Best Hair Loss Vitamins and Supplements for Men (Evidence-Based)

The supplement industry has made a fortune selling men false hope in capsule form. Biotin gummies, keratin powders, “hair growth formulas” with 47 ingredients — most of it is expensive noise.

But some supplements actually have clinical backing. This is a ranked list of 7 that are worth your money, with the evidence explained clearly.

Quick caveat: if you have male pattern baldness (androgenetic alopecia), no supplement fixes it. DHT is the driver and supplements don’t block DHT the way finasteride does. What supplements can do is address nutritional deficiencies that accelerate shedding and support the conditions for healthy follicle function.

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Ranking Methodology

Each supplement is scored on:

• Evidence quality (peer-reviewed studies vs anecdote)
• Mechanism (does the biology actually make sense?)
• Effect size (how much difference does it realistically make?)
• Value (cost vs. benefit)

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#1 — Vitamin D

Why it matters: Vitamin D receptors are present in hair follicles. Multiple studies link vitamin D deficiency to telogen effluvium (stress-related shedding) and alopecia areata. A 2013 study in Dermatology Online Journal found significantly lower vitamin D levels in women with hair loss compared to controls. Similar patterns appear in male studies.

Who’s deficient: Probably you, if you live in the UK. Vitamin D deficiency affects an estimated 1 in 5 adults in the UK due to low sunlight. The NHS recommends supplementation during autumn and winter for everyone.

Dosage: The NHS recommends 10 mcg (400 IU) for maintenance. For correcting a deficiency, 25–50 mcg (1,000–2,000 IU) is commonly used — confirm with a blood test.

Evidence score: 8/10

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#2 — Iron (Ferritin)

Why it matters: Low ferritin (stored iron) is one of the most commonly missed causes of hair shedding in men. Hair follicles are among the most metabolically active cells in the body and require adequate iron for healthy cycling. A 2006 review in the Journal of American Academy of Dermatology concluded that ferritin levels below 30 ng/mL can cause or worsen hair shedding.

Who’s deficient: Men who don’t eat much red meat, vegetarians, vegans, and men with undiagnosed GI issues. Less common than in women but far more prevalent than most people assume.

Get tested first. Don’t supplement iron without a blood test showing low ferritin. Excess iron is toxic and supplementing unnecessarily won’t help — and might cause issues.

Dosage: If deficient, 200–300mg elemental iron daily (as ferrous sulphate or ferrous fumarate) under medical guidance.

Evidence score: 8/10

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#3 — Zinc

Why it matters: Zinc is involved in the hair growth cycle and inhibits the enzyme 5-alpha reductase — the same enzyme that converts testosterone to DHT. A 2013 study in Annals of Dermatology found significantly lower zinc levels in men with androgenetic alopecia compared to controls, and zinc supplementation improved hair density scores.

Important: Zinc’s DHT-blocking effect is modest compared to finasteride. Don’t expect dramatic reversal. But if you’re deficient, correcting it can noticeably reduce shedding.

Dosage: 25–50mg elemental zinc per day. Don’t go over 40mg long-term without medical guidance — excess zinc can deplete copper.

Evidence score: 6/10

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#4 — Saw Palmetto

Why it matters: Saw palmetto is a plant extract that inhibits 5-alpha reductase, similar mechanically to finasteride but with weaker potency. A 2002 study in Journal of Alternative and Complementary Medicine found it improved hair counts in 60% of participants with mild-to-moderate hair loss. A 2020 Cochrane-adjacent review found it statistically significant for hair density improvement.

Realistic expectations: It’s not finasteride. Studies show roughly 60% efficacy vs the ~86% seen with finasteride. But it’s available without prescription, causes minimal side effects, and is a reasonable option for men not ready for medication.

Dosage: 320mg/day of standardised extract (85–95% fatty acids).

Evidence score: 6/10

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#5 — Collagen Peptides

Why it matters: Hair is primarily made of a protein called keratin, which contains several amino acids — particularly glycine and proline — that are also abundant in collagen. Some research suggests hydrolysed collagen peptides improve hair thickness and reduce shedding. A 2021 double-blind study in Journal of Cosmetic Dermatology found oral collagen supplementation significantly improved hair thickness and reduced shedding after 6 months.

Caveat: This is more of a “hair health” supplement than a “hair loss” treatment. It won’t stop DHT-driven miniaturisation but may improve the condition of existing hair.

Dosage: 10–15g hydrolysed collagen peptides daily.

Evidence score: 5/10

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#6 — Pumpkin Seed Oil

Why it matters: Pumpkin seed oil contains phytosterols that may inhibit 5-alpha reductase. A standout 2014 randomised controlled trial published in Evidence-Based Complementary and Alternative Medicine found that 400mg/day of pumpkin seed oil significantly increased hair count over 24 weeks compared to placebo — with a 40% increase in hair count in the treatment group.

This is one of the more impressive supplement studies and is often cited as the most compelling evidence for a non-prescription DHT blocker.

Dosage: 400mg/day (from the trial). Available as capsules or as the actual oil.

Evidence score: 6/10

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#7 — B Vitamin Complex (Not Just Biotin)

Why it matters: B vitamins as a group — particularly B12, folate (B9), and niacin (B3) — are involved in red blood cell production and energy metabolism in follicle cells. Deficiencies in B12 and folate are associated with telogen effluvium. Unlike biotin in isolation, a B-complex addresses multiple potential gaps.

The biotin reality check: If biotin is already adequate (which it is for most people eating a varied diet), more biotin does nothing for hair. But a comprehensive B-complex addressing potential B12 or folate shortfalls can help men whose shedding has a nutritional component.

Read our full article on biotin for hair loss for the detailed breakdown.

Dosage: One B-complex daily. Look for methylated forms of B12 and folate for better absorption.

Evidence score: 5/10

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Supplements That Didn’t Make the Cut

Biotin alone: Unless you’re deficient. Full debunking in our biotin article.

Keratin supplements: No meaningful clinical evidence for oral keratin improving hair growth.

“Hair growth formula” blends: Usually biotin + collagen + random extracts at sub-therapeutic doses. You can do better by buying the individual ingredients.

Rosemary oil (supplements): Topical rosemary oil has some evidence as a minoxidil alternative. Oral supplements don’t deliver the same local concentration. Topical application is covered in other articles.

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Building a Sensible Supplement Stack

If you’re building a stack focused on addressing potential deficiencies and supporting hair health:

Essential first (get tested):

• Vitamin D — most UK men need this
• Iron/ferritin — blood test before supplementing

Add if budget allows:

• Zinc (if not eating much red meat/shellfish)
• Pumpkin seed oil (solid evidence, low side effects)
• Saw palmetto (if not on finasteride)

Skip or deprioritise:

• Biotin in isolation
• Expensive branded “hair” supplements

Monthly cost estimate for the above stack: £20–40

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The Most Important Thing to Understand

Supplements address nutritional deficiencies and provide marginal support. They do not stop androgenetic alopecia.

If you’re losing your hair due to DHT (which accounts for ~95% of male hair loss), the treatments that actually work are:

1. Finasteride — see a doctor or use an online clinic like Manual or Treated.com
2. Minoxidil — available OTC
3. The combination of both — the gold standard

Supplements are the supporting cast. Finasteride and minoxidil are the leads.

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Bottom Line

The 7 supplements above have genuine research behind them. Vitamin D and iron address the most common deficiencies linked to hair shedding. Zinc and saw palmetto offer modest DHT-related benefits. Pumpkin seed oil has the strongest supplement trial evidence. Collagen and B-complex provide broader hair health support.

None of them will regrow a hairline. But if you’re on finasteride and minoxidil and want to optimise everything else, a targeted supplement stack is a sensible adjunct. Just don’t let it become an expensive substitute for actual treatment.