Supplements for Hair Loss: What Helps Hair Grow, What Doesn't, and What to Test First

The short version

• The medicines come first: minoxidil on the scalp, and finasteride tablets for men, grew more hair than placebo in pooled trials. A Grade A (Adil 2017; van Zuuren 2016).
• Multi-ingredient hair formulas: a little less shedding in pooled trials of branded products; total hair count didn't change. B Grade B (Alanazi 2026).
• Pumpkin seed oil and saw palmetto: small, short, mostly positive trials in pattern hair loss. C Grade C (Cho 2014; Evron 2020).
• Biotin: no better than placebo in its best trial, and high doses throw off blood tests. C Grade C (Yelich 2024; Moerman 2022).
• Iron, vitamin D and zinc: low levels go with hair loss, but no placebo-controlled trial shows the pills regrow hair. Test first. C Grade C (Treister-Goltzman 2022; Chen 2024; Wu 2025).
• Rosemary oil, on the scalp: no different from a weak minoxidil solution in one trial without placebo. C Grade C (Panahi 2015).

What kind of hair loss do you have?

The cause decides what helps. A 2024 review for family doctors sorts non-scarring hair loss into three groups (Dakkak 2024):

• Pattern hair loss (androgenetic alopecia) is the most common and mostly inherited. Minoxidil is the first-line treatment, and finasteride is an option for men.
• Shedding (telogen effluvium: many hairs enter the resting phase at once, then fall) is spread out and usually settles once the trigger, such as stress, has passed. Hair loss is common after big weight loss: 57% of people lost hair after weight-loss surgery in 18 studies (2,538 people), more often younger people and those low in folic acid or ferritin (Zhang 2021). On GLP-1 drugs, hair loss was about 3 times as likely as on placebo, with 3.9% of users affected (Cheng 2026); see our guide to supplements on GLP-1 medicines.
• Patchy hair loss (alopecia areata, an autoimmune condition) is often temporary; a dermatologist may use steroid injections or immune-calming pills.

What is the best supplement for hair growth?

No supplement has evidence as strong as the medicines. In pooled trials, scalp minoxidil (men and women) and finasteride (men) beat placebo (Adil 2017). In women, minoxidil made moderate to marked regrowth about twice as likely as placebo across 6 trials (van Zuuren 2016). Minoxidil tablets showed no difference in hair density from the scalp liquid in 4 trials (279 people) but caused unwanted body hair about twice as often, grade B (Sobral 2025). A doctor or dermatologist picks the form and dose.

Among supplements, pooled trials in pattern hair loss favor pumpkin seed oil, tocotrienols, an apple extract and some branded blends over placebo, with few side effects (Zhou 2025; Drake 2023). Most trials were small and short.

Does biotin help hair growth?

C Grade C for no clear benefit. Only 3 studies of biotin pills for hair turned up in a 2024 review. The strongest, double-blind and placebo-controlled, found no difference in hair growth; the other two had a high risk of bias and no striking result (Yelich 2024). In 18 case reports where biotin helped, every person had an underlying cause such as a deficiency, which the authors called uncommon (Patel 2017).

The real risk is to your lab results. High-dose biotin can push thyroid, hormone, ferritin, vitamin D and troponin (heart attack) results falsely up or down (Moerman 2022), and the FDA warns about falsely low troponin. See does biotin affect thyroid and troponin tests?, and mention biotin whenever you have blood taken.

Does iron help hair loss in women?

C Grade C. Low iron is linked to hair loss in women, but we found no placebo-controlled trial of iron alone for regrowth (one older double-blind study combined iron with L-lysine for shedding) (Rushton 2002). Across 36 studies (10,029 people), women losing hair without scarring had ferritin (stored iron) levels below those of women who weren't, and about 1 in 5 had very low ferritin (Treister-Goltzman 2022). At one clinic, 5 of 194 women with long-lasting shedding had low ferritin and no other cause; iron raised their ferritin, but none stopped shedding (Sinclair 2002). Our hair loss page says moderate; we grade C because these are links, not trials.

Ask for a ferritin test; if it's low, your clinician sets the amount and rechecks it. Upper limit for adults: 45 mg a day; take more only with blood tests or your clinician's advice (NIH ODS; upper-limit calculator).

Do vitamin D and zinc help hair loss?

C Grade C, as links only. In 23 studies (3,374 patients, 7,296 controls), people with non-scarring hair loss had lower vitamin D and were about 3 times as likely to be deficient (Chen 2024). In alopecia areata, vitamin D and zinc were both lower than in healthy people across 34 papers (Wu 2025). We found no placebo-controlled trial of vitamin D pills for regrowth. In 15 people with alopecia areata and low zinc, twelve weeks of zinc gluconate raised zinc levels and 9 improved, which was not statistically significant, with no comparison group (Park 2009).

Reviewers still want large placebo trials in deficient people (Almohanna 2019), so test rather than guess. Upper limits for adults: zinc 40 mg and vitamin D 4,000 IU a day (NIH ODS; upper-limit calculator).

Do saw palmetto and pumpkin seed oil help pattern hair loss?

C Grade C for each: small trials, mostly in men, mostly positive.

• Pumpkin seed oil. Men with pattern hair loss (76 in the trial) who took 400 mg a day for 24 weeks saw average hair counts climb 40%, versus 10% on placebo, with side effects no different (Cho 2014). We found no second placebo trial.
• Saw palmetto. A 2020 review counted 5 trials and 2 cohorts of saw palmetto pills and scalp products; results leaned positive, yet the authors found no robust high-quality data (Evron 2020). In a 2-year study with no placebo, more hair grew in 38% of men taking 320 mg of saw palmetto daily and 68% of men on finasteride (Rossi 2012). In a 180-day trial of one company's extract, 60 adults with thinning hair gained more terminal hairs than on placebo (Ablon 2026).

Do multi-ingredient hair supplements work?

B Grade B for a small drop in shedding. A 2026 meta-analysis pooled 14 studies (967 adults) of branded oral hair formulas, most lasting 12 weeks to 12 months. Against placebo, people had fewer resting-phase hairs, more growing-phase hairs and fewer hairs out on a pull test, but total hair count did not differ significantly (Alanazi 2026). In one trial, a marine protein supplement raised terminal hairs and cut shedding over 90 days in women with thinning hair (Ablon 2015). Each formula has only a few trials, and the reviewers asked for independent ones, so this is not grade A.

Do omega-3s, tocotrienols, collagen or silica help?

C Grade C for each, one small trial apiece.

• Omega-3 and omega-6 with antioxidants: 120 women taking it for 6 months had better hair density on photos and fewer resting hairs than a control group (Le Floc'h 2015).
• Tocotrienols (a form of vitamin E): 38 volunteers with hair loss took 100 mg of mixed tocotrienols a day or placebo for 8 months; hair numbers rose 34.5% against a 0.1% fall (Beoy 2010).
• Collagen peptides: 114 women aged 20 to 50 with self-reported thinning took 1,000 mg a day or placebo for 24 weeks, and hair diameter increased (Hwang 2026). We found no collagen trial that measured hair loss itself.
• Silica: in 48 women with fine hair, a daily silicon supplement (choline-stabilized orthosilicic acid) for 9 months lost less hair strength than placebo, and hair got thicker from baseline; the trial did not measure hair loss (Wickett 2007).

Does rosemary oil work as well as minoxidil?

C Grade C, on the scalp only. In the one head-to-head trial, 100 people with pattern hair loss used rosemary oil or a weak minoxidil solution for 6 months. Neither group's hair count had moved at 3 months; by 6 months both had more hair, with no significant difference, and itching was more frequent on minoxidil (Panahi 2015). With no placebo group, which works better is unresolved.

Caffeine scalp liquids rate the same, C Grade C. In an open-label trial of 210 men, growing hairs rose by similar amounts with caffeine and a stronger minoxidil solution over 6 months (Dhurat 2017), and a 2025 review of 9 trials favored caffeine but rated the evidence low or very low in 6 (Szendzielorz 2025).

What we'd skip

• Biotin for hair, unless a doctor finds a deficiency. Its best placebo trial was negative, and it can make blood tests wrong (Yelich 2024; Moerman 2022).
• Iron, zinc or vitamin D without a blood test. The evidence is a link with deficiency, and a 2002 review warns that too much of a nutrient can itself cause hair loss when no deficiency has been shown (Rushton 2002).
• Extra selenium or vitamin A "for hair". Too much of either makes hair fall out (see below) (MacFarquhar 2010; Cheruvattath 2006).
• Swallowing rosemary or other essential oils. Rosemary is one of 11 plant oils described as able to trigger seizures (Burkhard 1999).

Safety and interactions

• Biotin and lab tests. Before a blood draw, say if you take biotin, even in a multivitamin; with chest pain, tell the emergency team (Moerman 2022; biotin and lab tests).
• Selenium. A liquid supplement found to hold 200 times its labeled selenium made 201 people ill in 10 states; 72% lost hair, and in 29% the hair loss lasted 90 days or more (MacFarquhar 2010). Upper limit for adults: 400 mcg a day (NIH ODS).
• Vitamin A. In a case report, a 60-year-old man taking large doses developed hair loss, nail changes and liver damage that needed a transplant (Cheruvattath 2006). Upper limit for adults: 3,000 mcg (10,000 IU) a day of preformed vitamin A (NIH ODS).
• Saw palmetto. Across 26 trials and other reports, side effects were mild and about as common as on placebo, and no drug interactions were reported (Agbabiaka 2009). It may be unsafe in pregnancy or breastfeeding (NCCIH). On finasteride or a similar drug, ask your prescriber first.
• Pumpkin seed oil and branded formulas: side effects matched placebo or were rare and mild (Cho 2014; Drake 2023). No interaction studies were found. Hair formulas often repeat zinc, selenium and vitamin A, so check your stack against the upper limits.
• Creatine did not change DHT or hair measures against placebo in the 38 weight-trained men who finished a 12-week trial. C Grade C (Lak 2025).

When to see a doctor

• Soon: sudden, rapid or patchy hair loss; a red, scaly, sore or scarred scalp; or hair loss along with tiredness, weight change, feeling cold or heavy periods. Thyroid disease, low iron and alopecia areata need a diagnosis (Dakkak 2024).
• Shedding after a new medicine, weight-loss surgery or a GLP-1 drug. Don't stop a prescribed medicine on your own; ask the prescriber or pharmacist.
• Pregnancy, breastfeeding, after childbirth or under 18: ask a clinician, such as your doctor or midwife, first.

FAQ

What's the best supplement for hair growth? No supplement has evidence as strong as minoxidil or finasteride (grade A). Branded multi-ingredient formulas cut shedding a little (grade B).

Does biotin help hair growth? Not unless you are deficient: it did no better than placebo in its best trial (grade C), and high doses can skew thyroid and troponin tests.

What vitamins help hair loss in women? Get tested first. Low ferritin and low vitamin D are common in women with hair loss, but no placebo-controlled trial shows the pills regrow hair (grade C).

Is rosemary oil as good as minoxidil? Unresolved. In one 6-month scalp trial both groups gained hair with no significant difference, and there was no placebo (grade C).

Does collagen help hair grow? One trial of 114 women found thicker hair shafts after 24 weeks (grade C); no trial has tested collagen for hair loss.

Can supplements cause hair loss? Yes: too much selenium or vitamin A. Creatine did not change hair or DHT in a 12-week trial (grade C).

Related pages

• Hair loss findings · Hair health findings · Hair loss protocol
• Iron · Zinc · Vitamin D · Pumpkin seed · Collagen · Vitamin E · Silica
• Does biotin affect thyroid and troponin tests? · Supplements on GLP-1 medicines
• Upper-limit calculator · How we grade evidence (A to D)

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