Nicotinamide (Vitamin B3 Oral)

Oral nicotinamide (the amide form of vitamin B3, also called niacinamide when referring to both oral and topical use) boosts cellular NAD+ levels. NAD+ is a critical coenzyme for ATP production and is required for PARP-mediated DNA repair following UV damage. UV radiation depletes cellular NAD+, impairing the cell’s ability to repair DNA damage — this is a key mechanism in skin cancer development.

By replenishing NAD+ levels, oral nicotinamide enhances the skin’s capacity to repair UV-induced DNA damage, reduces immunosuppression caused by UV exposure, and supports cellular energy metabolism. These mechanisms are distinct from topical niacinamide’s primary effects (barrier support, oil control, pigmentation).

• Reduced incidence of non-melanoma skin cancers by ~23% in high-risk patients (strong evidence)
• Reduced rate of actinic keratoses (precancerous lesions)
• Enhanced DNA repair capacity after UV exposure
• Reduced UV-induced immunosuppression
• May reduce photodamage and photoageing markers

Skin cancer prevention (studied dose): 500mg nicotinamide twice daily (1,000mg total). This is the dose used in the landmark ONTRAC trial.

General skin support: 250–500mg daily may provide NAD+-boosting benefits, though this lower dose is less studied for skin-specific outcomes.

Note on form: Nicotinamide (niacinamide) is the form studied for skin. Nicotinic acid (niacin) causes flushing and is NOT interchangeable for this purpose. Ensure your supplement specifies “nicotinamide” or “niacinamide,” not “niacin” or “nicotinic acid.”

Timing: Can be taken at any time with or without food. Split dosing (500mg morning, 500mg evening) maintains more stable NAD+ levels than a single 1,000mg dose.

Important: Benefits appear to be continuous rather than cumulative — they require ongoing supplementation. In the ONTRAC trial, protective effects disappeared within 6 months of stopping.

Required: Nicotinamide (niacinamide) — NOT nicotinic acid (niacin). This distinction is critical. Nicotinic acid causes vasodilatory flushing, does not have the same evidence for skin cancer prevention, and is used for cholesterol management, not skin health.

NR (Nicotinamide Riboside) and NMN: These are alternative NAD+ precursors marketed at premium prices. While they raise NAD+ levels, there is currently no evidence they are superior to plain nicotinamide for skin cancer prevention or DNA repair outcomes. Nicotinamide is far cheaper and has the direct clinical evidence.

Format: Simple tablets or capsules. No need for specialised delivery systems.

Oral nicotinamide and topical niacinamide address different mechanisms. Topical niacinamide (4–5%) primarily supports the skin barrier, reduces sebum, and improves pigmentation through local effects in the epidermis. Oral nicotinamide (500mg+) primarily boosts systemic NAD+ levels for DNA repair and immune protection.

Using both is complementary, not redundant. A protocol combining topical niacinamide (for barrier and oil control) with oral nicotinamide (for DNA repair and cancer prevention) addresses skin health from both local and systemic angles.

With sunscreen: Oral nicotinamide enhances the body’s ability to repair UV damage that gets past sunscreen. Sunscreen prevents most UV damage; nicotinamide helps repair what gets through. This is an additive protection strategy, not a replacement for either component.

With topical retinoids: Retinoids increase cell turnover and may increase UV sensitivity. Oral nicotinamide’s DNA repair support is particularly relevant for retinoid users who may have increased susceptibility to UV damage.

With topical vitamin C: Both provide photoprotection support through different mechanisms (vitamin C as an antioxidant neutralising free radicals, nicotinamide supporting DNA repair). They are complementary.

• Confusing nicotinamide with nicotinic acid (niacin) — these are different supplements with different effects
• Paying a premium for NR or NMN when plain nicotinamide has the direct clinical evidence
• Using oral B3 as a substitute for sunscreen rather than a complement
• Stopping supplementation and expecting continued protection — benefits are not permanent
• Thinking topical and oral niacinamide do the same thing

Chen et al. (ONTRAC trial, 2015): 386 high-risk patients, 500mg nicotinamide twice daily for 12 months. Non-melanoma skin cancer rate reduced by 23%, actinic keratoses reduced by 11% compared to placebo. Landmark phase III RCT. (New England Journal of Medicine)

Surjana et al. (2012): Phase II study showing oral nicotinamide (500mg twice daily) reduced actinic keratoses by 35% and new non-melanoma skin cancers by 50% at 4 months in high-risk patients. (Journal of Investigative Dermatology)

Thompson et al. (2021): Follow-up analysis confirming ONTRAC results and noting that benefits ceased within 6 months of discontinuation, supporting the need for ongoing supplementation. (Journal of the American Academy of Dermatology)