Niacin
Niacin raised HDL and lowered triglycerides and LDL. In AIM-HIGH and HPS2-THRIVE, added to statins, it did not lower heart attacks, strokes or deaths. Pooled trials found 34% more new diabetes. HPS2-THRIVE found more serious side effects. Sustained-release niacin caused liver toxicity in half of one trial's patients. Nicotinamide lowered new skin cancers in one trial.
Add to Bio HackChecked 2026-11-09
- Status
- Dietary supplement in the US. Extended-release nicotinic acid is also a prescription drug in the US for abnormal blood lipids. In the EU, the nicotinic acid with laropiprant products were suspended in 2013.
- Also called
- vitamin B3, nicotinic acid, nicotinamide, niacinamide, extended-release niacin, sustained-release niacin, flush-free niacin, inositol hexanicotinate, Niaspan
- Taken for
- cholesterol, HDL, triglycerides, heart health, skin cancer prevention, skin, energy, detox
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Shown to help3
- ModerateShown to raise HDL and lower triglycerides and LDL in people with vascular disease on statins, though events did not fall.
- LimitedOne trial from before statins found 11% lower mortality at 15 years in men after a heart attack, appearing after treatment had stopped.
- LimitedOne trial found 23% fewer new nonmelanoma skin cancers on nicotinamide in high-risk adults, with no benefit after stopping or in transplant recipients.
Reported risks4
- ModerateShown to roughly double stopping for side effects, with flushing the most common reason in one trial.Very common
- LimitedOne small trial found liver toxicity in 52% on sustained-release niacin and none on immediate-release, at doses rising to 3,000 mg a day.Very common
- ModerateShown to raise new-onset diabetes about 34%, one extra case per 43 people treated for 5 years.How often is not known
- LimitedOne trial found more serious gut, muscle, skin, infection and bleeding events with niacin plus laropiprant. EMA suspended these products in 2013.How often is not known
What people take it for, and what was found
Shown to help3
Blood lipids
Shown to raise HDL and lower triglycerides and LDL in people with vascular disease on statins, though events did not fall.
The numbers and sources
- Effect
- At 2 years in AIM-HIGH, median HDL rose from 35 to 42 mg/dL, triglycerides fell from 164 to 122 mg/dL and LDL fell from 74 to 62 mg/dL on 1,500 to 2,000 mg a day of extended-release niacin [1]. In HPS2-THRIVE, LDL averaged 10 mg/dL lower and HDL 6 mg/dL higher than placebo [2].
- Population
- 3,414 people with cardiovascular disease on simvastatin [1]; 25,673 adults with vascular disease on statin-based therapy [2].
- Sources
- [1], [2]
- Caveats
- Lipid changes did not translate into fewer events in these trials (see next block).
Long-term mortality after a heart attack, before statins
One trial from before statins found 11% lower mortality at 15 years in men after a heart attack, appearing after treatment had stopped.
The numbers and sources
- Effect
- At a mean 15 years, about 9 years after the trial ended, mortality was 52.0% in the niacin group and 58.2% on placebo, 11% lower (P = 0.0004). During the trial, niacin lowered nonfatal repeat heart attacks and did not lower total mortality [4].
- Population
- 8,341 men aged 30 to 64 with a prior heart attack, treated 1966 to 1975 [4].
- Sources
- [4]
- Caveats
- One trial from before statins. The mortality difference appeared after treatment stopped [4].
- Why limited
- This rests on one trial, of 8,341 people. Strength counts independent studies that agree, so one trial is limited at any size.
Skin cancer prevention (nicotinamide)
One trial found 23% fewer new nonmelanoma skin cancers on nicotinamide in high-risk adults, with no benefit after stopping or in transplant recipients.
The numbers and sources
- Effect
- Over 12 months, new nonmelanoma skin cancers were 23% lower on nicotinamide 500 mg twice a day than on placebo (95% CI 4 to 38). Squamous-cell carcinomas were 30% lower (95% CI 0 to 51) and basal-cell carcinomas did not significantly differ. Actinic keratoses were 11% to 20% lower. No benefit remained after nicotinamide stopped [5]. A 2026 systematic review pooled 2 RCTs in organ transplant recipients (180 people) and found no significant reduction in keratinocyte cancers (rate ratio 0.97, 95% CI 0.77 to 1.22). In a retrospective cohort of 33,822 patients, nicotinamide use was associated with 14% less skin cancer overall (HR 0.86, 95% CI 0.83 to 0.89) and none in transplant recipients [6].
- Population
- 386 people with at least two nonmelanoma skin cancers in the past 5 years [5]; transplant recipients and a retrospective cohort [6].
- Sources
- [5], [6]
- Caveats
- The benefit in immunocompetent adults rests on one trial, in people at high risk. Funded by Australia's National Health and Medical Research Council [5]. All randomized trials followed people for 12 months or less, and certainty for transplant outcomes was low or very low [6].
Not shown to help1
Heart attack, stroke and death
Not shown to lower heart attacks, strokes or deaths in people with vascular disease, including those on statins.
The numbers and sources
- Effect
- In AIM-HIGH, the primary composite occurred in 16.4% on niacin and 16.2% on placebo (HR 1.02, 95% CI 0.87 to 1.21). The trial stopped at a mean 3 years for lack of efficacy [1]. In HPS2-THRIVE, major vascular events occurred in 13.2% and 13.7% (rate ratio 0.96, 95% CI 0.90 to 1.03) [2]. Across 23 trials, niacin did not change overall mortality (RR 1.05, 95% CI 0.97 to 1.12), heart attacks (RR 0.93, 95% CI 0.87 to 1.00) or strokes (RR 0.95, 95% CI 0.74 to 1.22) [3].
- Population
- 3,414 people [1]; 25,673 adults [2]; 39,195 participants in 23 trials, median dose 2 g a day [3].
- Sources
- [1], [2], [3]
- Caveats
- AIM-HIGH was funded by the US National Heart, Lung, and Blood Institute and Abbott Laboratories [1]. HPS2-THRIVE was funded by Merck and others, and added laropiprant to reduce flushing [2]. The Cochrane authors rated the mortality evidence high quality [3].
Doses studied
AIM-HIGH used 1,500 to 2,000 mg a day of extended-release niacin [1], and HPS2-THRIVE 2 g a day with 40 mg laropiprant [2]. The median dose in the Cochrane review was 2 g a day [3]. The liver trial stepped up from 500 to 3,000 mg a day [7]. The skin cancer trial used 500 mg of nicotinamide twice a day [5]. EFSA sets separate tolerable upper intake levels for adults: 10 mg a day for nicotinic acid and 900 mg a day for nicotinamide. It found the data inadequate to set them for pregnancy and lactation [8].
Risks
Reported risks4
Liver toxicity
One small trial found liver toxicity in 52% on sustained-release niacin and none on immediate-release, at doses rising to 3,000 mg a day.
The numbers and sources
- How common
- Very common: more than 1 in 10 people.
- Effect
- Liver toxicity developed in 12 of 23 people (52%) on sustained-release niacin and none of 23 on immediate-release niacin. 78% on sustained-release withdrew before reaching 3,000 mg a day, often for rising liver enzymes [7].
- Population
- 46 adults with high LDL cholesterol, dose rising from 500 to 3,000 mg a day in 6-week steps [7].
- Sources
- [7]
- Caveats
- One small trial of sustained-release products from 1994.
Flushing and stopping for side effects
Shown to roughly double stopping for side effects, with flushing the most common reason in one trial.
The numbers and sources
- How common
- Very common: more than 1 in 10 people.
- Effect
- Across 17 trials, people on niacin were about twice as likely to stop treatment for side effects (RR 2.17, 95% CI 1.70 to 2.77) [3]. On immediate-release niacin, 39% withdrew before 3,000 mg a day, most often for flushing and other vasodilatory symptoms, fatigue and skin darkening (acanthosis nigricans) [7].
- Population
- 33,539 participants in 17 trials [3]; 23 adults on immediate-release niacin [7].
- Sources
- [3], [7]
- Caveats
- Heterogeneity was high (I² 77%) [3].
New diabetes and loss of glucose control
Shown to raise new-onset diabetes about 34%, one extra case per 43 people treated for 5 years.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Across 11 trials, niacin raised new-onset diabetes (RR 1.34, 95% CI 1.21 to 1.49), one extra case per 43 people treated for 5 years [9]. In HPS2-THRIVE, serious disturbances of diabetes control rose by 3.7 percentage points and new diabetes diagnoses by 1.3 points [2].
- Population
- 26,340 people without diabetes in 11 trials, mean 3.6 years [9]; 25,673 adults [2].
- Sources
- [2], [9]
- Caveats
- The effect did not depend on background statins or laropiprant [9].
Serious side effects, infection and bleeding
One trial found more serious gut, muscle, skin, infection and bleeding events with niacin plus laropiprant. EMA suspended these products in 2013.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Against placebo, niacin with laropiprant raised serious adverse events of the gut (1.0 percentage point), muscles and joints (0.7), skin (0.3), infection (1.4) and bleeding (0.7), all P of .003 or less [2]. EMA suspended these products across the EU in 2013, stating their benefits no longer outweighed their risks [10].
- Population
- 25,673 adults with vascular disease, median 3.9 years [2].
- Sources
- [2], [10]
- Caveats
- One trial of a combination with laropiprant [2].
- Why limited
- This rests on one trial, of 25,673 people. Strength counts independent studies that agree, so one trial is limited at any size.
Claims tested and not found
- That raising HDL with niacin prevents heart attacks in people on statins. HDL rose and cardiovascular events did not fall in AIM-HIGH or HPS2-THRIVE [1][2].
- That niacin lowers mortality. Across 12 trials, overall mortality did not change [3].
- That sustained-release niacin causes fewer side effects than immediate-release. Liver toxicity occurred only on sustained-release, and more people withdrew on it (78% against 39%) [7].
Sources
- AIM-HIGH Investigators, Boden WE, Probstfield JL, et al. Niacin in Patients with Low HDL Cholesterol Levels Receiving Intensive Statin Therapy. New England Journal of Medicine. 2011. https://doi.org/10.1056/NEJMoa1107579
- HPS2-THRIVE Collaborative Group, Landray MJ, Haynes R, et al. Effects of Extended-Release Niacin with Laropiprant in High-Risk Patients. New England Journal of Medicine. 2014. https://doi.org/10.1056/NEJMoa1300955
- Schandelmaier S, Briel M, Saccilotto R, et al. Niacin for primary and secondary prevention of cardiovascular events. Cochrane Database of Systematic Reviews. 2017. https://doi.org/10.1002/14651858.CD009744.pub2
- Canner PL, Berge KG, Wenger NK, et al. Fifteen year mortality in Coronary Drug Project patients: Long-term benefit with niacin. Journal of the American College of Cardiology. 1986. https://doi.org/10.1016/S0735-1097(86)80293-5
- Chen AC, Martin AJ, Choy B, et al. A Phase 3 Randomized Trial of Nicotinamide for Skin-Cancer Chemoprevention. New England Journal of Medicine. 2015. https://doi.org/10.1056/NEJMoa1506197
- Guerra Jiménez AL, Ortegón Garciaherreros JC, Suárez Escobar LP, et al. Oral Nicotinamide for the Secondary Prevention of Cutaneous Squamous Cell Carcinoma and Other Keratinocyte Carcinomas: A Systematic Review. Journal of Skin Cancer. 2026. https://doi.org/10.1155/jskc/8756577
- McKenney JM, Proctor JD, Harris S, et al. A Comparison of the Efficacy and Toxic Effects of Sustained- vs Immediate-Release Niacin in Hypercholesterolemic Patients. JAMA. 1994. https://doi.org/10.1001/jama.1994.03510330050033
- European Food Safety Authority. Overview on Tolerable Upper Intake Levels as derived by the Scientific Committee on Food (SCF) and the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Version 11. 2025. https://www.efsa.europa.eu/sites/default/files/assets/UL_Summary_tables.pdf
- Goldie C, Taylor AJ, Nguyen P, et al. Niacin therapy and the risk of new-onset diabetes: a meta-analysis of randomised controlled trials. Heart. 2016. https://doi.org/10.1136/heartjnl-2015-308055
- European Medicines Agency. Tredaptive, Pelzont and Trevaclyn: referral. 2013. https://www.ema.europa.eu/en/medicines/human/referrals/tredaptive-pelzont-trevaclyn