Vitamin B3 (nicotinamide)

Who is this information for?

At Spot Check Clinic, Dr Chris recommends oral nicotinamide only for patients who have previously had a basal cell carcinoma (BCC) or squamous cell carcinoma (SCC). It is not routinely recommended for people without that history.

What does the evidence show?

Oral nicotinamide, a form of vitamin B3, may reduce the number of new nonmelanoma skin cancers and solar keratoses in people who have previously had skin cancers. Your doctor can advise whether it is appropriate for you. It does not replace sun protection or skin checks.

In a randomised trial of 386 people with at least two previous nonmelanoma skin cancers, 500 mg twice daily reduced the combined rate of new BCCs and SCCs by 23% over one year. The BCC-only result was not statistically conclusive. Solar keratoses were also reduced. Benefit was not maintained after treatment stopped.

A large observational study published in 2025 found fewer new skin cancers among people taking nicotinamide, particularly SCCs. The association was stronger when use began sooner after a first skin cancer. This is an observational finding and does not establish that starting early caused the difference or predict an individual benefit.

A separate trial in organ-transplant recipients did not show a reduction in skin cancers. People who have had a transplant should discuss this with their treating doctor. Nicotinamide is not an established treatment for preventing melanoma.

Taking nicotinamide

When Dr Chris recommends it, the dose is 500 mg twice daily. Follow the plan discussed during your consultation, including when to review ongoing use.

Check that the product contains nicotinamide, also called niacinamide. Nicotinic acid is a different form of vitamin B3 and is not an interchangeable substitute. A pharmacist can help you check the label.

Sun protection and follow-up

Nicotinamide does not prevent all skin cancers or protect against sunburn. Continue sunscreen, protective clothing and your recommended skin checks. Have new or changing spots assessed rather than relying on supplements.