Hair Growth Supplements: Which Ones Have Evidence?

How do the main hair growth supplements compare?

These are the options people ask about most. “Evidence” here means human studies of the product or ingredient for hair loss, not marketing claims or before-and-after photos.

Buying options: Nutrafol ⁠↓ Viviscal ⁠↓

Prices are before tax and shipping, checked November 10, 2026, except the Nutrafol storefront’s, checked November 8; ranges run from the longest subscription to a one-time purchase. Low-cost options vary by brand and pack size. Sources: Nutrafol, Viviscal Women’s, Viviscal Men’s and Nature’s Bounty product pages.

What should you check before buying a hair supplement?

The cause matters more than the brand. Shedding that starts a few months after illness, childbirth, surgery or rapid weight loss is often telogen effluvium, which usually settles once the trigger passes. Gradual pattern thinning tends to progress. Patches, scalp pain or redness need an examination.

If your history suggests it, a provider may check iron stores, vitamin D, thyroid function or a blood count. The American Academy of Dermatology advises taking biotin, iron or zinc only when a blood test shows a deficiency, and warns that supplementing normal levels can be harmful.

Our guides to hair thinning in women and hair loss in men explain the common patterns and what to bring to an appointment.

Do hair growth supplements actually work?

Some can help some people, modestly. The most useful summary is a 2023 JAMA Dermatology systematic review of 30 studies, 17 of them randomized trials, in people without a known nutritional deficiency. It found the highest-quality evidence of potential benefit for products including Viviscal, Nutrafol, Lamdapil and Pantogar, and for ingredients such as pumpkin seed oil, zinc and tocotrienols. Side effects were rare and mild.

A 2026 network meta-analysis of 19 randomized trials in 1,658 people with pattern hair loss (androgenetic alopecia) came to a similar view: Nutrafol, apple extract, tocotrienols and pumpkin seed oil improved hair density compared with placebo, and all supplements studied were well tolerated.

Why the results deserve some caution

• The studies are small. The original Nutrafol women’s trial had 40 participants; the Viviscal women’s trial had 60.
• More hairs on a scan is not always a visible change. Trials count hairs in a small, marked patch of scalp. A statistically significant gain there may or may not show in the mirror.
• Follow-up is short. Three to six months says little about what happens over years of use.
• Manufacturers are closely involved. Most brand trials were funded by or run with the company, and few compare a supplement with minoxidil or finasteride.
• Many participants had mild or self-reported thinning, rather than a confirmed diagnosis.

The JAMA reviewers called for larger trials against proven treatments. Until those exist, treat a supplement as a trial for mild thinning or an add-on to treatment, not a substitute for a diagnosis or a proven medicine.

Nutrafol: premium blends with formula-specific research

Nutrafol uses standardized plant extracts, including ashwagandha, saw palmetto, curcumin and tocotrienols, in separate formulas for women, men, menopause (Women’s Balance) and postpartum. The current Nutrafol Women formula uses vegan ingredients and no longer contains biotin, which matters if you have regular blood tests.

Match each study to the formula it tested. In a 2018 trial run with the company, 26 women took the original Nutrafol Women formula and 14 took a placebo for six months. Terminal and vellus hair counts rose significantly at 90 and 180 days compared with placebo. That original formula contained marine collagen, biotin and keratin, which the current Women formula leaves out. A 2021 placebo-controlled trial of Women’s Balance in perimenopausal to postmenopausal women (40 on the supplement, 30 on placebo) also reported higher hair counts at 90 and 180 days.

The current Women formula was tested in a 2026 study funded by Nutrafol’s maker, in which 180 women took one of four Nutrafol formulas for six months and 150 finished. Hair growth rate and hair counts rose compared with each woman’s starting point. The study had no placebo group, so it cannot separate the supplement’s effect from other changes over time.

Best fit: mild thinning, a monthly cost you can keep up for at least six months, and a formula that suits your health and medicines. Women in menopause have a formula with its own placebo-controlled trial.

Check the ingredients against your health. Nutrafol Women lists ashwagandha, and other formulas may too, so read the label. The NIH’s complementary health center (NCCIH) says ashwagandha is not recommended for people with thyroid or autoimmune disorders, should be avoided during pregnancy and breastfeeding, may interact with some medicines, including those for diabetes, blood pressure, seizures and immune suppression, and has been linked to rare cases of liver injury. These are ingredient cautions, not findings about Nutrafol itself. Nutrafol makes a separate Postpartum formula that it describes as breastfeeding-friendly and OB-GYN-developed. If you are breastfeeding, review that exact label with your provider before starting; a manufacturer’s description does not establish that a product suits everyone.

Where to buy. The Real Growth Guarantee applies only to first-time subscribers on Nutrafol.com who buy six bottles by subscription within 180 days and complete check-ins in the Nutrafol app. Storefront and marketplace orders do not qualify, but the storefront lists lower three- and six-month prices.

Want the detail on formulas, subscriptions and the guarantee? Read our full Nutrafol review, or see how it compares in Nutrafol vs. minoxidil.

Viviscal: lower cost, older trials

Viviscal’s published trials tested its marine-protein formula. Today’s labels list a marine Collagen Complex with oyster extract, which the brand says has been studied in 10 clinical trials. The two versions differ: the women’s supplement adds 240 mcg of biotin, 20 mg of iron and 22 mg of zinc, while the men’s has zinc, vitamin C, horsetail and flax seed but no biotin, iron or niacin. Both take two tablets a day.

Cost. On Viviscal.com, a one-time month costs $40; subscriptions cost $36 a month, $96 every three months or $180 every six, which works out to $30 a month. Amazon’s Subscribe & Save also discounts repeat orders. Either way, it costs roughly half as much as Nutrafol.

In a 2015 trial funded by the maker, 60 women with self-perceived thinning took an extra-strength marine-protein supplement or placebo for 90 days. The supplement group had more terminal hairs and less shedding. A 2016 trial in men with diagnosed pattern hair loss reported increases in hair count and density after 180 days. Both tested earlier versions of the formula, so compare the current label.

Best fit: a studied option at a lower monthly cost. Both versions contain oyster extract, a shellfish ingredient, and neither is vegan.

Biotin gummies: popular, but rarely the answer

Biotin is the most common “hair vitamin.” Popular products such as Nature’s Bounty Hair, Skin & Nails list 2,500 to 5,000 mcg per serving, while adults need about 30 mcg a day, and most people get enough from food.

A 2017 review found 18 reported cases in which biotin helped hair or nails, and every one involved an underlying problem such as a deficiency or a rare hair disorder. The NIH Office of Dietary Supplements says there is little scientific evidence for biotin’s hair, skin and nail claims.

The larger concern is testing. The FDA says biotin in supplements can significantly interfere with certain lab tests, including falsely low troponin results used to help diagnose heart attacks. Thyroid tests can also be affected. Tell anyone ordering blood work that you take biotin.

Best fit: a deficiency found on a blood test, with the product and dose your provider suggests. Without one, a high-dose beauty supplement has little evidence for hair growth.

Saw palmetto and pumpkin seed oil

Both are thought to act on the hormone pathway behind pattern hair loss. Saw palmetto is also one of the ingredients in Nutrafol.

Saw palmetto. A 2020 systematic review found five randomized trials and two cohort studies of oral or topical products containing 100 to 320 mg of saw palmetto, with positive effects and no serious side effects. The products and outcomes varied, and the reviewers noted that high-quality data are lacking.

Pumpkin seed oil. In a 2014 trial, 76 men with mild to moderate pattern hair loss took 400 mg a day of a pumpkin seed oil product or placebo for 24 weeks. Hair counts rose 40% with the product and 10% with placebo. It was a single study supported by a company grant.

Either can be a low-cost experiment for mild pattern thinning. Neither has the evidence behind finasteride or minoxidil, and the same is true of rosemary oil.

How to compare hair supplement labels before you buy

The front of the bottle sells the product; the Supplement Facts panel shows what you would actually take. Five checks before you order:

• Daily serving. The amounts listed usually assume the full serving: four capsules a day for Nutrafol, two tablets for Viviscal. Work out the monthly cost at that serving.
• Overlap. Add up biotin, zinc, vitamin A, selenium and iron across everything you take, including a multivitamin. Hair formulas often repeat nutrients you already get.
• Allergens and diet. Collagen and marine ingredients can come from fish or shellfish; Viviscal, for example, contains oyster extract. Check the label if you have an allergy or eat a plant-based diet.
• Subscription terms. Compare the subscription price with the one-time price, and check how to pause or cancel and what any guarantee covers.
• Quality seals. The FDA does not approve supplements for safety or effectiveness before they are sold. Seals from groups such as USP or NSF show a product was properly made and contains what the label lists, but the NIH notes they do not guarantee that a product is safe or effective.

Which hair supplement fits your situation?

Match the product to the cause and to your budget for six months, not just the first bottle.

Are hair supplements safe?

Trials report few side effects, but they are small and short. The practical risks come from doses, combinations and timing.

• Biotin and blood tests. Biotin above recommended amounts can cause incorrect results in some lab tests. Mention it before any blood work.
• Too much vitamin A or selenium can itself cause hair loss, according to a review of vitamins and minerals in hair loss. The NIH lists hair loss among the signs of too much selenium; the adult upper limit is 400 mcg a day from all sources. Adding a hair supplement to a multivitamin can push totals higher than you expect.
• Iron and zinc belong in your routine only when a test shows you need them.
• Pregnancy, breastfeeding, trying to conceive, other medicines or a medical condition: ask a provider or pharmacist before starting. Botanical blends are rarely studied in these groups.

How long do hair growth supplements take to work?

Judge a branded hair supplement at three months and decide at six. Hair grows slowly, and the brand trials measured results at 90 and 180 days. If you are correcting a deficiency found on a blood test, follow the retest plan your provider sets instead.

• Take photos of your part, temples and crown every month in the same light and position.
• Note whether shedding in the shower or brush is changing.
• Start one product at a time so you can tell what made the difference.
• Stop a branded supplement if you see no change at six months, or sooner if you have side effects.

If thinning keeps progressing, a dermatology visit is usually a better next step than a second supplement.

Hair growth supplements: common questions