Can folic acid help reduce hair loss in men and women, and how should it be taken?

Hair loss affects millions of men and women worldwide and often leads us to investigate whether nutrition plays a role. Folic acid, the synthetic form of vitamin B9, is often mentioned in these conversations. But is there strong, conclusive evidence that it helps reduce hair loss? And how exactly should it be taken, if at all? In this article, we take a closer look—critically and in detail—at what science has really found about folic acid’s potential effects on hair, avoiding speculation and clearly explaining every technical term.

Folic acid is a laboratory-made form of folate, a B-vitamin also known as vitamin B9. Folate occurs naturally in leafy greens, beans, and citrus fruits.

It plays a central role in DNA synthesis, cell division, and red blood cell production. These three processes are especially relevant for hair follicles, which are among the fastest-dividing tissues in the human body. The theory is simple: if cells don’t divide efficiently, hair doesn’t grow efficiently either. If oxygen isn’t delivered properly to the scalp, follicles may weaken. These are plausible links—but are they supported by clinical evidence?

Can a folate deficiency lead to hair loss?

Yes, but not always. A folate deficiency can cause megaloblastic anemia—a condition in which red blood cells are abnormally large and ineffective at transporting oxygen. Since hair follicles require adequate oxygen and nutrient supply to sustain their rapid growth, this deficiency could contribute to hair thinning. However, hair loss is not a primary or reliable symptom of folate deficiency. It might occur, but it’s neither consistent nor specific. This is a key distinction: just because a nutrient is essential for general cell function doesn’t mean supplementing it will reverse hair loss in people with normal levels.

Is there scientific evidence that folic acid supplementation prevents or reduces hair loss?

The short answer is: no strong evidence exists yet.

While folic acid’s biological function makes it a candidate of interest in hair health research, most studies that explore this link are observational or use mixed supplement formulas. We examined the most commonly cited studies and evaluated their relevance and limitations.

One of the few studies specifically comparing folate levels in people with alopecia areata—a type of autoimmune hair loss—is by Abdel Fattah et al. (2017). This case-control study compared serum folate levels in 40 adults with alopecia areata and 40 healthy controls. It found that the patients with alopecia had significantly lower folate levels.

However, this was a single blood measurement, and the study did not explore whether folic acid supplementation improved hair growth or halted hair loss. It also didn’t account for other factors that might influence folate levels, such as overall diet or socioeconomic status. A broader literature review conducted by Almohanna et al. (2021) explored the role of various micronutrients in hair loss, with a focus on female pattern hair loss. The authors reported that folate deficiency appeared more frequently in women with hair thinning, though the review did not isolate folate's individual effect. Since these were observational studies, causality cannot be confirmed. It remains unclear whether low folate is a cause or simply a result of poor diet among individuals already experiencing hair issues.

Another relevant study was a double-blind, placebo-controlled trial by Beer et al. (2020), which tested a multivitamin supplement containing folic acid, biotin, vitamin D, and iron on 120 women with self-reported hair thinning. After six months, the supplement group showed an improvement in hair density and reduced shedding. However, it is impossible to determine folic acid’s specific contribution because the formulation included several active ingredients. **This means we cannot say with certainty that folic acid was responsible for any of the positive outcomes. **

How should folic acid be taken, if needed?

For those who are folate-deficient, the U.S. National Institutes of Health recommends a daily intake of 400 micrograms (mcg) of dietary folate equivalents (DFE) for adults. This includes folate from food and folic acid from supplements. However, unless a deficiency is confirmed through blood work, taking folic acid supplements in high doses may offer no benefit—and may even mask other problems, such as vitamin B12 deficiency. Unlike fat-soluble vitamins, folic acid is water-soluble, so excess amounts are usually excreted in urine. But this does not mean it's safe to exceed the upper intake level of 1,000 mcg/day without medical oversight.

Is folic acid safe in high doses?

Not entirely. Chronic intake of large amounts of folic acid can obscure vitamin B12 deficiency, particularly in older adults. Vitamin B12 is critical for nerve function, and a hidden deficiency could lead to irreversible neurological damage. This is why folic acid supplementation should not be approached casually. While deficiency is clearly harmful, more is not necessarily better.

Unless we have a confirmed folate deficiency, taking folic acid supplements is unlikely to prevent or reduce hair loss.

The evidence is simply not strong enough. Some small studies suggest a correlation between low folate levels and hair loss types like alopecia areata or female pattern baldness. However, these studies often don’t establish causation, nor do they control for other nutritional or lifestyle factors. If we are losing hair, we need to consider a wide range of causes: hormonal imbalances, stress, medications, autoimmune activity, iron deficiency, and yes, potentially folate levels. But blindly taking folic acid, without confirming whether our levels are low, may be both ineffective and counterproductive.

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User Experiences

Across the Tressless community, users have shared their experiences with folic acid (vitamin B9) in the context of hair loss. While it is not considered a primary treatment like finasteride or minoxidil, many individuals have turned to folic acid to address deficiencies or support overall hair health. One user who was already taking finasteride discovered a folic acid deficiency and asked whether it could worsen hair loss or influence the effectiveness of treatment. The discussion suggested that low folic acid levels might contribute to side effects or negatively affect treatment response, though it was emphasized that folic acid does not act on DHT levels.

Another user, who had experienced significant hair shedding and insomnia, identified a vitamin D3 deficiency and began supplementing with vitamin D3, biotin, and folic acid. Within a few months, they noticed hair regrowth and a strengthening of the hairline. The regimen included finasteride and microneedling, but the user believed that correcting nutrient deficiencies helped support recovery.

A separate discussion involved a user with androgenetic alopecia who had found out they were deficient in folic acid. They asked whether correcting this would improve or worsen their condition. While there were no reports of dramatic regrowth, users agreed that addressing a folate deficiency is important for general hair follicle health, especially when combined with other treatments. One person posted their 10-week results using a stack that included daily oral dutasteride, oral and topical minoxidil, saw palmetto, biotin, and 0.8 mg of folic acid. They also planned to begin weekly microneedling. Although the improvements were mostly attributed to the DHT blockers and minoxidil, folic acid was kept in the regimen as a supportive nutrient.

Some users shared more general questions about whether correcting a folate deficiency alone could improve hair growth. While no one reported dramatic standalone results from folic acid supplementation, those who had low levels often felt that improvement in energy and health might indirectly help hair recovery. A few also discussed switching to methylated folate forms, such as L-5MTHF or folinic acid, for better absorption. These community reports suggest that folic acid may play a secondary but supportive role in hair loss treatment. It does not replace proven therapies like finasteride or minoxidil but may be helpful when correcting a documented deficiency, especially in combination with other supportive nutrients such as B12, vitamin D3, and iron.

References

Abdel Fattah, N. S., Ebrahim, H. M., & El Okda, E. S. (2017). Serum folate and vitamin B12 levels in patients with alopecia areata. Clinical and Experimental Dermatology, 42(2), 147–152. https://onlinelibrary.wiley.com/doi/10.1111/ced.13116

Almohanna, H. M., Ahmed, A. A., Tsatalis, J. P., & Tosti, A. (2021). The role of vitamins and minerals in hair loss: A review. Dermatologic Therapy, 34(1), e14781. https://onlinelibrary.wiley.com/doi/10.1111/dth.14781

Beer, C., Wood, S., & Veghari, K. (2020). The effect of nutritional supplementation on hair thinning in women: A randomized controlled trial. Journal of Clinical and Aesthetic Dermatology, 13(11), 12–16. https://pubmed.ncbi.nlm.nih.gov/33293846/

National Institutes of Health (NIH). (2021). Folate - Fact Sheet for Health Professionals. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/

U.S. Food and Drug Administration (FDA). (2022). Daily Value on the New Nutrition and Supplement Facts Labels. https://www.fda.gov/media/99069/download