Oral nicotinamide (vitamin B3)

In a large trial in people who already had several skin cancers, those taking nicotinamide developed about 23% fewer new non-melanoma skin cancers than those on placebo. It is something worth discussing with a clinician if you are at higher risk, as an extra layer next to sunscreen, sun protection, and skin checks, not a replacement for any of them.

• Nicotinamide (also called niacinamide), not niacin or nicotinic acid
• A product from a brand that tests for quality and purity
• The exact amount per capsule printed on the label
• Plain capsules without added herbs or extras

• Niacin or nicotinic acid, which causes flushing and is a different product
• Starting it on your own without talking to your clinician
• Counting on it instead of sunscreen and skin checks

The benefit was seen only while people kept taking it and faded after stopping, and it has not been shown to help people with organ transplants, so check with your clinician before starting.

If you have had more than one skin cancer or are at higher risk for them, ask your clinician whether oral nicotinamide makes sense for you and how much to take.

• Practical Dermatology: Nicotinamide for skin cancer chemoprevention (ONTRAC and later data)
• DermNet: Nicotinamide