For general education, not medical advice. This guide can’t diagnose you or replace care from your own clinician. If you’re worried about a spot or symptom, see a board-certified dermatologist.
Nicotinamide is a form of vitamin B3, also called niacinamide. It is sold over the counter as a cheap supplement. In people who keep getting skin cancers, taking it every day can lower the number of new ones. This guide explains who it helps, how much the trials showed, who it does not help, and honest answers about niacin, melanoma, and safety.
Key points
- In a one-year randomized trial of people who had already had at least two skin cancers, nicotinamide led to about 23% fewer new non-melanoma skin cancers than a dummy pill.1
- The benefit was shown in people with a normal immune system. A trial built for transplant patients found no benefit.2
- It is an add-on for higher-risk people, used alongside sun protection and skin checks, not a replacement for them.3
What nicotinamide is, and how it differs from niacin
Nicotinamide is a water-soluble form of vitamin B3.3 The body uses it to keep cells powered. Sun harms skin partly by draining that energy and by weakening the skin's local defenses. Vitamin B3 helps the skin keep its energy, repair sun-damaged DNA, and hold those defenses.45
One point causes a lot of confusion. It is not the same as niacin. Niacin (also called nicotinic acid) is a different form of B3. It is the one used for cholesterol, and it causes the warm, red flushing many people know. Nicotinamide does not flush, and it is the form studied for skin cancer.3 A bottle labeled "niacin" is the wrong form.
Who it helps, and who it does not
The evidence comes mainly from two randomized trials, one in people with a normal immune system and one in transplant patients. They reached opposite results, which is the most important thing to understand. Here is what nicotinamide did, outcome by outcome.
In a one-year randomized trial of people who had already had at least two skin cancers, taking nicotinamide twice a day led to about 23% fewer new non-melanoma skin cancers than a dummy pill. When several trials were pooled, the reduction looked larger, about half, though that pooled estimate is less certain because the studies varied. The benefit is real but modest, and it fades once the pills stop.
Most of the benefit fell on the squamous cell side, with about 30% fewer of these cancers in the trial, a result that just reached the line for proof. A review that pooled studies points the same way for squamous cell cancer.
The evidence here conflicts. In the main trial the roughly 20% drop in basal cell carcinoma did not reach the line for proof, and a later, broader pooled review found no clear basal cell effect. But an earlier pooled review did find a significant drop in basal cell cancers. So a basal cell benefit is possible but not settled.
People taking nicotinamide had fewer precancers while on it, about 13% fewer at one year in the trial, and earlier studies pointed the same way. The effect lasts only while you keep taking it.
A trial built for transplant recipients found no benefit, with the same number of new skin cancers in the nicotinamide and placebo groups. The protection seen in people with a normal immune system did not carry over, so nicotinamide is not a substitute for close skin checks after a transplant.
Whole-body prevention, separate from the spot treatments above. “No effect” means good trials found no benefit. Every source is PubMed-verified; not medical advice.
A few honest notes on this table. The clearest win is against squamous cell cancer and precancers, in high-risk people with a normal immune system.1 The basal cell result is mixed. In the main trial the roughly 20% drop did not reach the line for proof, and a later pooled review found no clear basal cell effect. But an earlier pooled review did find a real drop.167 When trials were pooled, the overall skin-cancer reduction looked larger, about half. That figure is less certain, because the studies varied.6 The short version: a modest benefit for high-risk people with a normal immune system, best against squamous cell cancer, that you have to keep taking to keep.
If you have had a transplant, read this first
People who have had an organ transplant have the highest skin-cancer risk of anyone. The medicines that protect the new organ also lower the body's defense against cancer. So you might assume vitamin B3 must help them most. A trial was built to test that question, and the answer was no. There was no difference in new skin cancers between the people who took it and the people who took a dummy pill.2 Earlier reviews had already found the transplant evidence was thin.8
So if you are immune-suppressed, the benefit seen in other patients did not carry over to you. Nicotinamide is not a substitute for the close skin checks and the plan your transplant team and dermatologist set for you. It is reasonable to ask them whether it has any role in your case, but do not count on it to prevent skin cancer on its own.
Other options and questions patients ask about
People often arrive having read that vitamin B3 prevents all skin cancers, or having mixed it up with other pills. Here are the honest answers.
- "Does it prevent melanoma?" There is no trial showing that. It repairs sun-damaged DNA, which is why researchers hope it might help against melanoma too.5 But the main trials measured the common skin cancers, not melanoma, and pooled reviews did not find a melanoma benefit.7 The honest answer: a reasonable idea, not yet proven. Do not rely on a B3 pill to prevent melanoma.
- "Will a niacinamide face serum do the same thing?" No. The skin-cancer evidence is for the pill taken by mouth at a set dose. Niacinamide is a fine ingredient in skin care, but no study shows a serum lowers skin cancer.
- "Are the anti-aging NAD pills (NR or NMN) the same?" They are related B3 products marketed for longevity, but they are not the form tested for skin cancer, and they have no skin-cancer trials behind them.
- "Is it safe to take a lot of vitamin B3?" In the trials, 500 mg twice a day was well tolerated over a year.1 Still, more is not better. A 2024 study tied the breakdown products of very high B3 intake to higher heart risk. This is an early signal, not proof. It is a reason to stick to the studied dose, not to mega-dose on your own.9 Talk it over with your doctor first.
Who should consider it
Nicotinamide makes the most sense for people who keep getting skin cancers or precancers and have a normal immune system. It is inexpensive and easy to take. Two things to keep in mind:
- It is sold as an over-the-counter supplement. It is not an approved drug for preventing skin cancer, so this is an evidence-based, off-label use that is best started with your dermatologist's guidance.
- It is an add-on, not a swap. It works alongside daily sun protection, sun-smart habits, and regular skin exams, which remain the foundation. See our guides on sunscreen and the skin cancers it helps prevent.
When to see a doctor
Nicotinamide lowers risk for some people, but it does not erase it, and it does nothing to find a cancer that is already there. Have a dermatologist check any spot that is new, growing, changing color, bleeding, or not healing. If you have had many skin cancers, a lot of sun, or a transplant, ask how often you should have a full skin exam. Catching a skin cancer early is still the most reliable way to keep it small and easy to treat.
Worried about a spot?
SpotDoc offers full-body skin cancer screening in Brownwood Square, The Villages. No referral needed for most plans.
Frequently asked questions
How much nicotinamide was used in the studies? The main trial used 500 mg taken twice a day. Talk with your doctor before starting, especially about the right form and dose for you.
Is nicotinamide the same as niacin? No. They are both vitamin B3, but niacin (nicotinic acid) is the form used for cholesterol that causes flushing. Nicotinamide does not cause that flushing, and it is the form studied for skin cancer. Buying "niacin" by mistake gives you the wrong one.
Does it work if I have had a transplant? A trial designed for transplant patients did not find a benefit. If you are immune-suppressed, do not count on it, and keep up the skin checks your transplant team recommends.
Does nicotinamide prevent melanoma? There is no trial showing it prevents melanoma. The proven benefit is for the more common non-melanoma skin cancers in high-risk people, and even there the effect is modest.
Do I still need sunscreen if I take it? Yes. Nicotinamide is an add-on for higher-risk people, not a replacement for sun protection and skin exams.
How long do I need to take it? The benefit lasts only while you keep taking it. In the trial, the protection faded after the pills were stopped.
Questions to ask your dermatologist
- Given my history, am I likely to benefit from nicotinamide?
- What dose and form do you recommend, and are there reasons I should not take it?
- I have had a transplant. Does it have any role for me?
- How does this fit with my sun protection and skin-exam plan?
- What kind of spot should make me call the office sooner?
Reviewed by Tyler Long, DO. Last reviewed June 2026.
Update log
How this guide has changed since it was first published.
- October 27, 2026Guide published.
References
Every statement on this page is backed by the peer-reviewed sources below — each links to the original study. Numbers match the citations in the text and the grids above.
- Chen AC, Martin AJ, Choy B, et al. A Phase 3 Randomized Trial of Nicotinamide for Skin-Cancer Chemoprevention. N Engl J Med. 2015;373(17):1618–1626.View source
- Allen NC, Martin AJ, Snaidr VA, et al. Nicotinamide for Skin-Cancer Chemoprevention in Transplant Recipients. N Engl J Med. 2023;388(9):804–812.View source
- Snaidr VA, Damian DL, Halliday GM. Nicotinamide for photoprotection and skin cancer chemoprevention: A review of efficacy and safety. Exp Dermatol. 2019;28(Suppl 1):15–22.View source
- Pilkington SM, Gibbs NK, Friedmann PS, Rhodes LE. Nutritional abrogation of photoimmunosuppression: in vivo investigations. Photodermatol Photoimmunol Photomed. 2014;30(2-3):112–127.View source
- Minocha R, Damian DL, Halliday GM. Melanoma and nonmelanoma skin cancer chemoprevention: A role for nicotinamide? Photodermatol Photoimmunol Photomed. 2017;34(1):5–12.View source
- Mainville L, Smilga AS, Fortin PR. Effect of Nicotinamide in Skin Cancer and Actinic Keratoses Chemoprophylaxis, and Adverse Effects Related to Nicotinamide: A Systematic Review and Meta-Analysis. J Cutan Med Surg. 2022;26(3):297–308.View source
- Tosti G, Pepe F, Gnagnarella P, et al. The Role of Nicotinamide as Chemo-Preventive Agent in NMSCs: A Systematic Review and Meta-Analysis. Nutrients. 2023;16(1):100.View source
- Chung EYM, Palmer SC, Strippoli GFM. Interventions to Prevent Nonmelanoma Skin Cancers in Recipients of a Solid Organ Transplant: Systematic Review of Randomized Controlled Trials. Transplantation. 2019;103(6):1206–1215.View source
- Ferrell M, Wang Z, Anderson JT, et al. A terminal metabolite of niacin promotes vascular inflammation and contributes to cardiovascular disease risk. Nat Med. 2024;30(2):424–434.View source
- Surjana D, Halliday GM, Martin AJ, Moloney FJ, Damian DL. Oral nicotinamide reduces actinic keratoses in phase II double-blinded randomized controlled trials. J Invest Dermatol. 2012;132(5):1497–1500.View source