Niacin vs Nicotinamide

Written by Aaron CuhaReviewed Sep 2026

The short answer

Two forms of vitamin B3 that are often treated as the same and are not. One has been tested for heart attacks and strokes in more than 29,000 people and prevented none. The other cut new skin cancers, not counting melanoma, by 23 percent over 12 months in a large final stage trial, and it does not cause flushing.

Niacin people: 29,087
Niacin nulls: 0
Nicotinamide people: 591
Nicotinamide nulls: 4

Dose

Approved medicine. No human dose established for unlabelled uses

Labeled amounts sit on the prescribing information. This page records what trials measured, not a personal dose.

Slow-release nicotinic acid is an FDA-approved prescription cholesterol drug in the United States. But doctors mostly stopped using it after two large studies, AIM-HIGH and HPS2-THRIVE. Lower-dose nicotinic acid is also sold over the counter as a supplement. The mix of slow-release niacin and laropiprant tested in HPS2-THRIVE was pulled from sale worldwide after that study reported.

Dose

No human dose established

Amounts that were given in studies sit in Human evidence on this page. None of them is a personal dose.

4 completed trials, 591 people given it

First-hand reports are counted on each profile and never added together. This page sets two published records side by side. It does not pick a winner.

Column A

Niacin

Nicotinic acid, niacin, the acid form of vitamin B3

The only NAD-pathway product ever tested against real heart outcomes, in 25,673 people in HPS2-THRIVE and 3,414 in AIM-HIGH. It moved every blood fat it was meant to move. It prevented no heart attacks or strokes in either study. In HPS2-THRIVE it caused extra serious side effects, including infections and bleeding.

Column B

Nicotinamide

Nicotinamide, the amide form of vitamin B3

A plain form of vitamin B3. In a large final-stage study of 386 people at high risk, 500 mg twice a day cut new skin cancers other than melanoma by 23 percent over 12 months. The benefit stopped once the pills stopped. The same study in 158 organ transplant patients found nothing. No study has ever tested it against ageing.

The mistake this page exists to correct

Niacin and nicotinamide are sold as the same vitamin and are often swapped in supplement write ups and in NAD marketing. They act differently. Niacin lowers LDL, raises HDL and causes flushing. Nicotinamide does none of those. Niacin is the only NAD pathway compound ever tested for heart attacks and strokes, in 25,673 patients in HPS2-THRIVE and 3,414 in AIM-HIGH. It prevented none, and HPS2-THRIVE found more serious side effects, including infection and bleeding. Nicotinamide's strongest result is in preventing skin cancer, and it vanished once people stopped the tablets. Neither result carries over to the other molecule.

Side by side, on the facts we can check

What we compare	Niacin	Nicotinamide
Category	Longevity	Longevity
FDA status	Slow-release nicotinic acid is an FDA-approved prescription cholesterol drug in the United States. But doctors mostly stopped using it after two large studies, AIM-HIGH and HPS2-THRIVE. Lower-dose nicotinic acid is also sold over the counter as a supplement. The mix of slow-release niacin and laropiprant tested in HPS2-THRIVE was pulled from sale worldwide after that study reported.	Not an approved drug for preventing skin cancer in the United States. It is a standard form of the vitamin niacin. It is sold over the counter and found in multivitamins and skin care products. The dose used in the ONTRAC study is an over-the-counter dose, used off label, meaning outside any approved use.
Half-life	Under an hour for immediate-release nicotinic acid. Extended-release formulations were built specifically to stretch that out and blunt the flush, and the dose is not interchangeable between forms.	About 4 hours in plasma, which is why the skin cancer trials dosed it twice a day rather than once.
Molecular weight	123.1 Da	122.1 Da
How it works	Niacin gets turned into NAD by its own route, called the Preiss-Handler pathway, not the NAMPT recycling route. That is why it is a strong NAD booster. A 2026 study in people suggested gut bacteria may turn NR and NMN into niacin, and that this may be how those two pricey products work at all. Niacin's effect on blood fats is separate. It mainly slows the release of fat from fat cells and slows fat-making in the liver. So less fat flows to the liver, and the liver sends out fewer fat-carrying particles. The flush is a third, separate action. Niacin switches on a receptor called GPR109A on immune cells in the skin. They release chemicals called prostaglandins that open up the skin's blood vessels. Work in mice with genes switched off proved each link in that chain. The laropiprant in HPS2-THRIVE blocked one of those prostaglandins to stop the flush. It stopped the flush and did nothing for the outcomes.	Nicotinamide is turned back into NAD by the recycling route. First an enzyme called NAMPT turns it into NMN. Then other enzymes turn NMN into NAD. NAMPT is the slow step. So more nicotinamide does not mean more NAD in a straight line. The bottleneck is the enzyme, not the supply. Separately, nicotinamide is what is left when sirtuins, PARPs and CD38 use up NAD. It then blocks sirtuins by sitting in a pocket next to where NAD binds, which switches the enzyme away from its normal job. In skin, the cancer-prevention effect works a different way again and does not depend on NAD in the blood at all. Nicotinamide helps repair DNA damaged by sunlight, and it eases the way sunlight weakens the skin's immune defence.
Studies in people	5	4
Evidence	Strong: 2 completed trials, 29,087 people given it	Moderate: 4 completed trials, 591 people given it
Legal status, US	FDA-approved prescription cholesterol drug, also sold over the counter as a supplement	Sold as a supplement

open the Niacin profile open the Nicotinamide profile

Frequently asked questions

What is the difference between Niacin and Nicotinamide?

Niacin: The only NAD-pathway product ever tested against real heart outcomes, in 25,673 people in HPS2-THRIVE and 3,414 in AIM-HIGH. It moved every blood fat it was meant to move. It prevented no heart attacks or strokes in either study. In HPS2-THRIVE it caused extra serious side effects, including infections and bleeding. Nicotinamide: A plain form of vitamin B3. In a large final-stage study of 386 people at high risk, 500 mg twice a day cut new skin cancers other than melanoma by 23 percent over 12 months. The benefit stopped once the pills stopped. The same study in 158 organ transplant patients found nothing. No study has ever tested it against ageing.

Which has stronger research evidence, Niacin or Nicotinamide?

Each compound gets a band worked out from facts we counted, with the math shown. Niacin is Strong (2 completed trials, 29,087 people given it). Nicotinamide is Moderate (4 completed trials, 591 people given it). That counts how much has been done in people. It does not rate whether either one works, and neither one is called the winner.

Are Niacin and Nicotinamide FDA-approved?

Niacin: Slow-release nicotinic acid is an FDA-approved prescription cholesterol drug in the United States. But doctors mostly stopped using it after two large studies, AIM-HIGH and HPS2-THRIVE. Lower-dose nicotinic acid is also sold over the counter as a supplement. The mix of slow-release niacin and laropiprant tested in HPS2-THRIVE was pulled from sale worldwide after that study reported.. Nicotinamide: Not an approved drug for preventing skin cancer in the United States. It is a standard form of the vitamin niacin. It is sold over the counter and found in multivitamins and skin care products. The dose used in the ONTRAC study is an over-the-counter dose, used off label, meaning outside any approved use..

Reviewed Sep 2026. This page puts two published records side by side. It is for learning, and it is not medical advice. When this site shows a dose, it is the dose a trial or a clinic actually used, or what people say they did, with the source attached. None of it tells you what to take.