Niacinamide (nicotinamide): Evidence, Trial Doses & Interactions

About Niacinamide (nicotinamide)

The amide form of vitamin B3. It satisfies the same vitamin requirement as nicotinic acid but does not activate the receptor responsible for flushing, and it has no meaningful effect on blood lipids.

Niacinamide is the quieter half of vitamin B3 and, unusually, has a genuine randomised result behind it in a specific population: in people with a history of multiple non-melanoma skin cancers, 500 mg twice daily reduced new lesions by around a quarter over twelve months in the ONTRAC trial. A later trial in organ transplant recipients — a much higher-risk group — was null, which is a real limit on how far the finding generalises. Its other well-known use is topical, in skincare, where the evidence is separate from anything swallowed. As a general supplement on an adequate diet, it has nothing demonstrated to offer.

Sold as

Tablet, Capsule, Topical serum (separate evidence base), Component of B-complex and multivitamins

Also known as

Nicotinamide, Vitamin B3 (amide form), Non-flushing niacin

Regulation: Covered by the same 35 mg/day Tolerable Upper Intake Level as niacin, set on the flushing endpoint for nicotinic acid — a ceiling that the studied skin-cancer dose of 1,000 mg/day exceeds by nearly thirtyfold. Sold as a dietary supplement with no pre-market efficacy review.

What the research used

The amounts, forms and durations published trials of Niacinamide (nicotinamide) actually administered.

These are the amounts published trials administered — not a recommendation, and not a dose to copy. Trial participants were screened, supervised and given a characterised preparation. What is in a retail bottle is frequently not what was studied, and the amount that suits one person is not general advice.

Studied for Non-melanoma skin cancer recurrence trial
1000 mg
Moderate
500 mg twice daily · 12 months
From the ONTRAC trial in people with at least two prior keratinocyte cancers. Benefit did not persist after stopping, and a subsequent trial in organ transplant recipients found no effect.
Studied for Tolerable Upper Intake Level, adults
35 mg
Strong
The vitamin B3 upper limit applies to niacinamide as well as nicotinic acid, though the flushing basis for it does not — which is one reason therapeutic trials have used far higher doses under supervision.
Studied for Typical retail supplement
250–500 mg
Not enough
Tablet or capsule
Well above the RDA and well above the upper limit, with no evidence of benefit at these doses outside the specific dermatological population studied.

This is general information about food, not medical advice. It cannot diagnose, treat or replace guidance from a clinician who knows your history.

When it was taken

Each window says whether a trial compared it against an alternative, or whether it is convention and pharmacology. Most timing advice is the second kind.

None of the timings below were directly compared in a trial. They reflect how the research happened to dose, or what the pharmacology implies — which is not the same as a timing being better.

With food
Not enough
Taken with food in the skin-cancer trials and generally better tolerated that way. No trial has compared timings.
Timing was not directly compared. This reflects convention or how the compound behaves in the body, not a trial showing this window works better.

What each association actually rests on, and the papers behind it. A rating describes the state of the research, not how promising the supplement sounds. How we rate evidence.

Skin photoprotection

Skin Health

Moderate evidence

One well-conducted randomised trial in people with a history of multiple keratinocyte skin cancers found around a quarter fewer new lesions over a year at 500 mg twice daily. The effect disappeared after stopping, and a later trial in transplant recipients was null, so the finding is real but narrow.

What may be going on: Nicotinamide is a precursor of NAD, and replenishing cellular NAD after ultraviolet exposure supports DNA repair and reduces UV-induced immune suppression in laboratory work.

Moderate evidence. Several human studies point the same way, with real caveats.

View the 4 sources

The effect of niacinamide on reducing cutaneous pigmentation and suppression of melanosome transfer.(opens in a new tab)
Randomised controlled trial · The British journal of dermatology · 2002 · PMID 12100180
A Phase 3 Randomized Trial of Nicotinamide for Skin-Cancer Chemoprevention.(opens in a new tab)
Randomised controlled trial · The New England journal of medicine · 2015 · PMID 26488693
Effect of Nicotinamide in Skin Cancer and Actinic Keratoses Chemoprophylaxis, and Adverse Effects Related to Nicotinamide: A Systematic Review and Meta-Analysis.(opens in a new tab)
Meta-analysis · Journal of cutaneous medicine and surgery · 2022 · PMID 35134311
Nicotinamide for Skin-Cancer Chemoprevention in Transplant Recipients.(opens in a new tab)
Randomised controlled trial · The New England journal of medicine · 2023 · PMID 36856616

Deep research mode adds each paper’s own conclusion and stated limitations.

Skin structure and hydration

Skin Health

Limited evidence

Topical niacinamide has reasonable evidence for skin barrier and pigmentation measures in short cosmetic trials. That evidence belongs to the cream, not to a tablet, and the two are frequently conflated in marketing.

Limited evidence. Early human work, or mostly lab and animal research.

View the 3 sources

Niacinamide: A B vitamin that improves aging facial skin appearance.(opens in a new tab)
Randomised controlled trial · Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.] · 2005 · PMID 16029679
The effect of 2% niacinamide on facial sebum production.(opens in a new tab)
Randomised controlled trial · Journal of cosmetic and laser therapy : official publication of the European Society for Laser Dermatology · 2006 · PMID 16766489
Efficacy of ceramides and niacinamide-containing moisturizer versus hydrophilic cream in combination with topical anti-acne treatment in mild to moderate acne vulgaris: A split face, double-blinded, randomized controlled trial.(opens in a new tab)
Randomised controlled trial · Journal of cosmetic dermatology · 2024 · PMID 38299457

Deep research mode adds each paper’s own conclusion and stated limitations.

Joint comfort

Joint Health

Not enough evidence

There is not enough evidence that niacinamide improves osteoarthritis symptoms. The idea rests on one small trial from the 1990s that has not been replicated.

Not enough evidence. Not enough human research to say anything useful yet.

View the 1 source

The effect of niacinamide on osteoarthritis: a pilot study.(opens in a new tab)
Randomised controlled trial · Inflammation research : official journal of the European Histamine Research Society ... [et al.] · 1996 · PMID 8841834

Deep research mode adds each paper’s own conclusion and stated limitations.

Things to know

Interactions, contraindications and dose limits, most serious first. Concentrated extracts interact with medication in ways the whole plant does not, so this section carries more weight here than it does on a food page.

Too much
Liver injury at high doses
Hepatotoxicity has been reported with gram-level nicotinamide, and doses above 3 g/day are associated with raised liver enzymes. The doses used in dermatology trials sit well above the vitamin B3 upper limit and were given under medical supervision with monitoring.
Worth knowing
No lipid effect — not interchangeable with niacin
Niacinamide does not lower LDL or raise HDL, because it does not act on the receptor pathway that nicotinic acid does. Products marketed as "no-flush niacin" for cholesterol are trading on a similarity that does not exist pharmacologically.
Too much
May worsen insulin sensitivity at high doses
Gram-level nicotinamide has been reported to reduce insulin sensitivity in some studies, which matters for people with or at risk of diabetes and mirrors the glycaemic effects seen with high-dose nicotinic acid.
Interaction
Interaction with carbamazepine and anticonvulsants
Interacts withCarbamazepine, primidone
High-dose nicotinamide has been reported to raise blood levels of carbamazepine and primidone, so people on anticonvulsants should not take gram doses without medical input.

Niacinamide (nicotinamide)

What niacinamide (nicotinamide) may help with

About Niacinamide (nicotinamide)

What the research used

When it was taken

With food

The evidence in depth

Skin photoprotection

Skin structure and hydration

Joint comfort

Things to know

Liver injury at high doses

No lipid effect — not interchangeable with niacin

May worsen insulin sensitivity at high doses

Interaction with carbamazepine and anticonvulsants

What niacinamide (nicotinamide) may help with

About Niacinamide (nicotinamide)

What the research used

When it was taken

🍽️With food

The evidence in depth

Skin photoprotection

Skin structure and hydration

Joint comfort

Things to know

Liver injury at high doses

No lipid effect — not interchangeable with niacin

May worsen insulin sensitivity at high doses

Interaction with carbamazepine and anticonvulsants

With food