Last updated: March 2026

Biotin (vitamin B7) is essential for healthy hair, but supplementation only improves growth in people with an underlying biotin deficiency — which is rare in healthy men eating a normal diet. A 2017 systematic review of all published biotin research found that every case where supplementation helped involved an existing pathology or deficiency. For the vast majority of men, biotin supplements won't make your beard grow faster or thicker.

Search "biotin for beard growth" and you'll find thousands of results telling you the same thing: take this vitamin and watch your beard fill in. Supplement brands have turned biotin into a $2.6 billion industry, and bearded men are a huge part of that market.

Here's the problem: the science doesn't support the hype. Not even close.

At stubble + 'stache — the skincare brand and Certified B Corp™ that's been making products specifically for men with facial hair since 2013 — we'd rather give you the honest answer than sell you on false hope.

So let's dig into what dermatology research actually says about biotin and your beard, why most men are throwing money away on supplements they don't need, and what the evidence suggests might actually help instead.

What Is Biotin, and Why Does Everyone Think It Grows Hair?

Biotin is vitamin B7, a water-soluble B vitamin your body uses to metabolize fatty acids, carbohydrates, and amino acids. It's sometimes called vitamin H — from the German words "Haar und Haut" (hair and skin) — which might explain how it got its reputation as a hair-growth miracle.

Your body does need biotin for healthy hair. It's a necessary cofactor for enzymes located in hair roots, and people who are genuinely biotin-deficient can develop hair loss, brittle nails, and skin rashes. That much is well-established.

The leap that supplement companies make is this: if a deficiency causes hair loss, then extra biotin must cause extra hair growth. That logic sounds reasonable. It's also wrong. "Required for normal function" and "more is better" are very different claims — and the research only supports the first one.

What Does the Research Actually Say?

In short: biotin supplementation has never been shown to improve hair growth in healthy, non-deficient people. Every published case where it actually helped involved an underlying condition. Here's the evidence.

The 2017 Systematic Review

The most comprehensive analysis of biotin and hair growth was published by Patel et al. in 2017 in the journal Skin Appendage Disorders. The researchers reviewed all available literature on biotin supplementation for hair and nail growth. Their finding was striking: across every case where biotin actually improved hair outcomes, the patient had an underlying condition — either a documented biotin deficiency, a genetic disorder affecting biotin metabolism, or another pathology.

Not a single controlled study showed benefits for healthy people who simply wanted more hair growth. Zero.

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. doi:10.1159/000462981 · PubMed: 28879195

The 2019 Vitamins and Hair Loss Review

A broader 2019 review by Almohanna et al. in Dermatology and Therapy examined the role of all vitamins and minerals in hair loss. The authors confirmed that while micronutrient deficiencies (including biotin, zinc, vitamin D, and iron) can contribute to hair loss, supplementation in people who aren't deficient doesn't show clear benefits.

The review specifically noted that large-scale, placebo-controlled trials are still needed to establish whether supplementation helps even in people with documented deficiencies and hair loss. The evidence base is that thin.

Almohanna HM, Ahmed AA, Tsatalis JP, et al. The role of vitamins and minerals in hair loss: a review. Dermatol Ther (Heidelb). 2019;9(1):51-70. doi:10.1007/s13555-018-0278-6 · PubMed: 30547302

Are You Actually Biotin-Deficient? (Probably Not)

True biotin deficiency is rare in healthy adults. The recommended daily intake is 30 mcg, and a balanced Western diet typically provides 35–70 mcg per day — well above what you need. Most men get plenty of biotin from food without even trying.

Biotin is found in a wide range of common foods: eggs, meat, fish, nuts, dairy, seeds, and some vegetables. Your gut bacteria also produce biotin. For most men eating a reasonably varied diet, deficiency simply isn't a concern.

There are legitimate risk factors for biotin deficiency — chronic alcohol use, certain genetic disorders (like biotinidase deficiency), inflammatory bowel disease, and prolonged use of certain medications including some anti-seizure drugs. But these are specific conditions, not the general population buying beard gummies off Instagram.

The Part Nobody Talks About: Biotin Can Mess With Your Lab Tests

High-dose biotin supplements can interfere with laboratory blood tests — and the results can be dangerous.

The FDA issued a safety communication in 2017 (updated in 2019) warning that biotin can cause falsely high or falsely low results on tests including thyroid function, troponin (used to detect heart attacks), hormone levels, vitamin D, and PSA tests.

FDA Safety Communication: Biotin May Interfere with Lab Tests (November 2017, updated 2019)

Many "beard growth" supplements contain 5,000–10,000 mcg of biotin — up to 333 times the recommended daily intake. At those doses, the interference with lab tests is a real clinical concern. A falsely normal troponin result could mean a heart attack gets missed. A falsely abnormal thyroid result could put you on medication you don't need.

If you're taking biotin supplements and have blood work scheduled, tell your doctor and stop supplementation at least 72 hours before testing.

Could a Different Deficiency Be Affecting Your Beard?

While biotin deficiency is rare, deficiencies in zinc, vitamin D, and iron are more common and have stronger associations with hair health. If you suspect a nutritional issue is affecting your beard, the answer isn't buying a supplement off the shelf — it's getting blood work done and working with your doctor.

The 2019 Almohanna review found more robust (though still limited) evidence connecting zinc, vitamin D, and iron levels to hair health. Unlike biotin, these deficiencies are relatively common — especially vitamin D deficiency, which affects an estimated 40% of American adults.

But here's the important nuance: even with these nutrients, the evidence supports correcting a deficiency, not mega-dosing for extra growth. Taking zinc supplements when your zinc levels are normal won't supercharge your beard any more than biotin will.

The responsible approach: if you think nutrition might be playing a role, get tested. A basic blood panel can check your levels of vitamin D, zinc, iron (ferritin), and thyroid function. Then you'll know whether supplementation actually makes sense for you.

For the full ingredient-by-ingredient breakdown — including which supplements might actually hurt your beard — read our complete beard growth supplements guide.

A Note on Topical Niacinamide vs. Oral Biotin

You might notice that Hydrate contains niacinamide (vitamin B3), and you might wonder if we're being hypocritical — criticizing one B vitamin while selling another. Fair question.

The difference is the delivery method and the evidence base. Niacinamide applied topically has published evidence for improving skin barrier function, reducing irritation, and supporting healthy skin — the foundation your beard grows from. It's not claiming to accelerate growth. It's creating the best possible environment for the hair you already grow.

Oral biotin supplementation for people who aren't deficient has no controlled evidence supporting improved hair growth. Those are fundamentally different claims with fundamentally different evidence behind them.

We're not selling you a beard growth miracle. We're selling you a daily moisturizer that takes care of the skin your beard grows from — with ingredients that have actual evidence behind them.

What Actually Helps Grow a Beard?

Beard growth is primarily determined by three things you can't change: genetics, hormones, and age. But for men looking to actively improve growth, there are approaches with stronger evidence than biotin.

Minoxidil is a topical treatment with clinical studies supporting its use for facial hair growth. It's the most evidence-backed option available for men who want to actively stimulate new growth. Read our full guide to minoxidil for beard growth →

Microneedling (dermarolling) has emerging evidence suggesting it can stimulate hair growth by triggering the wound healing response and increasing blood flow to follicles. Read our full dermarolling guide →

Overall health — sleep, nutrition, stress management, and exercise — all support healthy testosterone levels and hair growth. These aren't magic solutions, but they're the foundation everything else builds on.

And if your beard itches or flakes while you're growing it out, that's almost always a skin issue, not a hair issue. A solid skincare routine will do more for how your beard looks and feels than any supplement. Here's our guide to fixing beard itch →