If you’ve ever google’d, “The best supplements for hair growth”, you’ll find thousands of articles claiming hair loss is caused by a nutrient deficiency — from iron to iodine to vitamin B-12 — and if we supplement with these nutrients, we can reverse that deficiency, stop our hair loss, and maybe even see hair regrowth.
Sound too good to be true? Well, it probably is.
Truth: our nutritional status influences our degree of systemic inflammation, and thereby our propensity for weight gain, autoimmunity, atherosclerosis, and even disease development…
But does nutrition actually influence our chances of going bald?
The short-answer: it’s complicated. Why? Just look at the end-points.
On the one hand, chronic malnourishment (i.e., too little protein or micronutrients) is closely associated with hair thinning. That’s no surprise. Hair requires energy to grow. Food contains energy (nutrients). If we don’t eat enough food, our bodies reprioritize energy expenditure to essential functions — i.e., whatever is needed to survive. Pumping blood from our hearts is essential; growing hair isn’t. If we lack enough energy for both, we prioritize our hearts and stop growing hair. So at the extreme… nutrition does influence hair loss.
But if that’s true, then how can some nutrient deficient, morbidly obese men have zero hair loss? Why are some pro-athletes — despite working with full-time nutritionists — totally bald?
It’s tempting to say, “It’s because of our genes”, but that’s not entirely true. Yes, our genes influence our predisposition for hair loss. But genes alone can’t explain why the perceived incidence of hair loss is on-the-rise… or why one genetically identical twin can bald faster than his counterpart… or why people moving from the third world to the U.S. are now reporting hair loss — despite no familial history of it.
So… is our first-world diet partly to blame? Or a nutrient deficiency? And if so, what can we do about it?
This article uncovers evidence-based answers.
A Deep Dive Into Diet, Nutrient Deficiencies & Hair Loss
This is part one of a three-part investigative series on nutrition, dieting, and hair loss. The goal: to uncover (and answer) the biggest paradoxes in nutrition-hair loss research.
This is some of the most nuanced content on this site — and for good reason.
The connection between nutrition and hair loss is complex. For example, too little (or too much) of certain nutrients are linked to hair thinning. But contrary to what supplement companies say, fixing a nutrient deficiency is NOT as simple as taking a supplement like iron, biotin, or vitamin D. In many cases, it may make our hair loss worse. In some cases, it increases our chances of morbidity. We’ll uncover why.
First, we’ll reveal nutrient deficiencies and nutrient surpluses connected to hair loss. Then we’ll uncover the difference in nutrient-related hair thinning vs. androgenic alopecia — and why this misunderstanding is leading pattern hair loss sufferers to supplement unnecessarily (and even to our hair’s detriment).
Finally, we’ll answer one of the hardest questions in nutrition-hair loss research: can a nutrient deficiency cause (or even exacerbate) pattern hair loss? The answer isn’t what you’d expect.
[Note: if you have questions or thoughts, please don’t hesitate to reach out in the comments section.]
The Nutrition-Hair Loss Connection
Historians have long noted a relationship between poverty and brittle hair, but it wasn’t until the 20th century when scientists developed the tools to measure those anecdotes — specifically, the impact of wealth on food choice, and the impact of food choice on hair health.
Fast-forward to today: we now have thousands of studies linking vitamin and nutrient deficiencies to dozens of hair loss disorders. And unsurprisingly, most of our discoveries come from studying those who lack nutrition — aka, impoverished populations.
So what have we learned (so far)? For one, diet is 100% connected to hair loss. Diet determines our nutritional status, and our nutritional status determines our ability to grow hair.
Just see this 2010 review on nutrition and hair which reveals that, among other nutrient deficiencies, a…
- Zinc deficiency is linked to diffuse or patchy hair loss — often all over the scalp
- Iron deficiency is associated with diffuse hair loss, and mainly in women
- Selenium deficiency is associated with skin and hair pigment changes, as well as scalp hair loss
- Vitamin A deficiency is linked to phrynoderma — a condition where hair follicles produce too much protein called keratin, which leads to raised skin bumps and (sometimes) hair thinning
- Vitamin B complex deficiencies (B-3, B-6, B-7, B-12) are linked to hair disorders in women
- Essential fatty acid deficiency is linked to hair lightening and diffuse scalp or eyebrow hair loss
And encouragingly, that same review reveals that correcting these nutrient deficiencies can often lead to hair regrowth, and sometimes even full hair recovery.
But don’t get too excited. If we’re going to extrapolate these findings to our own hair loss, context is key.
Because when we look closely at the papers cited in that review, we realize…
- The correlations on nutrient deficiencies and hair loss were made using data on malnourished impoverished populations, and mostly children — i.e., people who lacked access to food (energy).
- In most cases, hair loss from a nutrient deficiency does not resemble pattern hair loss.
These distinctions are important. Why? Because pattern hair loss — also known as androgenic alopecia — accounts for 95% of hair loss cases in men… and it’s not exactly the same as nutrition-related hair loss.
Androgenic Alopecia (Pattern Hair Loss) Is Not The Same As Hair Loss From A Nutrient Deficiency
Here are the key differences.
Pattern hair loss is extremely common — affecting up to 50% of women and 80% of men throughout a lifetime. In men, pattern hair loss often starts as a receding hairline or vertex thinning. In women, it usually starts as even hair thinning across the top of the scalp. Primarily, it’s a hormonally-driven condition. It doesn’t occur in men who can’t produce the hormone DHT, which is why it only develops after puberty and not in children. Finally, toward its mid-to-late stages, pattern hair loss often results in scarring — also known as fibrosis — which is what makes the hair loss a bit harder to reverse (unless you can reverse the scar tissue in balding scalps).
Conversely, hair loss from malnourishment — i.e., a nutrient deficiency — is rare in the first world. It usually presents as increased shedding, brittler hair, diffuse thinning, scalp skin irritability, and hair loss in clumps or patches. It isn’t primarily hormonally-driven — which is why so many nutrition-hair loss studies are done on children, not adults — i.e., before sex hormones kick in. And in general, hair loss from malnourishment doesn’t lead to scarring — which means once we address the nutrient deficiency, we often see hair regrowth.
Finally — for a nutrient deficiency to actually cause nutrient-related hair loss, the deficiency has to be incredibly prolonged, and incredibly severe. That’s why nutrition-hair loss studies use subjects from impoverished populations — because they’ve usually suffered a lifetime of malnourishment.
To summarize: each condition is different in its causes and appearance, so we can’t apply treatments in nutrition-related hair loss to pattern hair loss. It’s like applying treatments in type I diabetes to type II diabetes. While it’s still hair loss (or diabetes), it’s still an apples-to-oranges comparison.
How Nutritional Supplement Companies Exploit These Definitions
Unfortunately, most supplement companies mischaracterize the findings on nutrients and hair growth. They read a study, see the term “hair loss”, and broadly assume its findings apply to 100% of hair loss sufferers.
Unfortunately, this sort of misguidance rarely helps us… and can even make our hair loss worse.
Exhibit A: Supplementing With Biotin For Hair Loss
Biotin, also known as vitamin B-7, is one of the most popular nutritional supplements for women suffering from hair loss. Why? Because studies show that a biotin deficiency is associated with brittle nails and hair… at least, in malnourished children.
So… how does biotin stack up as a hair loss supplement in the first world? Not well.
For instance, this study on biotin supplementation for women complaining of hair loss found that…
“…Treating women complaining of hair loss in an indiscriminate manner with oral biotin supplementation is to be rejected unless biotin deficiency and its significance for the complaint of hair loss in an individual has been demonstrated. …At the same time, potential additional causes of hair loss, for example, androgenetic alopecia, other nutritional deficiencies, and endocrine disorders, must systematically be addressed and treated as needed.”
And of the women with severe biotin deficiencies in that study (38%), biotin supplementation only helped marginally, and usually for hair loss conditions that weren’t characterized as androgenic alopecia. That implies that even for women with a biotin deficiency, a lack of biotin didn’t drive most of their hair loss.
This biotin-hair loss review comes to similar conclusions — and reiterates that we should rule out the more likely causes of female hair loss (like androgenic alopecia) before trying biotin at all.
Unfortunately, when it comes to nutrition and hair loss, biotin supplements are just the tip of the iceberg.
Exhibit B: Nutritional Supplements That Worsen Hair Loss
While low selenium is linked to hair fall, over-supplementation of selenium is associated with hair loss. The same is true for vitamin A — which is why one side effect of Accutane (a synthetic derivative of vitamin A) is thinning hair. Ironically, many hair loss supplements contain both selenium and vitamin A — despite the evidence that deficiencies in the first world are extremely rare.
Moreover, several chronic conditions can occur alongside hair thinning. As a defense mechanism to these chronic conditions, our bodies often will adapt by forcing a nutrient deficiency. In these cases, taking a supplement to correct our “perceived” nutrient deficiency can literally kill us. And unfortunately, many hair loss supplements contain these nutrients. [More on this later.]
Knowing this, it’s no surprise that a 2017 review on nutrient supplementation for hair loss concluded that…
“…some supplements carry the risk of worsening hair loss or the risk of toxicity.”
The bottom line: if we don’t know why we’re losing our hair, and we don’t test for a nutrient deficiency, we might be doing more harm than good.
Is Pattern Hair Loss Connected To A Nutrient Deficiency?
In the U.S., hair loss exclusively due to a nutrient deficiency is rare. At the same time, pattern hair loss is a common condition, and in forums and natural health blogs, it’s widely assumed that most Americans have a nutrient deficiency.
But is that actually true? And if most Americans do have a nutrient deficiency… is it associative or causative to pattern hair loss?
These are big questions, and to get answers, we need to do some digging. First we need to find out how common pattern hair loss is, how common nutrient deficiencies are, and our likelihood of having both.
Then we need to uncover if people with pattern hair loss suffer disproportionately from a nutrient deficiency… and if so, if the relationship is mere coincidence or something more.
I know it may seem unnecessary to go so far backward to answer this question, but please bear with me. It’s important to question widespread scientific dogma (for example, the idea that we should “ice” our injuries)… because oftentimes, the dogma turns out to be wrong.
Pattern Hair Loss: Prevalence In The U.S.? High.
In the U.S., pattern hair loss (androgenic alopecia) is estimated to affect 80 million of 250 million adults nationwide. That’s 32% of adult men and women — which is lower than I expected.
But if we dive deeper into the data, that percent is probably understated.
For instance, androgenic alopecia incidence tends increase ten percentage points for every decade of life — so 20% of males suffer from hair loss at 20 years old, 30% by 30, etc. And some researchers believe the percent of caucasian men who will suffer from androgenic alopecia, if they live long enough, is 100% (America is ~75% caucasian). Even for non-caucasians, this first-world survey (on Singaporeans) found that by 80 years old, 100% of Singapore men were balding. And a few hair loss researchers have gone on the record to say that by the time hair loss is noticeable, we’ve already lost 30-50% of our hair.
Taking this into account, it’s more likely 50%+ of U.S. adults have some degree of pattern hair loss, and that almost all American men will experience some pattern hair loss if they live long enough.
And what about a nutrient deficiency? Are these as common in the first world as pattern hair loss?
The truth: it’s unclear.
Nutrient Deficiency: Prevalence In The U.S.? It’s Debated!
Defining a nutrient deficiency is hard — because it’s entirely dependent on where we set “healthy” nutrient thresholds (where we draw a line between “normal” and deficient)… and what we actually measure (circulating nutrients in the blood, or tissue nutrients — like balding scalp skin tissues).
The best data we have on population-level nutrient status comes from the Center For Disease Control (CDC). But the CDC’s reports are far from perfect, and resultantly, are up for interpretation.
For instance, while a 2012 report from the CDC found that less than 10% of Americans have a nutrient deficiency, that same report…
- …doesn’t measure all vitamins and nutrients, and…
- …uses American reference ranges to determine nutritional status, rather than functional medicine ranges (which are much stricter) or other country’s ranges. For example, Japan’s threshold for a vitamin B-12 deficiency is in the middle of “normal” in U.S. reference charts. If the CDC had used Japanese ranges to test for vitamin B-12, the majority of Americans would be vitamin B-12 deficient.
And if we look at our nutrient status as a function of what we eat (our diets), things look way worse.
Data summarized by the U.S. Department Of Agriculture shows that 56% of Americans aren’t eating enough magnesium, and 93% aren’t eating enough vitamin E to meet basic metabolic requirements.
Even worse, this analysis on the diets of seventy American athletes found that 100% aren’t eating enough nutrients to meet their recommended daily allowances (RDA) — especially in terms of zinc, iodine, vitamin D, vitamin E, and overall calorie intake. That’s right. Not a single athlete was meeting their RDA.
The “RDA” is the minimum amount of a nutrient required for general “good health”. In other words, it’s the minimum standard to ensure we’re getting enough nutrients to function — rather than the amount needed for a true therapeutic dose.
Why Aren’t We Meeting Our RDA’s Anymore?
Unfortunately, our dietary choices aren’t entirely to blame for missing our RDA’s. In the past 100 years, we’ve seen a drastic decline in the nutritional profiles of fruits and vegetables — a phenomenon known as soil nutrient depletion.
Nutrient depletion is the mainly due to poor practices in farmland management (i.e., no crop rotation, forced higher crop yields, etc.). Its effects on food quality is drastic. Just see this table from Mineral Depletion of Foods 1940-2002 — which summarizes the 60+ years of data on the declining nutritional quality of fruits and vegetables (among other things):
Weighing The Evidence: Is The First World Actually Nutrient Deficient?
Again, that 2012 CDC report suggests that less than 10% of Americans are nutrient deficient. But that same report 1) uses conventional reference ranges to determine Americans’ nutrient statuses, and 2) only measures a select group of vitamins and nutrients.
At the same time, food quality and dietary analyses suggest that 93% of Americans don’t eat enough vitamin E, 100% of American athletes are meeting at least one RDA, and nutrient soil depletion trends in the first world are making fruits and vegetables half as nutritious as they were sixty years ago.
This suggests one of two things…
- The CDC report is wrong, and most Americans are actually nutrient deficient, or…
- The CDC report is right, and Americans are meeting their nutritional needs outside of their diets
That second point isn’t out of the realm of possibilities. About 70% of Americans take some sort of nutritional supplement, which may offset the difference between dietary nutrient ingestion and actual nutritional status. Our gut microbiome may also help. Gut bacteria can produce, synthesize, and assimilate micronutrients like vitamin B-12 and vitamin K, and may offset some nutrient deficiencies in our diets.
But nutritional supplements and gut flora probably can’t explain the entire gap between the CDC’s findings (i.e., less than 10% of Americans have a nutrient deficiency) and the reality of our diets (i.e., nearly 100% of us don’t meet our RDA’s). My guess? It’s likely the CDC report severely understates just how nutrient-deficient we are. It doesn’t measure all the right variables, or the right reference ranges.
The bottom line: we’re all probably nutrient deficient. Most Americans are likely sub-clinically or clinically deficient in at least one nutrient — regardless of whether they’re losing hair.
But Does A Nutrient Deficiency Cause Androgenic Alopecia?
We’ve now established that a nutrient deficiency and pattern hair loss are, at a minimum, associative. One possible explanation: it’s simply because both conditions are so common.
These types of associations happen all the time, and they don’t imply causation. For instance, ice cream sales are associated with shark attacks. Ice cream sales increase on warm sunny days, and on warm sunny days, people go to the beach and swim. But ice cream sales don’t cause shark attacks.
Is the same true for a nutrient deficiency androgenic alopecia? Is this a case of association, not causation?
To find out, we need to uncover if people with androgenic alopecia suffer disproportionately from nutrient deficiencies. So let’s look at the research.
Do People With Pattern Hair Loss Have More Nutrient Deficiencies?
This Indian study found that more than 90% of androgenic alopecia subjects were deficient in histidine (an essential amino acid) and alanine (a non-essential amino acid). Moreover, in men with pattern hair loss, more than 10% had a zinc deficiency… and almost 30% had a copper deficiency.
Unfortunately, that study didn’t include age-matched, non-balding controls — which means we can’t say if those deficiencies are more pronounced than in Indians who aren’t balding. And while studies in India suggest these nutrient deficiencies are more extreme than the general population, we can’t make an apples-to-oranges comparison and feel good about it.
But maybe we don’t have to. Because here’s where things get interesting.
This Turkish study showed men with androgenic alopecia do have low zinc and copper levels… and that those levels are statistically significantly worse than non-balding counterparts.
That’s a big revelation. It implies people with pattern hair loss may sufferer disproportionately more from nutrient deficiencies. The question is… Why?
And this is where things get very complicated.
Can A Nutrient Deficiency Exacerbate Pattern Hair Loss?
Telogen effluvium from a nutrient deficiency creates more opportunities for hair follicle miniaturization
Hair loss from a nutrient deficiency is the result of disruptions to our hair cycle – often due to telogen effluvium (i.e., excessive hair shedding). This type of hair loss is temporary; if we correct the nutrient deficiency, we can normalize our hair cycle and any lost hair will typically return within 3-8 months.
Androgenic alopecia can involve excessive hair shedding, but its defining characteristic is hair follicle miniaturization. In other words, the diameter of each hair gets smaller over a series of hair cycles. Interestingly, miniaturization only occurs between hair cycles (i.e., after a hair sheds and when a new follicle begins to form to replace it). That means that anything that triggers excessive hair shedding triggers more opportunities for hair follicle miniaturization.
Resultantly, nutrient deficiencies that lead to telogen effluvium can cause excessive hair shedding that accelerates miniaturization in androgenic alopecia. This is known as telogen effluvium unmasking androgenic alopecia.
So, there certainly is potential for cause-and-effect here.
Mild nutrient deficiencies tend to associate with conditions that are commonly present alongside androgenic alopecia
There are varying severities of nutrient deficiencies. For instance, you can be barely deficient… or severely deficient. And interestingly, our symptoms of a deficiency change based on its severity — from no symptoms at all to a full-blown bodily shutdown.
So let’s look at the end-points of nutrient deficiencies (severely deficient versus barely deficient), and compare which conditions are associated with each category.
At the severe end of the spectrum (extreme deficiency), we see conditions like scurvy (the near-full absence of vitamin C), rickets (the near-full absence of vitamin D), or nutrient-related hair loss (the near-full absence of zinc, selenium, protein, and many other nutrients). [Again, American diets are far from perfect, but they often provides enough nutrients to avoid extreme deficiencies. So in the U.S., hair loss exclusively from a nutrient deficiency is rare].
At the less severe end of the spectrum (just barely deficient), we see conditions like hypothyroidism, hyperparathyroidism, small intestinal bacterial overgrowth, and polycystic ovarian syndrome.
So let’s graph this out. The green text represents conditions associated with less pronounced nutrient deficiencies; the red text represents conditions from extreme nutrient deficiencies.
Now… what is so surprising about the above chart?
Those conditions in green are all associated with pattern hair loss… and the conditions in green occur alongside just mild nutrient deficiencies.
That’s right. Mild nutrient deficiencies are correlated with the chronic conditions most commonly linked to androgenic alopecia. And when we dive deeper, we begin to understand how just the slightest nutrient deficiency might exacerbate pattern hair loss.
The Link Between Nutrients, Chronic Conditions, & Androgenic Alopecia
First, here’s how each of these conditions associated back to androgenic alopecia.
One of the first signs of polycystic ovarian syndrome (PCOS) is female pattern hair loss. Interestingly, PCOS is associated with slight (but significant) deficiencies in vitamin B-12, C, D, and calcium.
One of the first signs of hypothyroidism is hair thinning (often diffuse and similar in pattern to androgenic alopecia). Hypothyroidism is also linked to an iodine and selenium deficiency.
A small intestinal bacterial overgrowth (SIBO) leads to deficiencies in many trace elements and B-vitamins. It’s also a condition present in nearly every female pattern hair loss sufferer with whom I’ve worked.
Hyperparathyroidism is linked to both low vitamin D levels and diffuse thinning across the entire scalp — and is nearly identical to the pattern in female pattern hair loss.
Which Came First: The Nutrient Deficiency, The Condition, Or The Hair Loss?
It’s hard to say. At this point, separating cause and effect depends on the person and the condition.
Here are just two examples to highlight how complicated things get.
PCOS is associated with a wide range of nutrient deficiencies. Oftentimes, symptoms (like hair loss) improve by correcting those nutrient deficiencies. So it’s possible that for some women, PCOS symptoms are partially rooted in a nutrient deficiency (i.e., deficiency first, condition second).
But in some cases (and likely, the majority of cases), PCOS-associated nutrient deficiencies are actually due to a compounding condition: a small intestinal bacterial overgrowth (SIBO). In this scenario, PCOS is secondary to SIBO — as are the nutrient deficiencies (i.e., condition first, deficiency second).
Hyperparathyroidism can occur when a tumor forms on a parathyroid gland — interfering with our ability to produce parathyroid hormone. When our bodies can’t regulate parathyroid hormone, we also have trouble regulating blood calcium levels — and serum calcium increases.
As an adaptive response, our bodies will lower vitamin D levels — since too much vitamin D in the presence of high calcium can lead to arterial calcification. In this case — it’s tumor first, condition second, and an adaptive nutrient deficiency third.
Can Nutritional Supplements Improve These Conditions (And Our Hair)?
We should never assume yes. And when we go down the list, we realize that in many cases, a nutritional supplement will either be useless, or dangerous.
If your PCOS is, in part, due to not eating enough of the right nutrients — then nutritional supplements can often improve your symptoms (and in some instances, stop hair loss).
But if your PCOS is compounded with a SIBO infection (as is often the case), it’s likely that your nutrient deficiency isn’t only due to not eating enough. Rather, the deficiency is due to bacteria (or yeast) getting to the nutrients you ingest before your small intestine can assimilate them. In this case, a nutritional supplement might actually just encourage the overgrowth of more bacteria. Instead, you should first opt for a SIBO treatment, then address the nutrient deficiency after you’re clear.
The causes of hypothyroidism are multi-faceted and not typically due to nutrition alone. Having said that, hypothyroidism is most often associated with an iodine deficiency. Knowing this, many people choose to supplement with iodine — in hopes of improving their symptoms. Sometimes, this helps.
But ironically, whether iodine will help actually depends on your type of hypothyroidism. If you have the most common form of hypothyroidism in women — hashimotos thyroiditis — supplemental iodine may actually make your condition worse. And this study found that ironically, iodine restriction reversed hashimotos in 78% of subjects.
The bottom line: if you have hypothyroidism, you probably also have an iodine deficiency. But if you supplement with iodine, you might actually worsen your condition.
Many women with hair loss also have an iron deficiency. And oftentimes, if these women get more iron into the body (either through dieting or supplements), they see improvements in their hair loss.
Having said that, anemia isn’t always due to low iron. There’s actually a case where our bodies will force low iron stores as a defense mechanism. This is especially true in low-grade, asymptomatic blood infections.
Here’s a gist of what happens:
Pathogenic bacteria feed off iron to survive. And if a pathogen enters our blood stream, our bodies will respond by lowering iron stores in an attempt to reduce the proliferation of that bacteria. This is a condition known as anemia of inflammation — and health professionals who don’t run both iron and ferritin panels on their “anemic” patients miss it all the time. The end-result: the recommendation to supplement with iron, the proliferation of the pathogen, and oftentimes the death of the patient.
Once again — the takeaway is that if you’re presenting with hair loss and an iron deficiency, you absolutely have to run the right diagnostic tests before supplementing. [Note: an article about iron and hair loss is coming soon.]
Final Thoughts: The Nutrition-Hair Loss Connection
The connection between nutrients and pattern hair loss is incredibly complicated, and it’s unclear just how far we can implicate poor nutrition with androgenic alopecia. Even still, here’s what we know:
Nutrient-related hair loss occurs under extreme nutrient deficiencies. This is uncommon in the first world, and it’s different than pattern hair loss (which accounts for 90%+ hair loss cases in the first world).
Despite this, supplement companies continuously misinterpret hair loss studies on malnourished populations — implying that if biotin can regrow hair on a starving child suffering from a lifelong biotin deficiency, then supplementing with biotin must help hair loss for people who can actually afford to supplement (i.e., the first world). This couldn’t be further from the truth.
It’s difficult to separate association versus causation when it comes to nutrient deficiencies and pattern hair loss — because both are so widespread. Having said that, evidence suggests people with androgenic alopecia may suffer disproportionately from nutrient deficiencies — particularly in terms of amino acids, zinc, and copper.
It’s also true that nutrient deficiencies — when severe enough — can trigger hair shedding bouts that accelerate miniaturization in androgenic alopecia. So if we’re fighting pattern hair loss, it’s critical to make sure our nutrient levels are in-check so that we’re not shedding excessive amounts of hair due to telogen effluvium.
Interestingly, less severe nutrient deficiencies are linked to other conditions associated with pattern hair loss: PCOS, hypothyroidism, hyperparathyroidism, a SIBO infection, and even anemia. In some cases, nutritional supplementation may help improve the condition and marginally improve hair loss outcomes.
But I can’t stress this enough: this is a case-by-case basis. Hair loss sufferers who want to take a nutritional supplement should first test for a nutrient deficiency, and then the chronic conditions associated with whatever deficiencies they present — and before they supplement. Failure to do so may make waste money, waste time, worsen hair loss outcomes, and even increase morbidity.
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 five 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.