Niacinamide (nicotinamide)
Summary
Niacinamide is a form of vitamin B3. In a 386-person trial of people with past skin cancers, 500 mg twice daily for a year cut new non-melanoma skin cancers by 23% (grade B); a 158-person transplant trial found no effect. Supplement doses far exceed the 35 mg upper limit set for healthy people.
Key facts
- The amide form of vitamin B3; it does not cause flushing and does not lower cholesterol the way nicotinic acid does[4]
- 1 g a day for 12 months lowered new non-melanoma skin cancers by 23% and actinic keratoses by 11–20% in 386 people with at least two past skin cancers; no benefit remained after stopping[1]
- The same dose had no effect on skin cancers in 158 organ-transplant recipients[2]
- The adult UL for supplemental niacin, 35 mg a day, applies to nicotinamide too; trial doses (1–3 g) were used under medical follow-up[4][1]
- 3 graded human outcomes on this page
- October 11, 2026
How it works
ProposedNicotinamide is a precursor of NAD+; it enhances repair of UV-induced DNA damage and reduces UV-related immune suppression in the skin.[2]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Hair & skin | Grade B | Improved | RCT · n = 386 · 2015 | 2 rows |
| Healthy aging | Grade D | Improved | Crossover RCT · n = 57 · 2020 | 1 row |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| New non-melanoma skin cancers | Improved | Grade B | RCT · n = 386 · 2015 Adults with at least two non-melanoma skin cancers in the past 5 years Form: Nicotinamide · Dose: 1 g/day (500 mg twice daily) · Duration: 12 months New non-melanoma skin cancers were 23% lower than with placebo; actinic keratoses were 11–20% lower; adverse events were similar. | 26488693 (opens PubMed)Source [1] |
| New keratinocyte cancers in transplant recipients | No effect | Grade D | RCT · n = 158 · 2023 Organ-transplant recipients with at least two prior keratinocyte cancers Form: Nicotinamide · Dose: 1 g/day (500 mg twice daily) · Duration: 12 months 207 new cancers with nicotinamide versus 210 with placebo; no difference in actinic keratoses or quality of life. | 36856616 (opens PubMed)Source [2] |
| Inner retinal function in glaucoma | Improved | Grade D | Crossover RCT · n = 57 · 2020 Adults treated for glaucoma Form: Nicotinamide · Dose: 1.5 g/day then 3 g/day · Duration: 12 weeks per arm A retinal electrical response improved 14.8% on nicotinamide versus 5.2% on placebo; more people gained visual field. | 32721104 (opens PubMed)Source [3] |
Forms
Studied doses
Doses studied in human trials ranged from 1 g of nicotinamide a day for 12 months to 3 g a day for 6 weeks.[1][3]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- Anyone using it without medical follow-up
- Common supplement doses (450 mg or more) are many times the 35 mg upper limit; the trials used it with regular check-ups.[4][1]
- Pregnancy and breastfeeding
- The 35 mg upper limit also applies in pregnancy and breastfeeding.[4]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Where to buy Niacinamide (nicotinamide)
Products from brands we partner with that contain Niacinamide (nicotinamide). Listing a product is not a claim that it works; check the amount per serving against the doses studied above, and the label for other ingredients.
- SupersmartPaid linkNiacinamide1 capsule: 450 mg niacinamide; 180 servings. Below the 1 g a day used in the skin cancer trial but about 13 times the 35 mg upper limit for healthy adults.Shop at Supersmart (opens in new tab)Price and label checked 2026-10-11 on the brand’s site.
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Frequently asked questions
Is niacinamide the same as niacin?
Both are vitamin B3, but niacinamide (nicotinamide) does not cause flushing or change cholesterol the way nicotinic acid does.[4]
Does niacinamide lower skin cancer risk?
In 386 people with past non-melanoma skin cancers, 1 g a day lowered new cases by 23% while it was taken. It had no effect in transplant recipients and is not a substitute for dermatology follow-up.[1][2]
Sources
- [1]A Phase 3 Randomized Trial of Nicotinamide for Skin-Cancer Chemoprevention.. N Engl J Med, 2015. RCT
- [2]Nicotinamide for Skin-Cancer Chemoprevention in Transplant Recipients.. N Engl J Med, 2023. RCT
- [3]Improvement in inner retinal function in glaucoma with nicotinamide (vitamin B3) supplementation: A crossover randomized clinical trial.. Clin Exp Ophthalmol, 2020. crossover-RCT
- [4]Niacin: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements, 2022. fact-sheet
What changed
- Effect arrows corrected on 1 row(s): outcomes where a harmful measure fell (pain, symptoms, blood pressure, lipids, glucose, risk) now show as improved (up). No study data changed.
- First draft. Every PMID checked against NCBI E-utilities (title, year and journal taken from the PubMed record) and abstracts read for each cited row. Product details in Where to buy read from the brand page on the date shown. Self-reviewed in a second strict pass (no independent reviewer yet).