Huge VA Study: Vitamin B3 Cut Repeat Skin Cancers by Up to 54%
A cheap over-the-counter B3 supplement showing this much benefit reframes skin cancer prevention beyond sunscreen alone — especially for people who've already had one.
A JAMA Dermatology study published 17 September 2025, of 33,833 Veterans Affairs patients, found oral nicotinamide (500 mg twice daily) was associated with a 14% overall reduction in keratinocyte skin cancers, rising to a 54% reduction when started after a person's first skin cancer.
Researchers describe nicotinamide as an inexpensive, accessible add-on for higher-risk patients, while cautioning that it supplements — rather than replaces — sun protection and routine skin checks, and that people should discuss supplementation with a clinician.
Questions we get a lot
How much did nicotinamide reduce skin cancer in the VA study?
In the September 2025 JAMA Dermatology study of 33,833 VA patients, oral nicotinamide at 500 mg twice daily was linked to a 14% overall reduction in keratinocyte skin cancers. The effect was much larger — about 54% — among people who started taking it after their first skin cancer diagnosis.
Should I start taking vitamin B3 to prevent skin cancer?
Nicotinamide (a form of vitamin B3) showed the most benefit in people who had already had a skin cancer, not the general population. It is not a substitute for sunscreen, protective clothing, and regular skin checks. Talk to a dermatologist before starting supplementation, especially if you have a history of skin cancer.
r/SkincareAddiction: 'My dad just had a skin cancer removed — is the vitamin B3 from this new study something he should ask his dermatologist about?'