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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
Nicotinamide doesn't have enough studies with structured effect-size data yet to pool a verdict. Browse the studies below for individual findings.
Most evidence is from high-quality meta-analyses and randomised trials published 1980–2026 with a typical study size of 310 participants.
Based on 108 studies · 4 meta-analyses · 86 RCTs · 336 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.
87 randomised trials
every one checked individually
Every randomised or controlled trial of Nicotinamide indexed in PubMed, not a hand-picked subset. Meta-analyses and systematic reviews are deliberately excluded from this count: most of them cover many compounds at once, so counting them would inflate it.
PubMed · as of Jul 2026
187 trials ongoing or recruiting · 896 completed on ClinicalTrials.gov
277 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momentum for Nicotinamide, not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed.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 Nov 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 one 76-person RCT found no significant difference between 4% nicotinamide gel and 1% clindamycin gel.
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 use backed by a phase 3 trial (skin-cancer chemoprevention in high-risk patients) 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: If you develop a new or unexpected symptom, pause this optional product and seek advice before trying a lower dose, a different schedule or an added remedy. Follow any urgent instructions for the symptom now.
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 108 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. Individual needs vary, so check the right dose for you with a healthcare provider.
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 include elevated liver enzymes (high doses), thrombocytopenia (high-dose, dialysis use), nausea / GI upset. How often they occur is not established for all of them. 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
Likely helpsHumans cannot synthesize this vitamin — required for collagen production, immune cell function, and iron absorption; athletes need more.
Vitamin B12
Likely helpsDrives nerve myelination, red blood cell formation, and DNA synthesis — deficiency is common in vegans, vegetarians, and older adults.
Vitamin D3
Probably helpsHormone-like vitamin that regulates 1,000+ genes — deficiency is widespread and linked to poor immunity, depression, and bone loss.
Vitamin A
Limited supportFat-soluble vitamin that maintains night vision, drives immune cell differentiation, and regulates skin turnover and cellular growth.
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Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 108 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.
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