Water-soluble vitamin B3 (amide form)
Brand names: Niacinamide
Updated · Methodology
First line
Nicotinamide is the treatment of choice for pellagra because it does not cause flushing and is well tolerated at high doses. recommends 100–300 mg/day orally in 3–4 divided doses for 3–4 weeks. Dermatitis and diarrhoea regress in the first days; neurological symptoms in 1–2 weeks. Other B vitamins are replenished and adequate protein intake is ensured in parallel.
Sources
ICD-10: E52 · ICD-11: 5B5C.0
Adjunct
Nicotinamide 500 mg twice daily for 12 months reduced non-melanoma skin cancer (basal and squamous cell) by 23% in patients with a history of more than 2 NMSC in 5 years (ONTRAC trial, NEJM 2015). AEDV 2022 includes nicotinamide as an option for secondary NMSC prevention in high-risk patients (history of multiple NMSC, post-transplant immunosuppression). In patients without prior skin cancer there is no evidence base for prophylactic use. Discuss with a dermatologist if you have a post-transplant immunosuppression diagnosis and multiple actinic keratoses; everyone else does not need it.
The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.
Not recommended
Nicotinamide is a NAD+ precursor, and the age-related decline of NAD+ has become the marketing basis for «longevity». Supplement makers sell nicotinamide, NMN and nicotinamide riboside as «anti-aging molecules». No large human RCT has shown extended lifespan or slowed aging. Short-term human studies (8–12 weeks, n<100) show elevated blood NAD+, but translation to clinically meaningful endpoints – reduced sarcopenia, improved cognition, fewer cardiovascular events – is absent. At high doses (>3 g/day) hepatotoxicity has been described. If the product was suggested «for longevity», consider seeking a second opinion.
Nicotinamide is the amide form of vitamin B3. The body uses it as a precursor of NAD+ and NADP+, key coenzymes for redox reactions, PARP-mediated DNA repair and sirtuin-driven epigenetic regulation. Unlike nicotinic acid, nicotinamide does not activate GPR109A and does not cause flushing, so high-dose tolerability is better. No meaningful lipid-modifying effect.
Daily intake in pregnancy 18 mg. Therapeutic doses for pellagra (100–300 mg/day) are considered safe by AEMPS. High doses for «anti-aging» purposes are not studied and not recommended.
Compatible at physiological and therapeutic doses (Hale L1). High «anti-aging» doses during lactation are not studied; better avoided.
Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.
Verbatim lines from the interaction sections, in the language of the label
«Fármacos que pueden aumentar los niveles plasmáticos de la carbamazepina: Otros: zumo de pomelo, nicotinamida (sólo a dosis altas).»AEMPS, section 4.5 · Open on CIMA
«Drug Interactions: Metronidazole may interfere with certain types of determinations of serum chemistry values, such as aspartate aminotransferase (AST, SGOT), alanine aminotransferase (ALT, SGPT)…»FDA, section 7 · Open on DailyMed
«Laboratory Test Interactions: Tinidazole, like metronidazole, may interfere with certain types of determinations of serum chemistry values, such as aspartate aminotransferase (AST, SGOT), alanine…»FDA, section 7 · Open on DailyMed
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Nicotinamide is evaluated for the following indications with varying evidence strength: Pellagra (vitamin B3 deficiency) (evidence tier A), Skin, hair and nail beauty (evidence tier B), Anti-aging and longevity (evidence tier F). See the full indication matrix with dosing and citations above on this page.
Common side effects of Nicotinamide (≥ 1 in 100): Nausea, Headache, Dizziness, Rash. See the Safety section for uncommon and serious reactions.
Daily intake in pregnancy 18 mg. Therapeutic doses for pellagra (100–300 mg/day) are considered safe by AEMPS. High doses for «anti-aging» purposes are not studied and not recommended.
Compatible at physiological and therapeutic doses (Hale L1). High «anti-aging» doses during lactation are not studied; better avoided.
Nicotinamide is contraindicated in: Hypersensitivity to nicotinamide; Severe hepatic impairment. Full list in the Safety section.
Direct links to regulator labels. Open in a new tab.
Nicotinamide riboside (NR), Black seed (Nigella sativa), Nicotinamide mononucleotide (NMN), Olive leaf extract (Olea europaea, oleuropein), Quercetin, Tribulus terrestris (puncture vine), Beta-carotene, Epigallocatechin-3-gallate (EGCG, main green tea polyphenol)