The Vitamin D-Hair Loss Connection
When it comes to the causes of hair loss, most people never suspect a vitamin D deficiency.
Here’s a story about why you should, and why vitamin D can sometimes make the difference between hair loss and hair recovery.
You might’ve seen Jared’s photos on the site. Jared and I started communicating in May of 2014. We exchanged emails to clarify the massage techniques and supporting evidence, then kept in touch for troubleshooting and research-sharing.
Anyway, here are photos of Jared’s hair regrowth over the full year:
His hair recovery is encouraging, but his photos don’t tell the full story. Because around the five-month mark, Jared actually lost most of the hair he’d recovered. The question was: why?
Jared’s Story Of Hair Recovery
Jared started the book’s protocol in the spring and saw signs of thickening relatively quickly. But around winter, his regrowth had stalled. Then came thinning at his hair line, and two months later, his hair was receding again.
This didn’t make sense. In the summer and fall months, Jared saw tremendous regrowth. He hadn’t changed his massage technique. He hadn’t changed his diet. And on top of his hair loss, Jared now also felt depressed.
Jared decided to find out why, so he ordered some blood work – including a 25-hydroxy vitamin D test.
25-hydroxy vitamin D is (debatably) the standard for measuring how much vitamin D is in our body. For anyone who’s done the test, a deficiency is labeled as anything below 30 ng/ml. Depending on your doctor, some even say readings below 40 ng/ml should be marked as a deficiency.
So what were Jared’s 25-hydroxy vitamin D levels? 8 ng/ml. He was severely vitamin D deficient.
Who Cares About Vitamin D?
Vitamin D is critical for hundreds of functions in the body – from wound healing to hormone production to immune functionality. And in winter time, a vitamin D deficiency is extremely common – a clear indicator being depression. There’s even a name for it: Seasonal Affective Disorder.
Jared was definitely symptomatic, and his hair was no longer progressing. Was a vitamin D deficiency contributing? He decided to address the deficiency and find out.
Was Jared’s Recent Hair Loss Caused By Low Vitamin D?
Jared changed his diet to include more foods rich in vitamin D. He also started supplementing with vitamin D3 (and its adjuncts – including, but not limited to, vitamins A and E).
Within a month, Jared felt better. By spring, he was experiencing hair gains beyond his initial progress. And by month eleven, Jared had made a near-complete pattern hair loss recovery.
So what can we glean from this story?
For Some People, Vitamin D Might Be Critical For Hair Regrowth
If Jared hadn’t tested his vitamin D levels, he might not have regrown any hair. He probably would’ve seen the thinning at month five and thought, “Well, I guess this protocol doesn’t work me.”
Instead, Jared analyzed his symptoms, tested his vitamin D, discovered a deficiency, then took action to increase his vitamin D intake. The end-result: a better mood and significant hair recovery.
So just how important is vitamin D? For Jared, vitamin D was the missing link for success. And for many others, the same could be true.
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Vitamin D Deficiency Is A First World Epidemic
This isn’t good. Vitamin D receptors are found in nearly every cell inside our body. Vitamin D is a prerequisite for brain function, hormonal balance, and even the prevention of certain cancers. And in a recent study, over 70% of heart disease patients were found to have low levels of vitamin D.
Given heart disease’s relationship to male pattern baldness, could a vitamin D deficiency also cause pattern hair loss?
The answer is a strong maybe.
The rest of this article uncovers a few (of many) pathways that a vitamin D deficiency can exacerbate hair loss, and what we can do to get our vitamin D levels back on track.
What Is Vitamin D?
Vitamin D is a fat-soluble vitamin. There are a few different kinds, but in its active form, vitamin D isn’t actually considered a vitamin – it’s considered a hormone.
How Do We Get Vitamin D?
We get vitamin D from eating certain animal products (like eggs and fatty fish). But we actually make the majority of our vitamin D when our skin comes into contact with the sun’s UVB rays.
Our skin contains a steroid called 7-dehydrocholesterol. When UVB light connects with this steroid, the photons break apart one of 7-dehydrocholesterol’s chemical bonds, which then converts the steroid into vitamin D3 (an inactive form of vitamin D).
Vitamin D3 then makes its way to the kidneys and liver where it gets converted into the active form of vitamin D – calcitriol. The active vitamin D then gets transported to any cells, tissues, and organs in need – influencing gene expression, immune function, calcium uptake, neural signaling, and everything in between.
All else equal – when our vitamin D levels are adequate, our bodies are well-equipped to keep our health and hormones in check. But if we’re vitamin D deficient, things can start going wrong… Things like decreased immune function, autoimmunity, reduced bone density, and even hair loss.
Low Vitamin D Is Associated With Hair Loss In Both Men And Women
When it comes to vitamin D and hair loss, the research is clear:
- Women 18-45 suffering from sudden onset hair loss tend to have low vitamin D2 levels.
- In men and women, a vitamin D deficiency is closely associated with hypothyroidism – of which a commonly reported symptom is hair loss.
- In premenopausal women, insufficient sun exposure (and likely low vitamin D) is associated with an increased risk of autoimmune thyroid disorder. And the lower your vitamin D, the worse your thyroid condition. In fact, 92% of Hashimotos sufferers – the autoimmune form of hypothyroidism – have low serum vitamin D markers.
But while low vitamin D is associated with both hair loss and hypothyroidism, does a vitamin D deficiency actually cause hair loss?
This is a little harder to answer.
Low Vitamin D Is Related To Hair Loss, But It’s Unclear If It Causes Hair Loss
I’ve yet to find a study showing that a vitamin D deficiency directly causes hair loss (association and causation are two different things).
However, there’s plenty of evidence showing that a vitamin D deficiency contributes to the conditions that precede a balding scalp:
Let’s start with fibrosis – what it is, how it contributes to pattern hair loss, and where vitamin D comes into play.
Fibrosis-Hair Loss-Vitamin D Connection
What Is Fibrosis?
Fibrosis is another term for “excess collagen”. It’s when our bodies over-accumulate connective tissue, and it often occurs during cases of 1) large wounds, or 2) chronic inflammation. The end-result of fibrosis: scarring.
Fibrosis is found all around thinning and miniaturized hair follicles. In the scalp, fibrosis is called perifollicular fibrosis, and to put it simply, it’s when our hair follicles become entrapped in scar tissue.
This scar tissue (fibrosis) then restricts blood flow to the hair follicles, thereby lower its oxygen levels. The follicles then shrink, which causes the hair to thin, until it eventually disappears – leading to pattern baldness. (Note: here’s an article explaining how fibrosis and calcification precede hair loss).
Low Vitamin D Promotes Fibrosis
There are two ways that a vitamin D deficiency promotes fibrosis:
- A vitamin D deficiency increases the expression of the protein toll-like-receptor 4
- A vitamin D deficiency increases the expression of the protein transforming growth factor beta
Mechanism #1: Toll-Like-Receptor 4
The causes of fibrosis are elusive, but researchers may have just recently discovered a mechanism: the activation of toll-like-receptor 4 (TLR4).
TLR4 is a protein that helps activate our innate immune system (our body’s immediate defense to threatening bacteria, pathogens, or toxins). It turns out that TLR4 is higher in areas where there’s fibrosis. Moreover, TLR4 is higher in patients with scleroderma – a condition where the body rapidly accumulates scar tissue for no clear reason.
In a recent study on mice, researchers uncovered that if they modified a gene so that mice could not express TLR4, they could make those mice immune to scleroderma. These TLR4-absent mice developed very little – if any – fibrosis during treatment.
Without Vitamin D3, TLR4 Expression Skyrockets
Vitamin D3 has been found to significantly decrease the expression of TLR4. In some human studies, vitamin D3 decreases TLR4 by nearly five-fold – depending on D3 dosage and time elapsed.
What does all this mean?
Vitamin D3 modulates TLR4 expression. The higher the D3, the less TLR4 expression, the less fibrosis.
The lower the D3, the more TLR4 expression, the more likely fibrosis develops.
Mechanism #2: Transforming Growth Factor Beta (TGF-β)
Transforming growth factor beta (TGF-β) is a signaling protein. Nearly all our cells use TGF-β for one process or another, and in normal amounts, TGF-β is critical for cellular repair.
Vitamin D Receptors Downregulate TGF-β
Interestingly, vitamin D receptors decrease the expression of TGF-β. The more vitamin D receptors present, the lower the TGF-β. And unfortunately this works the other way too. In the absence of vitamin D receptors, TGF-β skyrockets with fibrosis soon following.
Our goal is keep our hair, which means we want to minimize the development of any fibrotic process. Without vitamin D, we’re far less equipped to keep fibrosis at bay.
To make matters worse, vitamin D’s role in hair loss extends far beyond fibrosis – and even to the promotion of calcification.
Calcification-Vitamin D-Hair Loss Connection
What Is Calcification?
Calcification is the build-up of calcium deposits in the body.
Dr. Frederick Hoelzel first published the connection between scalp calcification, restricted blood flow, and baldness over 70 years ago. While studying cadavers, he found that areas of baldness occurred in regions where the scalp was calcified:
“Baldness occurred in persons in whom calcification of the skull bones apparently had not only firmly knitted the cranial sutures but also closed or narrowed various small foramens through which blood vessels pass most prominently in persons with a luxuriant crop of hair.”
Just like fibrosis, calcification precedes hair miniaturization. Arterial calcification acts a blockade to proper blood flow. Since blood carries oxygen, this lowers the oxygen levels of tissues that any “calcified” capillary supports (namely, our hair follicles). Without enough oxygen, our follicles begin to shrink – and eventually disappear entirely.
So where does vitamin D come into play?
Low Vitamin D Is Associated With Increased Vascular Calcification
In some populations, a vitamin D deficiency is associated with increased rates of arterial calcification and even heart disease. Moreover, evidence shows that calcification is higher in those with fewer vitamin D receptors (receptors are activated through vitamin D metabolites – meaning the more vitamin D you have, the more receptors are active).
There’s even evidence of the specific mechanisms by which low vitamin D increases calcification.
Mechanism #1: Low Vitamin D Increases Prostaglandin D2 Expression
You might’ve heard of prostaglandin D2 (PGD2) before. Prostaglandin D2 (PGD2) is a fatty acid derivative, and in 2012, it made headlines when hair loss researchers discovered that…
- Prostaglandin D2 is elevated in the scalps of balding men
- When PGD2 increases too much, human hair stops growing and even recedes
It should be no surprise that PGD2 induces calcification… Meaning that the more PGD2 present, the more likely you are to develop calcification in the affected tissue.
Interestingly, vitamin D3 decreases PGD2 expression – and thereby may prevent calcification (the same calcification that precedes hair loss). And of course, without vitamin D3, the opposite is true. PGD2 increases, and resultantly, so too might calcification.
But PGD2 isn’t the only mechanism by which low vitamin D encourages calcification and (indirectly) hair loss.
Mechanisms #2 And #3: Vitamin D Deficiency May Increase Calcification-Inducing Proteins
In the absence of vitamin D, our arteries begin to over-express proteins associated with inflammation and calcification induction. If over-expressed for too long, these proteins (known as calcification inducers) tend to promote tissue calcification.
Two sets of calcification-inducing proteins that increase in the presence of a vitamin D deficiency are…
The net: if you’re vitamin D deficient, you’re more likely to over-express PGD2 and these proteins, which puts you at a higher risk for arterial calcification… The same calcification implicated in pattern hair loss.
Summarizing The Triggers – How Low Vitamin D Causes Hair Loss
In men and women, infrequent exposure to sunlight and/or low vitamin D is associated with hair loss. Interestingly, low vitamin D is also associated with fibrosis and calcification – two chronic, progressive conditions that may precede hair loss and trigger hair miniaturization.
Low vitamin D might indirectly trigger pattern hair loss by encouraging…
- Fibrosis (by increasing the expression of TLR4 and TGF-β).
- Calcification (by increasing the expression of PGD2, pro-inflammatory cytokines, and MMP).
Now that we know the mechanisms, let’s ask the question that really matters…
Will Increasing Our Vitamin D Status Help Prevent Or Reverse Pattern Hair Loss?
The answer is a strong maybe, and the research is encouraging.
How Adequate Vitamin D Protects Against Pattern Hair Loss
Benefit #1: Vitamin D May Prevent Arterial Calcification
I’ve previously written about the importance of hormonal health, and how testosterone and estrogen are both implicated in not only hair loss, but arterial calcification.
To summarize: evidence shows that testosterone and estrogen (or our testosterone:estrogen ratio) might help mediate the accumulation of calcification.
With heart disease and arterial calcification reaching epidemic proportions, it should be no surprise that men’s testosterone levels today are 22% lower than they were 30 years ago.
If men want to protect themselves from arterial calcification, heart attacks, and even hair loss – there’s plenty of evidence to suggest that increasing testosterone levels (naturally) is protective.
So where does vitamin D come into the equation? Well, it turns out that vitamin D has a huge impact on testosterone.
In Men, Vitamin D Increases Testosterone Levels
Men with healthy vitamin D levels have significantly higher testosterone than men who are vitamin D deficient.
Another study shows that men supplementing with vitamin D3 for one year increased testosterone levels 25% higher against the placebo.
Even more surprisingly, one study revealed that exposing men’s chests to UVB radiation for a few minutes per day for five days straight increased total testosterone by a whopping 120%. And even more interestingly… When the genitals were exposed, total testosterone increased by 200%.
The relationship seems clear: the more UVB radiation (without burning), the more vitamin D, and the higher the testosterone. Given endogenous testosterone’s protective effects against calcification, it should be no surprise that serum vitamin D status is inversely correlated with arterial calcification.
If we want to protect ourselves from arterial calcification (and hair loss), it’s in our best interests to start getting more vitamin D.
Benefit #2: Vitamin D Might Directly Encourage Hair Regrowth
In other words – sunlight and vitamin D might be a prerequisite for new hair follicle proliferation. If we’re not getting enough of either, hair growth might be harder (or impossible) to achieve.
Summarizing The Benefits Of Vitamin D
Vitamin D may be a critical (and overlooked) factor in fighting hair loss. Here’s a summary of its benefits:
- Vitamin D prevents fibrosis by reducing TLR4 and TGF-β
- Vitamin D prevents calcification by reducing the expression of PGD2, pro-inflammatory cytokines, and MMP
- Vitamin D and UVB radiation increases testosterone levels in men
- Vitamin D and UVB radiation increase hair follicle proliferation, and may even be necessary for hair regrowth
Given the above evidence, and given the fact that the majority of Americans are vitamin D deficient, it’s time to start upping our levels. But if we’re going to increase our vitamin D, we need to be smart about it.
How To Increase Our Vitamin D Status (And Support Our Hair)
Recommendation #1: Be Careful About Vitamin D3 Supplementation
Before you start popping D3 supplements at 50,000 IU’s daily, please know there is an upper limit to vitamin D. And if there’s anything we’ve learned in the last two decades of vitamin research, it’s this:
Nutrients and vitamins in their isolated forms don’t always behave the way we expect. Why?
Many of these nutrients and vitamins require other nutrients / vitamins for proper synthesis. Supplementing one nutrient in the absence of its cofactors can lead to problems.
Fifteen years ago, doctors used to recommend supplementing with vitamin D3 alone. Then after a few years, researchers realized that supplementing with vitamin D3 without the proper amounts of vitamin A, vitamin K2, and magnesium actually increased patients’ risk for arterial calcification.
The take away: if you’re going to supplement with any vitamin or nutrient, make sure you’re also including that nutrient’s adjuncts and cofactors.
Too Little And Too Much Vitamin D Can Trigger Arterial Calcification
That’s right. In its supplemented form, too little and too much vitamin D can cause inflammation and arterial calcification. The only difference? The mechanisms.
Here’s a visual showing the relationship between vitamin D dosage, the risk of under- or over-supplementing, and the purported mechanisms of action:
Long-story short: be careful about vitamin D3 supplementation.
Still Want To Supplement With D3?
If you’re going to supplement with vitamin D3…
- Don’t go wild with the dosage. Evidence shows 2,000 – 5,000 IU’s per day is safe for most people.
- If you’re going to go wild, make sure you’re including vitamin D’s proper adjuncts – vitamin A, vitamin K2, and magnesium (among others) – and also through food sources. (Jared did mega-dose on vitamin D, but he was smart about it!)
But there’s an even better (and safer) way to optimize your vitamin D levels: UVB radiation. Or in other words, the sun.
Recommendation #2: Start Getting Into The Sun
If you want to increase your vitamin D safely and naturally, your best bet might be to expose yourself to the sun and as often as possible (without burning).
A few years ago, I decided to reorient my entire schedule toward getting healthy amounts of sun. Even though I live in San Francisco, this wasn’t easy. San Francisco gets some sun throughout the year, but I also work a full-time job outside of this site. I’m inside an office at least forty hours per week, and my commute to work is about ninety minutes total per day. When I leave my apartment each morning, there’s little to no sun. When I arrive home each night, there’s little to no sun.
Why is this a problem? Well, evidence shows that our ability to synthesize vitamin D is directly dependent on the sun’s angle on the Earth. That means that even if it’s a sunny cloudless day, vitamin D synthesis still depends on:
- Latitude. Anyone above 33 degrees North of 30 degrees south (in latitude) might not be able to produce vitamin D during winter months.
- Time of day. 10am to 3pm is when the sun is highest and there’s more potential for UVB radiation.
- Time of year. The sun’s angle shifts with the seasons, and summer time is your best bet for maximum vitamin D synthesis.
A good rule of thumb: if your shadow is as tall or shorter than you, there’s usually enough UVB radiation present for vitamin D synthesis.
When I took into consideration all of this – my location, working hours, and lifestyle – I realized the only way I was going to make any natural vitamin D was if I could get daily sun exposure during working hours.
What did I do? I started packing a lunch. Then I stopped scheduling meetings during my lunch break. Then I started jogging and walking everyday at noon. I found quiet areas to walk with fewer walkers around, and to maximize my sun exposure, I wore shorts and went shirtless. I ended up getting 30-45 minutes of near full body sun exposure daily… Something I still do to this day.
But I didn’t stop there. Each weekend, I made an effort to hike or exercise wherever the sun was shining. Sometimes that meant driving 45 minutes out of the city. Sometimes that meant going to the beach with friends. Whatever the case, it didn’t matter to me – so long as I was getting daily sun exposure between the hours of 10am and 3pm.
A few months in – I felt happier, looked healthier, and even found myself recovering faster from the scalp massages.
But with all that sun exposure, am I now at risk for too much vitamin D, and thereby the same calcification risks we see with those supplementing aggressively on vitamin D?
Can We Get Too Much Vitamin D Through Sun Exposure Alone?
Theoretically, it’s possible. One study on Israeli lifeguards showed that excessive sun exposure (three-five hours per day, most days per week, for years) increased the lifeguard’s serum 25(OH)D3 levels to near mega-supplementation levels, and that these lifeguards have a near 20-fold increased incidence of kidney stones (read: calcification).
But that’s an extreme example – and something no one with an office job could even dream of achieving. On top of that, there’s a good chance that if these Israeli lifeguards supported their high serum 25(OH)D levels with adequate vitamin A, vitamin K2, and magnesium – that incidence of kidney stones would’ve dropped dramatically.
For 99.99% of us, vitamin D toxicity through sun exposure alone is highly unlikely. The reason why? Our bodies have a built-in mechanism that prevents vitamin D toxicity through sun exposure… It’s called a sunburn.
Sunburns: Our Built-In Protection From Vitamin D Toxicity
After a long enough exposure, the sun’s heat on our skin “photo-degrades” the precursors for vitamin D3. This stops our bodies from overproducing vitamin D3 – which is especially important if we’re absent of vitamin D3’s proper adjuncts and cofactors. This is the major difference between supplementation and natural vitamin D3 synthesis. Supplementation is unchecked, whereas our natural D3 synthesis is carefully regulated.
Beyond Vitamin D: Sunlight Also Improves Blood Pressure
The benefits of actual sunlight extend far beyond vitamin D alone. It turns out that sunlight may also stimulate the production of nitric oxide – a known vasodilator – in our blood vessels, which can significantly lower blood pressure and improves blood flow.
Net – if you can do it, sunlight is better than supplementation… which brings up another question. What about sunscreens?
If You Want To Raise Vitamin D Levels With Sunlight, Avoid Sunscreens
For one, sunscreens block UVB light, and UVB light is the spectrum we need to synthesize vitamin D3. The more UVB blocked, the less vitamin D3 created, the less benefit you reap from the sun.
Secondly, sunscreens are full of the same ingredients we’re trying to avoid in shampoo – phthalates, parabens, and other endocrine disruptors. When you put on sunscreen, you’re rubbing these compounds into your largest organ – your skin – and all over your entire body.
Thirdly – and this is a big one – studies show that sunscreen users are actually more likely to burn than non-sunscreen users! Why? It’s simple: sunscreen gives people a false sense of “long-lasting” sun protection… But most sunscreen users never reapply. After an hour or so, sunscreen’s effectiveness wears off, but sunscreen users continue to sit in the sun without reapplying and assume they’re still protected. The end result? They get burned, and often badly. Non-sunscreen users are able to gauge the sun’s intensity more easily – because they can literally feel its heat on their skin (when you apply sunscreen, this sensation slightly dissipates). As a result, they’re more aware of when they’re starting to burn, and thereby more likely to cover up before a burn turns severe.
If you feel like you’re burning, cover up or sit in the shade. When I’m outside and my skin starts to feel too hot, I cover-up with a large hat and sometimes a sarong (light towel). The combo makes me look ridiculous, but who cares?
With that said, please be cognizant about your sun exposure. Know your limits.
Final Vitamin D Takeaways – For Heart Health And Hair Growth
On the one hand, low vitamin D levels are associated hair loss and hypothyroidism. Those with low vitamin D also suffer from increased rates of arterial calcification and fibrosis. Both calcification and fibrosis precede hair loss. It’s likely that low vitamin D contributes to hair thinning through the mechanisms by which it promotes calcification and fibrosis.
On the other hand, high vitamin D levels – achieved through either mega-supplementation or inhuman amounts sun exposure – also promotes calcification and through entirely different mechanisms. This is especially true when vitamin D is supplemented blindly and without its proper adjuncts.
If you have the choice, always opt for sunlight exposure over a vitamin D3 supplement. Get sunlight between the hours of 10am-3pm when our bodies are capable of synthesizing vitamin D3 from the sun. Aim for 15-45 minutes per day, with as much skin exposure as possible, but adjust this depending on your comfort level and your likeliness to burn (don’t overdo it).
If you can’t reorient your schedule, don’t have access to sunlight, or it’s winter time, you can take a D3 supplement… But don’t abuse that supplement, and be sure to also consume with vitamin K2 and magnesium. On top of that, ensure that you’re getting enough vitamin A in your diet through beef and chicken liver.
Lastly – and it bears repeating – I don’t suggest you bake in the sun for six hours each day. With most work schedules, that’s not really possible anyway. However, getting 15-45 minutes of sun exposure daily will help lift your levels significantly – so shoot for whatever is manageable and without overdoing it.
Questions? Please reach out in the comments section!
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Rob English is a researcher, medical editor, and the founder of perfecthairhealth.com. He acts as a peer reviewer for scholarly journals and has published four peer-reviewed papers on androgenic alopecia. He writes regularly about the science behind hair loss (and hair growth). Feel free to browse his long-form articles and publications throughout this site.