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📰Read the full Niacin evidence review on GMJ News →Complete clinical article, references and updates on news.gmj.ge. This page is the structured safety summary.⚠ Photosensitive dermatitis + diarrhea + confusion — pellagra until proven otherwise. Begin niacin treatment immediately [3]
⚠ Patient on isoniazid developing skin or neurological symptoms — co-prescribe pyridoxine and consider niacin assessment [3]
⚠ Carcinoid syndrome: tryptophan diverted to serotonin, reducing NAD synthesis — monitor for pellagra [3]
⚠ Extended-release niacin at >2 g/day — hepatotoxicity risk is higher than with immediate-release form [4]
🥗 Food first — build your daily 16 mg NE/ 14 mg
Check the foods you regularly eat — the bar fills toward your daily target.
Chicken breast (85g)10 mg NE
Turkey breast (85g)10 mg NE
Tuna (85g)8.6 mg NE
Salmon (85g)8.6 mg NE
Beef (85g)6.3 mg NE
Peanuts (28g)4.2 mg NE
Mushrooms (½ cup)2.5 mg NE
Brown rice (1 cup)2.6 mg NE
Check your regular foods above
☑ Risk checker
Diet predominantly based on unfortified corn or millet [3]
Chronic alcoholism (impaired absorption and increased catabolism) [3]
Isoniazid therapy without pyridoxine co-administration [3]
Carcinoid syndrome (tryptophan diverted to serotonin synthesis) [3]
Hartnup disease (genetic tryptophan malabsorption) [3]
Crohn disease and other malabsorptive conditions [2]
Prolonged use of 5-fluorouracil or other antimetabolites [3]
Select factors
🔬 Lab interpreter
Recommended test
Urinary N1-methylnicotinamide (NMN excretion)
Urinary N1-methylnicotinamide (NMN excretion)
Reference range / target
>5.8 µmol/day
>5.8 µmol/day
Reflects recent niacin status. Values <5.8 µmol/day suggest deficiency. Not widely available outside research [2].
Full lab monitoring ↓⚕ For professionals — confirm ranges against your local laboratory.
Clinical verdict
Niacin as nicotinamide is a safe, well-tolerated vitamin essential for over 400 enzymatic reactions. Nicotinic acid is the most effective HDL-raising agent but failed to reduce cardiovascular events when added to statins in major trials. Pellagra remains a real diagnosis in alcoholism, malabsorption, and TB treatment without pyridoxine [3] [4] [8].
1 How much do I need?
👤 Adults: Specific dosage data under clinical review
👴 Elderly: Specific dosage data under clinical review
🤰 Pregnancy: Specific dosage data under clinical review
👦 Pediatric: See guidance
Infants 0–6 months: 2 mg/day AI; children 1–3 years: 6 mg NE/day; 4–8 years: 8 mg NE/day [1]. Pellagra in children presents with dermatitis in sun-exposed areas and behavioral changes. Occurs in
🏃 Athletes: Standard dose
⚖️ Obesity: Standard dose
Fat-soluble compounds may require dose adjustment in obesity.
🩺 Renal: Consult specialist
Dose adjustment may be needed in renal impairment.
🌱 Vegan: Standard dose
How to take
🍽 Timing: Take with food to reduce gastrointestinal discomfort. For nicotinic acid, take 325 mg aspirin 30 minutes before to reduce flushing [4].
💊 With food: Food reduces both flushing (nicotinic acid) and GI upset. No specific fat requirement [1].
2 Which form?
| Form | Bioavailability | Vegan | Cost |
|---|---|---|---|
| ['Nicotinamide (niacinamide)', 'preferred', 'Does not cause flushing. Equally effective as a NAD precursor. Preferred for general supplementation and dermatological use [2].'] | Standard | Check label | |
| ['Nicotinic acid', '', 'Causes dose-dependent flushing (prostaglandin-mediated vasodilation). Uniquely effective for dyslipidemia: raises HDL 15–35%, lowers triglycerides 20–50% [4]. Prescription forms available (Niaspan).'] | Standard | Check label | |
| ['Nicotinamide riboside (NR)', '', 'NAD+ precursor that bypasses the nicotinamide pathway. Marketed for anti-aging and NAD+ restoration. Limited clinical trial data in humans [5].'] | Standard | Check label | |
| ['Nicotinamide mononucleotide (NMN)', '', 'Direct NAD+ precursor. Active research for aging and metabolic health. Small human studies show increased NAD+ blood levels [5]. Not yet in clinical guidelines.'] | Standard | Check label |
3 Common questions
What is niacin flush and is it dangerous? ▼
Niacin flush is a prostaglandin-mediated vasodilation caused by nicotinic acid (not nicotinamide). It manifests as flushing, warmth, tingling, and redness of the face and upper body, typically lasting 15–30 minutes [4]. It is uncomfortable but not dangerous. It can be minimized by taking nicotinic acid with food, using extended-release formulations, or pre-treating with aspirin [4].
What is the difference between nicotinic acid and nicotinamide? ▼
Do NR or NMN supplements slow aging? ▼
Nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN) raise NAD+ levels in humans, but no randomized trial has yet demonstrated clinical anti-aging benefits (longevity extension, disease prevention) in humans [5]. Preclinical data are promising but translational evidence is insufficient.
Can diet alone cause pellagra in developed countries? ▼
4 Clinical evidence
Strong
Treatment and prevention of pellagra (dermatitis, diarrhea, dementia) [3]. Dyslipidemia management with nicotinic acid: raises HDL-C by 15–35% (the most effective HDL-raising agent available), lowers triglycerides by 20–50%, and lowers LDL-C by 5–25% [4]. HIGH
Moderate
Nicotinamide for non-melanoma skin cancer prevention: the ONTRAC trial (n = 386) demonstrated a 23% reduction in new non-melanoma skin cancers with 500 mg twice daily over 12 months in high-risk individuals [7]. Nicotinamide for bullous pemphigoid and other dermatological conditions [2]. MODERATE
Insufficient
Cardiovascular event reduction with nicotinic acid added to statins: the AIM-HIGH (n = 3,414) and HPS2-THRIVE (n = 25,673) trials failed to show benefit when nicotinic acid was added to statin therapy, and HPS2-THRIVE showed increased adverse events [8]. NAD+ precursors (NR, NMN) for anti-aging: promising preclinical data but insufficient human clinical evidence [5]. Alzheimer disease prevention [2]. LOW
5 Safety, toxicity & adverse events
Absolute contraindications
✕ Active liver disease or unexplained transaminase elevation — niacin is hepatotoxic at pharmacological doses
✕ Active peptic ulcer — niacin increases gastric acid secretion
Relative
⚠ Gout — niacin raises uric acid by competing for renal tubular excretion
⚠ Diabetes — pharmacological niacin worsens glycemic control (raises fasting glucose 5–10%)
⚠ Concurrent statin therapy — increased myopathy risk (especially with sustained-release niacin)
🚩 Red flags
● Photosensitive dermatitis in sun-exposed distribution + GI symptoms + confusion — pellagra. Treat with nicotinamide 100 mg TID [3]
● Patient on sustained-release niacin with nausea, fatigue, and jaundice — check LFTs immediately [4]
● Isoniazid patient with new skin rash and diarrhea — assess for pellagra [3]
● Carcinoid tumor patient with unexplained dermatitis — niacin deficiency from tryptophan diversion [3]
6 Interactions
Drug interactions
HMG-CoA reductase inhibitors (statins) Major
Mechanism: Both statins and nicotinic acid can cause myopathy and hepatotoxicity. Additive risk when combined. [4] [8]
Effect: Increased risk of myalgia, rhabdomyolysis, and liver enzyme elevation. AIM-HIGH and HPS2-THRIVE showed no cardiovascular benefit with increased adverse events. [8]
Action: Combination no longer recommended as routine practice. If used, monitor CK and LFTs closely [8].
Isoniazid Major
Mechanism: Isoniazid is a structural analog of nicotinamide that inhibits niacin synthesis from tryptophan by depleting pyridoxal phosphate. [3]
Effect: Pellagra: dermatitis, diarrhea, dementia in patients on prolonged isoniazid without pyridoxine. [3]
Action: Always co-prescribe pyridoxine (25–50 mg/day) with isoniazid. Monitor for pellagra symptoms [3].
Anticoagulants (warfarin) Moderate
Mechanism: High-dose nicotinic acid may potentiate anticoagulant effect. [4]
Effect: Modest prolongation of PT/INR. [4]
Action: Monitor INR more frequently when initiating or adjusting nicotinic acid dose [4].
Diabetes medications Moderate
Mechanism: Nicotinic acid at pharmacological doses impairs glucose tolerance through increased hepatic glucose output and decreased insulin sensitivity. [4]
Effect: Worsened glycemic control in diabetic patients. HbA1c may increase by 0.3–0.5%. [4]
Action: Monitor blood glucose closely. Adjust diabetes medications as needed [4].
Supplement synergies
Riboflavin (B2) · 1.1–1.3 mg/day
FAD (from riboflavin) is required by kynurenine mono-oxygenase in the tryptophan-to-niacin synthesis pathway [1].
FAD (from riboflavin) is required by kynurenine mono-oxygenase in the tryptophan-to-niacin synthesis pathway [1].
Pyridoxine (B6) · 1.3–2.0 mg/day
Pyridoxal phosphate is essential for the tryptophan-to-niacin pathway. B6 deficiency impairs endogenous niacin synthesis [1].
Pyridoxal phosphate is essential for the tryptophan-to-niacin pathway. B6 deficiency impairs endogenous niacin synthesis [1].
Chromium · 200–400 µg/day chromium
Niacin-bound chromium (chromium polynicotinate) may improve insulin sensitivity synergistically with both nutrients [2].
Niacin-bound chromium (chromium polynicotinate) may improve insulin sensitivity synergistically with both nutrients [2].
7 Regulatory
United States (FDA): Classified as a dietary supplement (nicotinamide, nicotinic acid) and prescription drug (extended-release niacin for dyslipidemia, e.g., Niaspan). Mandatory fortification of enriched grains. UL 35 mg/day for supplemental nicotinic acid [1].
European Union (EFSA): Authorized health claims for energy metabolism, nervous system function, psychological function, mucous membranes, and skin [9]. UL: 10 mg/day for nicotinic acid (non-flush threshold); 900 mg/day for nicotinamide [1].
Japan (MHLW): Eligible for Foods with Function Claims. Recommended intake: 15 mg NE/day for adult males. Extended-release niacin not commonly prescribed.
South Korea (MFDS): Registered health functional food ingredient. Approved claims: energy metabolism and skin health.
8 US supplement products
2,968
on-market products containing Niacin (NIH DSLD)
Brands carrying Niacin (687)
Click a brand to see its Niacin products.
9 Frequently paired with
10 Cite this page
Vancouver: Pkhakadze G. Niacin — safety profile [Internet]. Tbilisi: PHIG; 2026 [cited 2026 Aug 15]. Available from: https://supplement.ge/ingredients/niacin/
APA 7th: Pkhakadze, G. (2026). Niacin — Safety profile. Public Health Institute of Georgia. https://supplement.ge/ingredients/niacin/
📋 Editorial information
Author: Prof. G. Pkhakadze, MD, MPH, PhD
Institution: Public Health Institute of Georgia (PHIG)
Affiliation: David Tvildiani Medical University (DTMU)
First published: January 2026
Last reviewed: 2026-05-29
Next review: February 2027
References: 9 cited sources
COI: SupplementIndex receives no funding from supplement manufacturers. All content independently authored by PHIG.
Process: Systematic literature review
📄 License & reuse
Published under Creative Commons Attribution 4.0 International (CC BY 4.0). You may share and adapt for any purpose with attribution.
Pkhakadze G. "Niacin — Safety Profile." SupplementIndex, PHIG, 2026. https://supplement.ge/ingredients/niacin/ CC BY 4.0.
GP
Prof. G. Pkhakadze, MD, MPH, PhD
Professor of Public Health · Head of Department, DTMU
Editor-in-Chief, Georgian Medical Journal (ISSN 3088-4322)
Chair, Public Health Institute of Georgia · UEMS Public Health Section
Educational and public health purposes. CC BY 4.0. Consult your healthcare provider before starting any supplement. Corrections: info@accreditation.ge. Publisher: PHIG