Vitamins for hair loss: what's worth supplementing, and what won't help?
Iron, vitamin D, zinc, biotin, hair vitamin complexes. I go through which ones have a real deficiency-correction logic, where the evidence contradicts itself, and when vitamin deficiency isn't the cause of the shedding.
Why hair vitamins didn't help me
My hair started falling out when I was 16. For years I spent money on hair vitamins, hair tonics and "anti hair loss" shampoo, because I had no idea it had a hormonal background. None of it helped.
What I didn't know back then: it all comes down to one question. Is something missing from your body, or is your hair thinning according to its own genetic program. The answer is different for each, and the label "hair vitamin" blurs exactly that distinction.
For each nutrient below I look at the same three things: what was measured, on whom it was measured, and what the authors themselves say about the limitations.
Correcting a deficiency versus "hair vitamin as treatment"
The matrix cells of the hair follicle divide very quickly and turn over rapidly. That's why they react sensitively to low calorie, protein, fatty acid, vitamin or mineral intake: the follicle exits the growth phase early, and shedding starts a few months later. Almohanna 2019
If a nutrient is actually deficient, replacing it can also affect the hair, because you're correcting the deficiency. If you have no deficiency, taking more of the same nutrient doesn't produce more hair. In that case the follicle is slowing down for a different reason, and intake has no effect on that.
On the shelf these two situations get mixed into a single box.
Iron and ferritin
This is the nutrient most often linked to hair loss, and it also has the most studies behind it. Iron store status is estimated with serum ferritin. Ferritin, however, rises in inflammation, infection, cancer and liver disease, so an apparently normal value can still hide empty stores. Almohanna 2019
The second problem is that there's no consensus on where deficiency begins. Studies choose a cutoff somewhere between a ferritin of 15 and 70 µg/L, meaning the same person can count as deficient under one definition and not under another. Almohanna 2019
A controlled study of 381 women found that iron deficiency was common among women, but was not more common in female pattern hair loss or chronic telogen effluvium than in a control group without hair loss. Olsen 2010 A review reaches the same conclusion: currently there isn't enough evidence to recommend iron deficiency screening for every hair loss patient. Trost 2006 Data on the effect of iron replacement in telogen effluvium are likewise limited, although some controlled studies did see improvement. Almohanna 2019
What's actionable here: iron is worth measuring if there's another sign pointing to it. Heavy periods, pregnancy, fatigue, paleness, a meat-free diet, a known digestive condition. That means a blood draw, a complete blood count and ferritin. If you do have a real deficiency, it's worth correcting for the hair and for everything else too. The replacement dose should be set by a doctor, because iron can be overdosed.
Vitamin D
The vitamin D receptor is also present in the hair follicle. A rare inherited condition shows this most clearly: a mutation in the receptor's gene causes vitamin D resistant rickets, and it comes with sparse body hair, often complete hair loss. Almohanna 2019 So the hair follicle does have business with vitamin D.
From here, though, the picture splits by the type of shedding. In alopecia areata, a patchy autoimmune form of hair loss, a pooled analysis of 14 studies covering 1,255 patients and 784 controls found significantly lower vitamin D levels. Almohanna 2019 In female pattern hair loss and telogen effluvium the data contradict each other: some studies show lower levels, and some find no association at all. Almohanna 2019
A vitamin D test is a cheap lab test, and if it's low, replacing it is worthwhile regardless of hair. There's no data, though, that vitamin D would bring back pattern thinned hair.
Zinc
Hair loss is one of the known signs of confirmed zinc deficiency, and hair can regrow with replacement. Almohanna 2019 This applies to a genuinely demonstrated deficiency, which is rare: it's typically caused by malabsorption, inflammatory bowel disease, alcoholism, anorexia or a very one-sided diet. Almohanna 2019
For everyday hair loss the data aren't consistent. In a measurement of 312 hair loss patients, average serum zinc was lower than in the control group, but the average still stayed within the 70-130 µg/dl reference range. The proportion of values below 70 µg/dl was only higher in the alopecia areata and telogen effluvium groups. Kil 2013 The review literature therefore doesn't recommend routine zinc screening in hair loss. Almohanna 2019
Two studies say opposite things about replacement, both in alopecia areata. In a 1981 double blind, placebo controlled study, 220 mg of zinc gluconate twice a day for three months brought no change. Almohanna 2019 In another, an open study with no control group, 15 patients with low zinc levels received 50 mg of zinc gluconate daily for 12 weeks, and 9 of them showed a favorable response, which the authors themselves didn't find statistically significant. Park 2009
If you take a high dose of zinc long term, one thing is worth knowing: zinc and copper are absorbed through the same intestinal transporter, so they compete with each other. Kil 2013 The exact dosage is set by the product label.
Biotin
Biotin is the most common ingredient in hair vitamins.
Biotin deficiency does cause hair loss. Severe biotin deficiency, though, has never been reported in a healthy person eating a normal diet, and biotin intake in a Western diet is sufficient. Almohanna 2019 Deficiency is typically tied to a specific cause: an inherited enzyme deficiency, malabsorption, long term antibiotic treatment, taking valproate or isotretinoin, eating large amounts of raw egg. Almohanna 2019
A systematic review found 18 published cases where hair or nail condition improved after taking biotin. All 18 patients had an underlying condition causing the poor hair or nail growth. Patel 2017 Little research supports using biotin in healthy people. Patel 2017
The review literature's conclusion: biotin deficiency causes hair loss, but there's no evidence based data that biotin supplementation produces hair growth. Almohanna 2019
Biotin can throw off your lab results
A large share of lab tests rely on biotin-streptavidin binding. If a sample contains more biotin than usual, the test can give a falsely high or falsely low result, depending on how the test is built, and the wrong result can lead to the wrong patient care or the wrong diagnosis. FDA guidance
What this can affect: thyroid hormones (TSH, FT3, FT4), parathyroid hormone, estradiol, testosterone, progesterone, DHEA-sulfate, vitamin B12, PSA, LH, FSH, as well as cardiac markers and tumor markers. Almohanna 2019
The most severe documented case involves troponin, the lab marker for a heart attack. According to the FDA, biotin from a supplement caused a falsely low troponin result, which meant the heart attack diagnosis was missed, and the patient died. Almohanna 2019 The FDA continues to receive reports of falsely low troponin results. FDA
The adequate daily biotin intake set for adults is 30 micrograms, and hair-skin-nail supplements contain many times that amount. Almohanna 2019 If you take biotin and go for a lab test, mention it. This matters most with thyroid complaints and chest pain.
Combined "hair vitamin" products
Most products on the shelf aren't a single nutrient. Biotin, zinc, selenium, iron, B vitamins, amino acids, collagen and plant extracts in one capsule.
These have been studied too. A 2023 JAMA Dermatology systematic review specifically looked at their effect on people with no known nutrient deficiency: it processed 30 publications, including 17 randomized trials. The studies with the highest quality evidence showed possible benefit for several products and nutrients, including branded complexes (Viviscal, Nourkrin, Nutrafol, Lamdapil, Pantogar), zinc, tocotrienol and pumpkin seed oil. Side effects were rare and mild for every agent. Drake 2023
The authors' conclusion reads: the results should be interpreted in light of each study's design, yet the work suggests that supplements may have a role in treating hair loss, and larger randomized trials with active comparator arms are needed going forward. Drake 2023
If hair improves alongside a ten-ingredient capsule, that doesn't reveal which ingredient did it, nor whether an existing deficiency was simply being corrected in the process. And if a study compares the product to placebo, that says nothing about where it stands relative to treatments backed by more data.
What the label on the box actually means
Only approved claims may appear on supplement packaging, and the list is contained in Regulation (EU) 432/2012. There are four entries in total for hair: 432/2012/EU
- "Biotin contributes to the maintenance of normal hair."
- "Zinc contributes to the maintenance of normal hair."
- "Selenium contributes to the maintenance of normal hair."
- "Copper contributes to normal hair pigmentation."
These claims describe the nutrient's normal physiological role, and may only be used if the product reaches at least a "source" level of that nutrient. 432/2012/EU The word "hair loss" doesn't appear in the regulation even once. So the sentence on the box describes the nutrient's physiological role, nothing more.
What can make you shed more hair
More isn't always better, and for two nutrients it works the other way around entirely.
Excessive intake and excessive supplementation of vitamin A can cause hair loss. The tolerable upper intake level set for adults is 10,000 IU of preformed vitamin A per day. The mechanism is that the liver's vitamin A storage and transport system has a finite capacity, and once the level gets too high, vitamin A spills over into circulation. Almohanna 2019
For selenium, intake above 400 micrograms a day can cause toxicity, and hair loss is one of the symptoms of selenium toxicity. Almohanna 2019
Rapid weight loss belongs here too. In one reported case series, nine patients developed telogen effluvium two to five months after starting an aggressive diet, alongside a weight loss of 11.7-24 kg. Almohanna 2019
When vitamin deficiency is the cause of shedding, and when it isn't
Two different things look like hair loss, and the nutrient question is relevant to only one of them.
Telogen effluvium. Hair thins evenly across the whole scalp, and noticeably more strands come out when washing or combing. Shedding typically starts two to three months after the trigger, because that's how long it takes for the resting phase to end. Possible triggers include childbirth, high fever, surgery, blood loss, chronic illness, an overactive or underactive thyroid, a medication change, severe protein, fatty acid or zinc deficiency, starvation and sustained calorie restriction. Asghar 2020 The acute form lasts less than six months, and resolves on its own in 95% of cases. Asghar 2020 This is where a workup makes sense: if the trigger is identified and resolves, the hair can grow back.
Pattern (androgenetic) hair loss. In men it starts at the temples and the crown, in women the part widens, and the strands get thinner cycle after cycle. The mechanism is hormonal: DHT, produced from testosterone, shortens the growth phase in genetically sensitive follicles. I wrote about this separately: what DHT is, and what it does to the follicle. A vitamin doesn't change this mechanism.
The two can also occur at the same time, and that's the most common source of confusion. A nutrient deficiency stacks on top of hormonally thinning hair, shedding spikes, and replacement brings it back down to the earlier level. In that case the vitamin resolved the added shedding, while the thinning itself continues.
If you don't know which one is yours, this can help: the pattern selector, as well as the male pattern hair loss and female hair loss pages.
Where microneedling fits into this
Microneedling doesn't affect hormones or nutrient levels either. The needle opens temporary microchannels in the upper layer of the scalp, and the puncture triggers a local wound healing response from the body around the follicle.
In hair loss this was studied with a dermaroller, alongside minoxidil: the microneedling group showed a greater change in hair count than the group using minoxidil alone. Dhurat 2013 Both groups received minoxidil, so the difference is what microneedling adds on top of minoxidil. The device there was a 1.5 mm dermaroller, not the 1 mm stamp used at home. Dhurat 2013
For pattern hair loss, I wrote separately about the agents with the most data behind them: minoxidil, finasteride and dutasteride, as well as natural DHT blockers. And on at-home microneedling: the 1 mm stamp on the scalp.
Frequently asked questions
Which vitamin deficiency causes hair loss?
The documented nutrient deficiencies that can go along with hair loss: iron, zinc, biotin, vitamin D, plus severe protein and fatty acid deficiency, and general calorie restriction. Almohanna 2019 Asghar 2020 In practice, iron and vitamin D are the ones worth measuring, because they're the most common, and both can be determined with a simple blood draw.
What should I take for hair loss if I don't know what's causing it?
The order works the other way around: measure first, then replace. Complete blood count, ferritin, vitamin D, thyroid (TSH). If any of these are off, correcting it should happen, and the hair may respond to that. If everything is normal, the cause of the shedding lies elsewhere, and no change should be expected from nutrient replacement.
Which is the best vitamin for hair loss?
Asked this way, there's no good answer. The nutrient that helps is whichever one you're deficient in. The 2023 JAMA Dermatology review, looking at people with no deficiency, found possible benefit for several products and nutrients, and the authors say supplements may have a role in treating hair loss. They also add that the results should be viewed in light of the studies' design, and larger trials with active comparator arms are needed. Drake 2023 A responsible ranking can't be built from this.
Is drugstore hair vitamin different from a pharmacy one?
Both are food supplements, the same legal category, and the same approved claims apply to them. 432/2012/EU The difference is in the composition and the dose. If you're replacing a specific nutrient, check the amount on the label and compare that.
How much biotin does hair need?
The adequate daily biotin intake set for adults is 30 micrograms, and an average diet covers that. Almohanna 2019 Hair-skin-nail supplements contain many times that amount, and there's no evidence based data that the surplus produces hair growth without a deficiency. Almohanna 2019
What side effects does biotin have?
Toxicity from biotin itself hasn't been reported. Almohanna 2019 The practical risk is with lab tests: a high dose of biotin can produce falsely high or falsely low results in thyroid, sex hormone, PSA, cardiac and tumor marker tests. FDA guidance If you're going for a lab test, mention that you take biotin, and ask how long before it you should stop.
Does hair grow back after hair loss caused by iron deficiency?
If iron deficiency really did trigger the shedding, correcting the deficiency can restore the hair cycle, and the strands can grow back, because the follicle wasn't destroyed. The process is slow, measured in months. One note of caution: there isn't enough evidence for the effectiveness of iron replacement in telogen effluvium, although some controlled studies did see improvement. Almohanna 2019 If your iron is fine and the shedding still continues, another cause needs to be found.
How long before a vitamin shows any effect?
The hair cycle is slow, so it's worth thinking in months. In telogen effluvium even the shedding itself follows the trigger with a two to three month delay, and regrowth happens on a similar timescale. Asghar 2020 Any change seen in the first few weeks is more likely normal day-to-day variation.
What can be taken after childbirth and while breastfeeding?
Postpartum shedding is typically telogen gravidarum: it appears roughly three months after childbirth, and it's a form of acute telogen effluvium. Asghar 2020 Products taken during pregnancy and breastfeeding, though, are a genuine medical question, because active ingredients reach the fetus and breast milk. Discuss this with your doctor.
Can hair vitamins be given to children?
In a child, hair loss on its own is a symptom that needs a workup, because the balance of likely causes differs from an adult's: fungal scalp infection, alopecia areata, traction hair loss or hair pulling. Diagnosis is the first step here.
Do women and men need different vitamins?
The nutrient is the same, the likelihoods differ. In women, iron deficiency is much more common because of menstruation, so measuring ferritin gives more there. Almohanna 2019 In men, pattern hair loss starts earlier and more often, so there the cause of shedding typically lies elsewhere.
Can a vitamin cause hair loss?
In overdose, yes. Sustained high intake of vitamin A can cause hair loss, and the upper intake level set for adults is 10,000 IU of preformed vitamin A per day. Almohanna 2019 For selenium, intake above 400 micrograms a day can cause toxicity, one symptom of which is hair loss. Almohanna 2019 This matters most with combined products, because taking several boxes at once adds up.
Which blood tests are worth requesting?
For a hair loss workup, the usual starting point is a complete blood count, ferritin, TSH and vitamin D level. For women, hormone status can also come into play if there's another sign pointing to it: irregular cycle, increased hair growth elsewhere, acne. The exact list is put together by your GP or dermatologist based on your symptoms.
Sources
The quotes are from the original text of the cited publications. Where the evidence is contradictory, that's noted in the text too. This is information, not medical advice.
- Almohanna HM, Ahmed AA, Tsatalis JP, Tosti A. The Role of Vitamins and Minerals in Hair Loss: A Review. Dermatol Ther (Heidelb). 2019;9(1):51-70. PMC PMC6380979 · "Biotin deficiency causes hair loss, but there are no evidence-based data that supplementing biotin promotes hair growth." · "Severe biotin deficiency in healthy individuals eating a normal diet has never been reported." · "Data correlating TE and AGA with zinc level are not homogenous, and screening for zinc is not recommended." · "the definition of iron deficiency… has ranged from a serum ferritin concentration of ≤ 15 to < 70 μg/L" · "As a general rule, consuming too much or over-supplementing vitamin A can cause hair loss."
- Patel DP, Swink SM, Castelo-Soccio L. A Review of the Use of Biotin for Hair Loss. Skin Appendage Disord. 2017;3(3):166-169. PMID 28879195 · "We found 18 reported cases of biotin use for hair and nail changes. In all cases, patients receiving biotin supplementation had an underlying pathology for poor hair or nail growth." · "Despite its reputation, there is limited research to support the utility of biotin in healthy individuals."
- U.S. Food and Drug Administration. Testing for Biotin Interference in In Vitro Diagnostic Devices. Guidance for Industry. 2020. fda.gov · "biotin is used in hormone tests and tests for markers of cardiac health like troponin… Biotin levels in samples from patients who consume more than the recommended daily intake for biotin can cause falsely high or falsely low results, depending on the test principle. Incorrect test results may lead to inappropriate patient management or misdiagnosis."
- U.S. Food and Drug Administration. Biotin Interference with Troponin Lab Tests. Assays Subject to Biotin Interference. fda.gov · "the FDA has continued to receive adverse events reports indicating biotin interference caused falsely low troponin results."
- Olsen EA, Reed KB, Cacchio PB, Caudill L. Iron deficiency in female pattern hair loss, chronic telogen effluvium, and control groups. J Am Acad Dermatol. 2010. PMID 20947203 · "There was no statistically significant increase in the incidence of ID in premenopausal or postmenopausal women with FPHL or CTE versus control subjects." · "ID is common in women but not increased in patients with FPHL or CTE compared with control subjects."
- Trost LB, Bergfeld WF, Calogeras E. The diagnosis and treatment of iron deficiency and its potential relationship to hair loss. J Am Acad Dermatol. 2006. PMID 16635664 · "Currently, there is insufficient evidence to recommend universal screening for iron deficiency in patients with hair loss."
- Kil MS, Kim CW, Kim SS. Analysis of serum zinc and copper concentrations in hair loss. Ann Dermatol. 2013. PMC PMC3870206 · "the mean serum zinc was 84.33±22.88, significantly lower than the control group (97.94±21.05 µg/dl) (p=0.002)… However, this value is within the range of the reference value of the measuring equipment (70 to 130 µg/dl)" · "Zinc and copper are absorbed in the small intestine by the specialized ZnT (zinc transporter) channel, as well as by a common divalent cationic transporter."
- Park H, Kim CW, Kim SS, Park CW. The therapeutic effect and the changed serum zinc level after zinc supplementation in alopecia areata patients who had a low serum zinc level. Ann Dermatol. 2009. PMID 20523772 · "Oral zinc gluconate (50 mg/T/day) supplementation was given to alopecia areata patients without any other treatment for twelve weeks… Positive therapeutic effects were observed for 9 out of 15 patients (66.7%) although this was not statistically significant."
- Drake L, Reyes-Hadsall S, Martinez J, Heinrich C, Huang K, Mostaghimi A. Evaluation of the Safety and Effectiveness of Nutritional Supplements for Treating Hair Loss: A Systematic Review. JAMA Dermatol. 2023;159(1):79-86. PMID 36449274 · "30 articles were included: 17 randomized clinical trials (RCTs), 11 clinical studies (non-RCT), and 2 case series studies… Adverse effects were rare and mild for all the therapies evaluated." · "The findings of this systematic review should be interpreted in the context of each study's design; however, this work suggests a potential role for nutritional supplements in the treatment of hair loss. Physicians should engage in shared decision-making by covering the potential risks and benefits of these treatments with patients experiencing hair loss. Future research should focus on larger RCTs with active comparators."
- Asghar F, Shamim N, Farooque U, Sheikh H, Aqeel R. Telogen Effluvium: A Review of the Literature. Cureus. 2020. PMC PMC7320655 · "Acute telogen effluvium is defined as hair shedding lasting for less than six months. Generally, hair loss occurs two to three months after the trigger exposure… Acute telogen effluvium usually undergoes remission in around 95% of cases." · "Severe protein, fatty acid and zinc deficiency, chronic starvation, and caloric restriction can lead to telogen effluvium."
- Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods. EUR-Lex · "Biotin contributes to the maintenance of normal hair." · "Zinc contributes to the maintenance of normal hair." · "Selenium contributes to the maintenance of normal hair." · "Copper contributes to normal hair pigmentation." In the current consolidated text, these are the four claims listed for hair.
- Dhurat R, Sukesh MS, Avhad G, Dandale A, Pal A, Pund P. A randomized evaluator blinded study of effect of microneedling in androgenetic alopecia: a pilot study. Int J Trichology. 2013. PMC PMC3746236 · "After randomization one group was offered weekly microneedling treatment with twice daily 5% minoxidil lotion (Microneedling group); other group was given only 5% minoxidil lotion… The mean change in hair count at week 12 was significantly greater for the Microneedling group compared to the Minoxidil group." The device was a dermaroller, and both groups received minoxidil.