Home/Skincare/YourProtocol/Vitamin B3 and Skin Cancer: What the '54%' Headline Actually Means
Skincare · YourProtocol
YourProtocol

Vitamin B3 and Skin Cancer: What the '54%' Headline Actually Means

The honest evidence on vitamin B3 and skin cancer: the 54% headline is real but badly misread, and the strongest randomized evidence is more mixed than the viral version suggests.

Mixed: one positive RCT in high-risk patients, one negative RCT in transplant recipients, no trial in people without a skin-cancer history
In-house · synthesized from the cited primary sources
At a glance
Time
5 min
Difficulty
Beginner
Limited The 54% figure comes from a subgroup of people who already had skin cancer, not a general-population risk cut.
What the evidence says

See what the study actually measured

A 2025 study of 33,822 US veterans found nicotinamide use linked to 14% fewer new skin cancers overall. The 54% figure applies only to the subgroup who started nicotinamide right after their first skin cancer; the benefit shrank with each additional prior cancer and was driven by squamous cell cancers only, with no reduction in basal cell. Everyone in the cohort already had skin cancer, so this is a recurrence rate, not a general risk cut.
Why ↓

The subgroup context is the single most important thing the viral headline leaves out.

Breglio et al., JAMA Dermatol 2025;161(11):1140-1147

See the trial evidence, including the line nobody quotes

In a phase 3 randomized trial of 386 people with at least two prior nonmelanoma skin cancers, nicotinamide 500 mg twice daily cut new nonmelanoma skin cancers 23% over 12 months. The trial's own conclusion, verbatim: 'There was no evidence of benefit after nicotinamide was discontinued.'
Why ↓

This is the strongest positive evidence that exists, and even it comes with a real limit: the benefit did not persist after stopping.

Chen et al. (ONTRAC), NEJM 2015

See where the evidence disagrees

A randomized trial in organ transplant recipients found 207 new skin cancers on nicotinamide vs 210 on placebo, a rate ratio of 1.0, no difference at all.
Why ↓

Two real randomized trials of the same molecule reached different conclusions in different populations; that disagreement is itself the honest finding.

Allen et al., NEJM 2023;388(9):804-812

Check which vitamin B3 you actually mean

Nicotinamide is not niacin, and neither is the same as nicotinamide riboside or NMN. Every skin-cancer trial used nicotinamide specifically. Nicotinamide does not cause the flushing niacin does.
Why ↓

Reading a niacin label as if it were the studied molecule is one of the most common mistakes in this story.

NIH Office of Dietary Supplements, Niacin Fact Sheet, updated Nov 2022

See what has never been tested

No randomized trial has ever tested nicotinamide for skin cancer prevention in people with no prior skin cancer.
Why ↓

This is the boundary of what the evidence can actually tell someone with no cancer history.

Chen et al. 2015; Allen et al. 2023

See the intervention with real population-level evidence

A randomized trial of 1,621 adults found daily sunscreen cut new squamous cell tumors by about 39% over 4.5 years, in a general population, not just people with prior skin cancer.
Why ↓

This is the strongest single intervention for skin cancer prevention with randomized evidence in ordinary people.

Green et al. (Nambour trial), Lancet 1999
The evidence 5
Limited

The 54% figure comes from a subgroup of people who already had skin cancer, not a general-population risk cut.

Niacin Fact Sheet for Health Professionals (NIH Office of Dietary Supplements) Read ods.od.nih.gov
Nicotinamide for Skin Cancer Chemoprevention (Breglio et al., JAMA Dermatology, 2025) Read pubmed.ncbi.nlm.nih.gov
A Phase 3 Randomized Trial of Nicotinamide for Skin-Cancer Chemoprevention (Chen et al., NEJM, 2015) Read pubmed.ncbi.nlm.nih.gov
Nicotinamide for Skin-Cancer Chemoprevention in Transplant Recipients (Allen et al., NEJM, 2023) Read pubmed.ncbi.nlm.nih.gov
Daily Sunscreen Use and Squamous Cell Carcinoma (Green et al., Nambour Trial, Lancet, 1999) Read pubmed.ncbi.nlm.nih.gov
Related protocols
Skincare Moderate

Evidence-Based Acne Routine

Michelle WongDaily, AM & PM

Not medical advice. This page is for education only and is not a substitute for professional medical care. Consult a qualified clinician before changing your health routine.
Editorial disclosure. This protocol is written and fact-checked by the YourProtocol editorial team directly from the primary sources cited below; it is not written or reviewed by any outside expert.

Is this for you
  • Anyone who saw the '54% lower skin cancer risk' claim and wants the real context
  • Anyone with a personal or family history of skin cancer weighing whether to ask a doctor about nicotinamide
  • Anyone confused about the difference between niacin, nicotinamide, NR and NMN
Cautions
  • This page reports population-level cancer-risk research; it is not a personal risk assessment, and every number here describes a study population, not any individual
  • No dosing is given as advice; the ONTRAC trial dose (1,000 mg/day total) is reported only as trial context, far above the 35 mg/day tolerable upper intake level for supplemental niacin
  • Anyone with a personal history of skin cancer should route this question to a dermatologist or oncologist, not decide from this page alone
  • Educational only, not medical advice
Common questions
Does vitamin B3 prevent skin cancer?
The evidence is mixed and population-specific. In a randomized trial (ONTRAC, NEJM 2015) of people with a history of at least two skin cancers, nicotinamide 500mg twice daily cut new nonmelanoma skin cancers 23% over 12 months, but the benefit disappeared once people stopped taking it. A larger randomized trial in organ transplant recipients (NEJM 2023) found no benefit at all. No trial has tested it for prevention in people with no prior skin cancer.
Is nicotinamide the same as niacin?
No. Both are forms of vitamin B3, but they behave differently: nicotinamide does not cause the flushing niacin does, and every skin-cancer trial used nicotinamide specifically, not niacin. Check the label on any B3 supplement to see which one you actually have.
Where does the '54% lower risk' statistic come from?
A 2025 retrospective study of US veterans (JAMA Dermatology) found a 14% overall reduction in new skin cancers among nicotinamide users, and a 54% reduction in the specific subgroup who started it right after their first skin cancer. Everyone in that study already had skin cancer, so this is a recurrence rate in a high-risk group, not a general prevention number.
Does the benefit last after you stop taking it?
No. The ONTRAC trial's own conclusion states there was no evidence of benefit after nicotinamide was discontinued.
What has the strongest evidence for skin cancer prevention in the general population?
Daily sunscreen. A randomized trial found it cut new squamous cell skin cancers by about 39% over 4.5 years in an ordinary adult population, not just people with prior skin cancer.
Get the next protocol first
Evidence updates, cited to the source. No spam.