Niacin
Niacin (Vitamin B3)
Severe deficiency (pellagra) causes alopecia. In a normal-diet adult, niacin supplementation does nothing for hair.
How Niacin works — and how well we know it
Niacin is required for NAD/NADP synthesis, central to cellular energy metabolism. Severe deficiency (pellagra) causes hair loss, dermatitis, and dementia — but deficiency is essentially eliminated in fortified-food populations.
oral
14–16 mg/day (RDA). Pharmacologic dyslipidemia doses 500–3,000 mg/day cause flushing and have no hair-loss indication.
Available as a dietary supplement. Pharmacologic doses prescribed for dyslipidemia. RDA 14–16 mg/day.
Patients with documented pellagra. Otherwise, no hair-loss indication.
Evidence distribution across 1 claims
Why the grade is D. Deficiency-only correction. No RCT support for supplementation in fed adults.
Every claim, traced back to its source
We took every major claim made about Niacin and matched it to the specific experimental model behind it. Click a claim to see the model, the finding, and our assessment of how much weight it deserves.
1 claims · evidence-by-evidence breakdown
1Open-LabelWeight: HighPellagra (severe niacin deficiency) causes alopecia, but this is irrelevant in fortified-food populationsReal for pellagra; irrelevant for any modern AGA patient eating a normal diet.
Historical clinical observation of pellagra cases and resolution with niacin repletion.
Pellagra patients show diffuse alopecia alongside the classic '3 D' symptoms (dermatitis, diarrhea, dementia). Repletion resolves all symptoms.
Real but historically narrow finding. Pellagra is essentially eliminated in populations with fortified bread/cereal. Modern AGA patients are not deficient in niacin, and supplementing them does nothing.
- Hegyi J, Schwartz RA, Hegyi V (2004). Int J Dermatol PMID 14693012
What's still missing from the science
- Any modern RCT — and we wouldn't expect one because the population that would benefit doesn't really exist.
Our verdict on Niacin
Not in our formulary yet
We don't carry this ingredient. We only formulate around actives where the evidence — and the safety profile — is strong enough to recommend with confidence. As the data matures, we may revisit.
Related treatments
How does Niacin stack up against its closest peers?
A genuine cause of reversible hair shedding in iron-deficient patients — but useless and potentially harmful if your iron stores are normal.
Read the breakdown →A botanical 5-alpha reductase inhibitor whose only high-quality trials (in BPH) showed no benefit over placebo; the positive AGA data are small and low-quality.
Read the breakdown →One small Malaysian RCT showed a hair-count increase. Never replicated. Used by Nutrafol to justify its tocotrienol content.
Read the breakdown →