming effect I felt allover my scalp!

      Also, with calcification, couldn’t it be chipped away with Vitamin K if regular blood supply to the scalp is established? why should the scalp calcification be any different than Coronary Artery Calcification ( except possible blood supply difficulties on high-up scalp), which can be cleaned with Vitamin K?