NutriDex

The Supplement Research Compendium
⚡

Vitamin B3 (Niacin)

Nicotinic acid

Essential for NAD/NADP energy metabolism; a powerful but disappointing lipid drug.

Strong evidence 🍊Vitamin

✚ Updated · How we grade evidence

Evidence tier
Strong
Research weight
Citations
10 verified / 10
Classification
Vitamin
❝
What the evidence says. Multiple high-quality RCTs / meta-analyses with consistent effects.

What is Vitamin B3 (Niacin)?

Vitamin B3 (Niacin) (Nicotinic acid) is a vitamin used for prevents and cures niacin deficiency (pellagra: dermatitis, diarrhea, dementia) - the only firmly established benefit. NutriDex grades the human evidence as Strong. Niacin (vitamin B3) is the precursor of NAD+ and NADP+, coenzymes central to hundreds of redox and energy-metabolism reactions; severe deficiency causes pellagra (dermatitis, diarrhea, dementia, and death). Dietary or low-dose supplementation reliably prevents and cures deficiency, which is now rare in fortified-food countries. At pharmacologic doses (1-2 g/day) nicotinic acid markedly raises HDL and lowers triglycerides and Lp(a), but the large statin-era RCTs AIM-HIGH and HPS2-THRIVE found NO reduction in cardiovascular events, and HPS2-THRIVE plus a Cochrane review (~35,500 patients) showed excess harms (new-onset diabetes, infection, bleeding, GI/musculoskeletal effects). Niacin should therefore be used to correct deficiency, not as a routine cardiovascular or "cholesterol" supplement in non-deficient people.

Purported Benefits

✓Prevents and cures niacin deficiency (pellagra: dermatitis, diarrhea, dementia) - the only firmly established benefit
✓Corrects deficiency states from malnutrition, alcohol-use disorder, malabsorption, carcinoid syndrome, and Hartnup disease
✓Pharmacologic nicotinic acid (1-2 g/day) raises HDL-C, lowers triglycerides and lipoprotein(a) - but these surrogate changes did NOT translate into fewer cardiovascular events in statin-treated patients (AIM-HIGH, HPS2-THRIVE)
✓Nicotinamide (a different B3 form) reduces new keratinocyte skin cancers in high-risk patients (ONTRAC trial) - distinct from niacin's lipid uses
✓Not recommended as a general supplement for healthy, non-deficient adults; Cochrane found no mortality or CVD benefit and meaningful side-effect-driven discontinuation

Evidence by outcome

The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.

OutcomeEvidenceEffectStudies
Prevention/cure of deficiency (pellagra)The only firmly established benefit; low-dose niacin reliably cures pellagra, though deficiency is now rare in fortified-food countries. Strong ↑ benefit · large 1
Cardiovascular event prevention (pharmacologic doses)Two large statin-era RCTs (AIM-HIGH, HPS2-THRIVE n=25,673), Cochrane, and a 119-trial meta-analysis show no CV-event or mortality benefit despite favorable lipid changes. Strong — no effect · negligible 4
Lipid surrogates (raise HDL, lower TG/Lp(a)/apoB)Robustly raises HDL and lowers triglycerides/Lp(a)/apoB; but these surrogate gains did not translate into clinical CV benefit. Strong ↑ benefit · moderate 3
Adverse effects at pharmacologic doses (diabetes, AEs)HPS2-THRIVE showed new-onset diabetes (HR 1.32) and serious AEs; Cochrane found ~18% discontinued for side effects. Strong ⚠ risk · moderate 2
Skin cancer prevention (nicotinamide)ONTRAC trial cited: nicotinamide (a different B3 form) cut new keratinocyte cancers in high-risk patients; distinct from niacin's lipid uses. Preliminary ↑ benefit · moderate 1
Inflammation (CRP reduction)Meta-analysis of 15 RCTs found significant CRP reduction (SMD -0.88), strongest at <=1000 mg/day with elevated baseline CRP; clinical relevance unproven. Moderate ↑ benefit · moderate 1

Dosing & Compounds

Typical Dose
Adult RDA 16 mg NE/day (men) and 14 mg NE/day (women); pregnancy 18 mg, lactation 17 mg. Typical multivitamin dose ~20 mg. Pharmacologic lipid dosing is 1-2 g/day of nicotinic acid (prescription only). Tolerable Upper Intake Level (UL) for supplemental/fortification niacin is 35 mg/day for adults, set on the basis of flushing; this UL does not apply to clinician-supervised therapeutic use.
Active Compounds
Nicotinic acid (niacin) - immediate-release and prescription extended-release; causes flushingNicotinamide / niacinamide - no flushing, no lipid effect; used in dermatologyInositol hexanicotinate ('no-flush niacin') - poorly converted, little proven effectDietary sources: meat, poultry, fish (tuna, salmon), liver, peanuts, legumes, whole and enriched/fortified grains, mushrooms; also synthesized endogenously from tryptophan (60 mg tryptophan = 1 mg niacin equivalent)

Safety & Cautions

Low-dose dietary niacin is safe. Nicotinic acid above ~30-50 mg causes cutaneous flushing, itching, and headache (basis of the 35 mg/day UL); aspirin 30 min before and slow titration reduce flushing. Gram-level therapeutic doses can cause hepatotoxicity (especially sustained/extended-release forms), hyperglycemia and new-onset diabetes (HPS2-THRIVE diabetes HR 1.32, 95% CI 1.16-1.51), hyperuricemia/gout, GI upset, and myopathy. HPS2-THRIVE also found excess serious infections and bleeding. Adding niacin to statins gave NO cardiovascular benefit (AIM-HIGH HR 1.02; HPS2-THRIVE neutral) and is no longer recommended for CVD prevention. Interactions: additive with statins (myopathy), can blunt glycemic control in diabetes, may potentiate antihypertensives/vasodilators (hypotension), and reduces uricosuric drug efficacy. Observational 2024 work links the niacin terminal metabolite 4PY to vascular inflammation and major adverse cardiac events. Educational only — always check with your doctor or pharmacist before combining Vitamin B3 (Niacin) with any medicine.

Vitamin B3 (Niacin) drug interactions

Known or theoretical interactions between Vitamin B3 (Niacin) and common medications — educational, not exhaustive. Always check with your doctor or pharmacist before combining Vitamin B3 (Niacin) with any medicine.

Caution
Statins
High-dose niacin with statins increases risk of myopathy and rhabdomyolysis.
Additive myotoxicity; niacin may also impair muscle metabolism. NIH ODS — Niacin
Monitor
Insulin & oral antidiabetics
High-dose niacin can raise blood glucose and worsen glycemic control.
Niacin reduces insulin sensitivity and increases hepatic glucose output at pharmacologic doses. NIH ODS — Niacin

Key Studies ★ 10 studies

Meta-analysis Nikookar/Hosseini 2024 (Eur J Nutr) ✓ PubMed
Meta-analysis of 15 RCTs found niacin significantly reduced C-reactive protein (SMD -0.88, 95% CI -1.46 to -0.30, p=0.003), with effects strongest at doses <=1000 mg/day and elevated baseline CRP (>3 mg/L).
Meta-analysis Haskey 2024 (Br J Nutr) ✓ Source
Systematic review and meta-analysis of RCTs quantifying niacin's effects on apolipoprotein A1 and apolipoprotein B levels, supporting its lipid-modifying (HDL-raising, apoB-lowering) profile.
Cochrane systematic review Schandelmaier, Cochrane Review 2017 ✓ Full text
Across ~35,500 patients niacin did not reduce all-cause mortality (RR 1.05, 95% CI 0.97-1.12) or CV events, with ~18% stopping for side effects; no role in CVD prevention.
systematic review & meta-analysis D'Andrea et al., JAMA Network Open 2019 ✓ Full text
Meta-analysis of 119 trials (35,760 participants) found niacin did not prevent cardiovascular disease overall in the modern statin era.
systematic review & meta-analysis UL dose-response meta-analysis, 2017 (PMID 28541582) ✓ PubMed
Systematic review/meta-analysis of dose-dependent effects of nicotinic acid and nicotinamide informing the niacin tolerable upper intake level.
large RCT HPS2-THRIVE, NEJM 2014 ✓ Source
In 25,673 statin-treated patients, ER niacin/laropiprant did not reduce major vascular events and increased serious adverse effects, including new-onset diabetes (HR 1.32, 95% CI 1.16-1.51).
large RCT AIM-HIGH Investigators, NEJM 2011 ✓ Source
In 3,414 statin-treated patients, ER niacin raised HDL and lowered triglycerides but gave no CV benefit (HR 1.02, 95% CI 0.87-1.21); stopped early for futility.
observational + mechanistic study Ferrell/Hazen et al., Nature Medicine 2024 ✓ Source
The niacin terminal metabolite 4PY was associated with elevated 3-year major adverse cardiovascular event risk and shown to drive vascular inflammation in models.
Observational NHANES dietary niacin 2024 (Sci Rep) ✓ Source
Cross-sectional/cohort analysis of 26,746 US adults (NHANES 2003-2018) found higher dietary niacin intake associated with lower all-cause and cardiovascular mortality, with the highest intake quartile showing reduced all-cause mortality risk.
authoritative body NIH ODS Niacin Fact Sheet (2023) ✓ Source
RDA 16 mg NE/day (men) and 14 mg NE/day (women); UL 35 mg/day based on flushing; severe deficiency causes pellagra.
10 sources cited · 10 verified Search all studies on PubMed ↗

Common questions about Vitamin B3 (Niacin)

What is Vitamin B3 (Niacin) used for?

Vitamin B3 (Niacin) is most often taken for Prevents and cures niacin deficiency (pellagra: dermatitis, diarrhea, dementia) - the only firmly established benefit, Corrects deficiency states from malnutrition, alcohol-use disorder, malabsorption, carcinoid syndrome, and Hartnup disease, Pharmacologic nicotinic acid (1-2 g/day) raises HDL-C, lowers triglycerides and lipoprotein(a) - but these surrogate changes did NOT translate into fewer cardiovascular events in statin-treated patients (AIM-HIGH, HPS2-THRIVE), Nicotinamide (a different B3 form) reduces new keratinocyte skin cancers in high-risk patients (ONTRAC trial) - distinct from niacin's lipid uses. Essential for NAD/NADP energy metabolism; a powerful but disappointing lipid drug.

Does Vitamin B3 (Niacin) work — what does the evidence say?

Strong evidence. Multiple high-quality RCTs / meta-analyses with consistent effects. Niacin (vitamin B3) is the precursor of NAD+ and NADP+, coenzymes central to hundreds of redox and energy-metabolism reactions; severe deficiency causes pellagra (dermatitis, diarrhea, dementia, and death). Dietary or low-dose supplementation reliably prevents and cures deficiency, which is now rare in fortified-food countries. At pharmacologic doses (1-2 g/day) nicotinic acid markedly raises HDL and lowers triglycerides and Lp(a), but the large statin-era RCTs AIM-HIGH and HPS2-THRIVE found NO reduction in cardiovascular events, and HPS2-THRIVE plus a Cochrane review (~35,500 patients) showed excess harms (new-onset diabetes, infection, bleeding, GI/musculoskeletal effects). Niacin should therefore be used to correct deficiency, not as a routine cardiovascular or "cholesterol" supplement in non-deficient people.

What is the typical dose of Vitamin B3 (Niacin)?

Adult RDA 16 mg NE/day (men) and 14 mg NE/day (women); pregnancy 18 mg, lactation 17 mg. Typical multivitamin dose ~20 mg. Pharmacologic lipid dosing is 1-2 g/day of nicotinic acid (prescription only). Tolerable Upper Intake Level (UL) for supplemental/fortification niacin is 35 mg/day for adults, set on the basis of flushing; this UL does not apply to clinician-supervised therapeutic use.

Is Vitamin B3 (Niacin) safe? Any cautions or side effects?

Low-dose dietary niacin is safe. Nicotinic acid above ~30-50 mg causes cutaneous flushing, itching, and headache (basis of the 35 mg/day UL); aspirin 30 min before and slow titration reduce flushing. Gram-level therapeutic doses can cause hepatotoxicity (especially sustained/extended-release forms), hyperglycemia and new-onset diabetes (HPS2-THRIVE diabetes HR 1.32, 95% CI 1.16-1.51), hyperuricemia/gout, GI upset, and myopathy. HPS2-THRIVE also found excess serious infections and bleeding. Adding niacin to statins gave NO cardiovascular benefit (AIM-HIGH HR 1.02; HPS2-THRIVE neutral) and is no longer recommended for CVD prevention. Interactions: additive with statins (myopathy), can blunt glycemic control in diabetes, may potentiate antihypertensives/vasodilators (hypotension), and reduces uricosuric drug efficacy. Observational 2024 work links the niacin terminal metabolite 4PY to vascular inflammation and major adverse cardiac events.

How many studies support Vitamin B3 (Niacin)?

NutriDex cites 10 sources for Vitamin B3 (Niacin), graded "Strong".

Does Vitamin B3 (Niacin) interact with any medications?

Yes — known or theoretical interactions include: Statins (cholesterol drugs) (caution), Diabetes drugs (insulin, metformin) (monitor). This is educational and not exhaustive; always check with your doctor or pharmacist before combining Vitamin B3 (Niacin) with any medicine.

Cite this page
APA

Peh, D. (2026). Vitamin B3 (Niacin) (Nicotinic acid): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 2026, from https://nutridex.info/s/vitamin-b3-niacin

BibTeX
@misc{nutridex_vitamin_b3_niacin,
  author       = {Peh, Daryl},
  title        = {Vitamin B3 (Niacin) (Nicotinic acid): Benefits, Dosage, Side Effects \& Evidence},
  year         = {2026},
  howpublished = {NutriDex --- The Supplement Research Compendium},
  url          = {https://nutridex.info/s/vitamin-b3-niacin},
  note         = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

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