Skin Cancer
Abnormal growth of skin cells, most commonly caused by UV exposure.
TL;DR
Nicotinamide has genuine randomised evidence for reducing new skin cancers in high-risk people. Beta-carotene does not, and sun protection outperforms everything.
Overview
Skin cancer splits into keratinocyte cancers — basal cell and squamous cell carcinoma, which are common and rarely fatal — and melanoma, which is less common and far more dangerous. Cumulative ultraviolet exposure drives keratinocyte cancers; intermittent intense exposure and sunburn drive melanoma. This is the one cancer where a supplement has credible randomised support: the ONTRAC trial found nicotinamide at 500mg twice daily reduced new non-melanoma skin cancers by 23% over twelve months in people with a history of at least two in the previous five years. The effect is confined to high-risk individuals and disappears after stopping. Beta-carotene, by contrast, failed in prevention trials and increased lung cancer risk in smokers. Nothing replaces sun protection and skin surveillance, and vitamin D can be maintained by supplementation rather than by deliberate UV exposure.
Common Symptoms
- •A new or changing mole
- •A sore that does not heal within four weeks
- •A pearly or waxy bump
- •A scaly red patch that bleeds or crusts
- •Asymmetry, irregular border, colour variation or diameter over 6mm in a mole
- •A mole that itches or bleeds
Common Causes
- •Cumulative and intermittent UV exposure
- •Sunburn history, particularly in childhood
- •Fair skin, red or blond hair, freckling
- •Sunbed use
- •Immunosuppression, especially after organ transplant
- •Large numbers of moles or atypical naevi
- •Family history of melanoma
Root Causes
Ultraviolet-induced DNA damage producing characteristic mutations, combined with impaired DNA repair capacity, immunosuppression, and inherited pigmentation traits that determine UV susceptibility.
How It's Diagnosed
Diagnostic Markers
- Full skin examination with dermoscopy
- Excisional biopsy with Breslow thickness for melanoma
- Sentinel lymph node biopsy in intermediate-thickness melanoma
- Photographic mole mapping in high-risk patients
When to See a Doctor
See a doctor promptly for any mole that changes in size, shape or colour, a lesion that bleeds or fails to heal within four weeks, or a new pigmented lesion appearing in adulthood.
Supplements Studied For This
Diet & Lifestyle
Suggested Pattern
No dietary pattern prevents skin cancer. Nutrition matters only for maintaining vitamin D without UV exposure.
Eat more
- Oily fish and fortified foods for vitamin D
- Colourful vegetables and fruit as part of general health
- Adequate protein for wound healing after excisions
Avoid
- Beta-carotene supplements, particularly in smokers
- Deliberate sun exposure for vitamin D
- Sunbeds in any form
Supporting Research
A phase 3 randomized trial of nicotinamide for skin-cancer chemoprevention
Selenium supplementation, baseline plasma selenium status and incidence of prostate cancer: an analysis of the complete treatment period of the Nutritional Prevention of Cancer Trial
Oral Nicotinamide for Actinic Keratosis Prevention in Kidney Transplant Recipients: A Pilot Double-Blind, Randomized, Placebo-Controlled Trial
Drugs for preventing lung cancer in healthy people
Role of VDR gene polymorphisms and environmental factors in the development of skin cancers: evidence by updated meta-analysis
Frequently Asked Questions
Is nicotinamide the same as niacin?
Should everyone take it?
Do I need sun for vitamin D?
Who It Affects
The most commonly diagnosed cancer group in fair-skinned populations; keratinocyte cancers vastly outnumber melanoma.
Highest incidence in fair-skinned people with high UV exposure; organ transplant recipients carry many times the baseline risk.
Quick Facts
- •Nicotinamide reduced new keratinocyte cancers by 23% in the ONTRAC trial
- •Nicotinamide is not niacin — niacin causes flushing and lacks this evidence
- •Beta-carotene increased lung cancer risk in smokers and does not prevent skin cancer
- •The ABCDE rule and the ugly duckling sign both help identify melanoma
Lifestyle Tips
- •Use SPF 30+ broad spectrum daily on exposed skin, reapplied every two hours outdoors
- •Seek shade between 11am and 3pm and wear a hat and long sleeves
- •Never use sunbeds
- •Check your skin monthly and photograph any changing lesion
- •Consider nicotinamide 500mg twice daily if you have had two or more keratinocyte cancers — discuss with your dermatologist
- •Maintain vitamin D by supplement rather than by sun exposure
My Notes
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This information is for educational purposes only. Always consult a healthcare professional before starting any supplement regimen.