We use essential cookies (authentication, your saved goals/stack) by default. With your permission we’ll also enable privacy-respecting analytics (Vercel Web Analytics, anonymous load-time metrics) and error-replay diagnostics (Sentry — DOM snapshots only when an error fires) so we can fix bugs faster. Learn more about cookies
Nicotinamide (Niacinamide, Vitamin B3)
The amide form of vitamin B3 and a NAD+ precursor. Unlike the NAD+-longevity story, its strongest evidence is dermatologic: a Phase-3 RCT showed it cuts new non-melanoma skin cancers and actinic keratoses in high-risk patients, and it has long been used for acne. The NAD+/anti-aging rationale is real but unproven in humans.
What the evidence says
Most Nicotinamide studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from high-quality meta-analyses and randomised trials published 1980–2026 with a typical study size of 43 participants.
Based on 106 studies · 4 meta-analyses · 86 RCTs · 8,363 total participants
Confidence
High confidenceWhat the studies found
By outcome
A Phase-3 RCT (ONTRAC) gives nicotinamide genuinely strong evidence for one outcome — reducing new non-melanoma skin cancers and actinic keratoses in high-risk patients — plus older dermatology RCTs for acne. But the broader NAD+/anti-aging rationale is mechanistic and unproven in humans, the renal/phosphate trials are mixed and tolerability-limited, and cognition was null even within ONTRAC, holding the overall score to Moderate.
94 rigorous studies
87 randomized trials · 4 meta-analyses · 3 systematic reviews
Our evidence rating for Nicotinamide is accountable to this entire body of rigorous research indexed in PubMed — not a hand-picked subset.
PubMed · as of Jul 2026
181 trials ongoing or recruiting · 886 completed on ClinicalTrials.gov
275 of the completed trials have posted results
Registered trials show research momentum for Nicotinamide, not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed. They are never counted toward the evidence rating above.
Browse these trials on ClinicalTrials.govClinicalTrials.gov · as of Sep 2026
Nicotinamide (niacinamide) is the amide form of vitamin B3 and a direct precursor to NAD+, the coenzyme central to cellular energy metabolism and DNA repair. Unlike niacin (nicotinic acid), it does not cause flushing and has a far weaker effect on lipids.
Its best human evidence is in dermatology rather than longevity: the Phase-3 ONTRAC randomized trial showed that 500 mg twice daily reduced the rate of new non-melanoma skin cancers by 23% and actinic keratoses by ~13-20% in high-risk patients with prior skin cancers — a genuinely landmark chemoprevention result.
Topical and oral niacinamide also have a long history in acne, where a classic RCT found 4% nicotinamide gel comparable to clindamycin.
The NAD+-precursor angle is mechanistically plausible — nicotinamide replenishes NAD+, the substrate for PARP-driven DNA repair and sirtuin signaling, both relevant to UV-damaged skin and aging — but, as with NMN and NR, a human longevity or healthspan benefit from raising NAD+ remains unproven.
It is well tolerated at normal doses; high doses can cause GI upset and, rarely, hepatotoxicity (less than niacin), and renal/dialysis phosphate-binding trials have been mixed and tolerability-limited.
An honest, useful, inexpensive supplement with one strong proven use (skin-cancer chemoprevention) and a speculative longevity rationale.
Enters the NAD+ salvage pathway, replenishing the NAD+ pool that fuels cellular energy and repair
Provides NAD+ as substrate for PARP enzymes that repair UV-induced DNA damage in skin
Prevents UV-induced ATP depletion and immunosuppression, the basis of its skin-cancer chemoprevention
How Nicotinamide works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Vitamin B3 is required in pregnancy at RDA levels; high supplemental doses are not established — stay within normal intake unless directed
Used investigationally as a phosphate binder but tolerability is poor at high doses (NICOREN); use only under nephrology supervision
Avoid gram-level chronic dosing; monitor liver enzymes
High-dose nicotinamide may inhibit hepatic metabolism of some drugs; monitor with anticonvulsants at gram-level doses
Tip: Take with food; lower the dose
Tip: Avoid gram-level chronic dosing without monitoring; far less hepatotoxic than niacin
Tip: Seen in the NICOREN dialysis trial at gram-level doses; monitor platelets in renal use
Nicotinamide has an evidence score of 5.5/10 — moderate evidence based on 35 indexed studies. The amide form of vitamin B3 and a NAD+ precursor. Unlike the NAD+-longevity story, its strongest evidence is dermatologic: a Phase-3 RCT showed it cuts new non-melanoma skin cancers and actinic keratoses in high-risk patients, and it has long been used for acne. The NAD+/anti-aging rationale is real but unproven in humans. Representative study: PMID 26488693.
The commonly studied dose of Nicotinamide is 500mg twice daily. Research points to an estimated optimal dose around 1000mg, with a minimum effective dose near 500mg. Individual response varies — start low and adjust.
The best time to take Nicotinamide is with meals. Taking it with food is preferred. Nicotinamide is water-soluble and well absorbed orally; taking it with food reduces the mild GI upset that can occur at higher doses.
Nicotinamide is generally well-tolerated and considered safe for most healthy adults at recommended doses. Reported side effects are uncommon and include nausea / GI upset, elevated liver enzymes (high doses), thrombocytopenia (high-dose, dialysis use). Use caution if any of these apply to you: Known hypersensitivity to niacin/niacinamide; Severe hepatic impairment (caution at high doses).
Smoking status: not checked. Vitamin A: what these mean for you changes depending on whether you smoke or used to, and you have not told us. That check was skipped.
Vitamin C
Probably helpsHumans cannot synthesize this vitamin — required for collagen production, immune cell function, and iron absorption; athletes need more.
Vitamin A
Mixed evidenceFat-soluble vitamin that maintains night vision, drives immune cell differentiation, and regulates skin turnover and cellular growth.
Choline
Probably helpsPrecursor to acetylcholine and phosphatidylcholine — critical for memory, liver function, and cell membrane integrity.
Niacin
Probably helpsNAD+ precursor that raises HDL, lowers LDL and triglycerides, and fuels cellular energy metabolism at therapeutic doses.
Explore: Best supplements for Body HealthBest supplements for Vitality & LongevityBest supplements for Focus, Memory & Mood
Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 106 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Tap node to isolate • Pinch to zoom • Tap edge for research