Niacin Dosage Guide: Protocols, Calculator & Safety
Everything you need to know about Niacin dosing — protocols, safety, and where to buy.
Dosage Calculator
Calculate exact dosing for Niacin.
Dosing Protocols
Beginner — routine dietary adequacy and basic skin/metabolic support. Most adults eating a varied Western diet with fortified grains and adequate protein meet the RDA (16 mg NE/day men, 14 mg NE/day women) without supplementation. A basic multivitamin containing 20-50 mg niacinamide covers any gaps. Food sources: turkey breast, chicken breast, tuna, salmon, peanuts, brown rice, fortified cereals, beef liver. For general skin support, topical niacinamide 2-5% in a moisturizer or serum applied daily is well-tolerated and has modest evidence for barrier function, hyperpigmentation, and mild photoaging. For frequent actinic keratoses or low-grade skin cancer history without meeting full ONTRAC criteria, nicotinamide 500 mg once or twice daily is low-risk. No pharmacologic nicotinic acid at beginner tier.
Intermediate — targeted clinical and NAD+ precursor supplementation. For non-melanoma skin cancer chemoprevention in patients with ≥2 prior BCC or SCC in the preceding 5 years, ONTRAC-style nicotinamide 500 mg twice daily indefinitely under dermatology supervision is evidence-based at 23% cancer reduction (PMID 26488693). For topical skincare, niacinamide 4-10% formulations for hyperpigmentation, acne, rosacea erythema, and skin barrier support have robust cosmeceutical evidence. For NAD+ precursor supplementation in aging and metabolic health contexts, nicotinamide riboside 300-1000 mg/day (Tru Niagen or equivalent) or NMN at equivalent doses (see the NMN entry) reliably raises blood NAD+ 40-90% over 1-4 weeks (PMID 29599478, 29985198); biomarker and early clinical trial data support this for healthy aging interventions, though definitive long-term benefit remains unproven. For familial hypertriglyceridemia refractory to fibrates or Lp(a)-driven residual cardiovascular risk despite statin, pharmacologic nicotinic acid 1-2 g/day (starting 500 mg/day and titrating up weekly, always taken with food, always with aspirin 325 mg 30 minutes prior for the first weeks until tachyphylaxis develops, with baseline and periodic LFTs and glycemic monitoring) is specialty-directed therapy with modest expected Lp(a) and triglyceride reduction. For Hartnup disease, nicotinamide 100-300 mg/day produces clinical resolution of pellagra-like symptoms. For hyperhomocysteinemia with low B3 and B6, combined B-complex repletion addresses both.
Advanced — high-dose specialist niacin protocols and investigational applications. For Friedreich ataxia, nicotinamide 2-8 g/day in open-label trials has shown frataxin-raising activity and preliminary symptomatic effects; this is investigational and requires neurology/metabolic specialist supervision. For ALS with NRPT (nicotinamide riboside + pterostilbene), the commercial combination or research protocols deliver NR 600-2000 mg/day plus pterostilbene 100-500 mg/day; preliminary data show reduced disease progression measures. For Alzheimer disease, experimental protocols of nicotinamide 1500-3000 mg/day or nicotinamide riboside 1000 mg/day have shown biomarker improvements in small trials; remain investigational. For advanced pharmacologic nicotinic acid lipid therapy, maintenance doses up to 3 g/day are used in familial combined hyperlipidemia, Lp(a)-driven residual CV risk, or statin-intolerant patients under lipidologist supervision, with strict LFT and glycemic monitoring. For refractory rosacea, bullous pemphigoid, or other dermatological autoimmune conditions, nicotinamide 1500-3000 mg/day in combination with tetracycline-class antibiotics has a modest evidence base under dermatology supervision. For anti-aging NAD+ stacking, combined NR + resveratrol + sirtuin-activator regimens with various commercial formulations exist but lack robust outcome data; doses of NR 1000 mg/day plus pterostilbene 250 mg/day plus resveratrol 500 mg/day are representative. For pharmacological niacin in high-dose oncology adjunct research (breast cancer chemoprevention studies, various investigational contexts), protocols remain research-stage. All high-dose specialist protocols require physician supervision, specific indication, laboratory monitoring, and attention to form selection (nicotinic acid vs nicotinamide vs NR vs NMN).
Commonly Stacked With
Niacin stacks with several other compounds in biologically meaningful ways. NAD+ precursor stacking: NR + NMN are pharmacologically similar (both merge at the NMN step of the salvage pathway) and combining them produces no synergistic effect over equivalent single-compound dosing in preclinical work; most authorities recommend choosing one rather than both. Combining NR or NMN with sirtuin activators (resveratrol, pterostilbene) has theoretical appeal because the former raises NAD+ substrate availability and the latter activates sirtuin enzymes — the NRPT product (nicotinamide riboside + pterostilbene, commercial name Basis by Elysium) embodies this approach with preliminary ALS and aging trials showing biomarker benefits. NAD+ + lipoic acid: see the Alpha-Lipoic Acid entry for the parallel cofactor roles in pyruvate and α-ketoglutarate dehydrogenase complexes; co-supplementation is reasonable for mitochondrial optimization. NAD+ + CoQ10: NAD+ precursors and CoQ10 target sequential electron transport chain components (NADH → complex I → CoQ → complex III → cytochrome c → complex IV → O2), so co-supplementation addresses complementary bioenergetic nodes. Nicotinic acid + statin: standard cardiovascular combination for patients with low HDL and residual risk despite statin monotherapy — see AIM-HIGH and HPS2-THRIVE cautions (PMID 22085343, 25014686). Nicotinic acid + aspirin: 325 mg aspirin 30 minutes before niacin dosing blocks flushing via prostaglandin D2 inhibition. Nicotinic acid + omega-3: additive triglyceride lowering; see the Omega-3 fatty acids entry. Nicotinic acid + bile acid sequestrant: additive LDL lowering with separate dosing (4-6 hours apart). Nicotinamide + sun protection: the ONTRAC rationale assumes continued rigorous sun protection; nicotinamide complements rather than replaces sunscreen. Nicotinamide for skin + topical retinoids: commonly combined in dermatology; generally well-tolerated. Nicotinamide + vitamin D: immune and dermatological co-support; see the Vitamin D3 entry where applicable. B-complex co-administration rationale: niacin sits alongside B1 (thiamine), B2 (riboflavin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), and B12 (cobalamin) in overlapping metabolic pathways, and multi-deficiency is more common than isolated deficiency in alcoholism, malabsorption, and refeeding contexts. Niacin + tryptophan: because endogenous niacin can be made from tryptophan via the kynurenine pathway, adequate protein intake reduces niacin requirement; this is relevant historically (pellagra in corn-dependent populations with tryptophan-poor protein) but not a clinical supplement combination. Niacin + pyridoxine (B6): B6 is required at multiple steps of the kynurenine pathway, so B6 deficiency can precipitate pellagra in patients with marginal niacin intake; see the Vitamin B6 entry. Niacin + iron: IDO/TDO at the first steps of the kynurenine pathway are iron-dependent; iron deficiency can impair endogenous niacin synthesis, see the Iron entry. Nicotinic acid + metformin: metformin and nicotinic acid have partially opposing effects on glycemia (metformin reduces insulin resistance, nicotinic acid at gram doses worsens it); combining requires careful glycemic monitoring — see the Metformin entry. The cleanest stacking summary: NAD+ precursors (NR/NMN) pair well with sirtuin activators (resveratrol, pterostilbene) and mitochondrial cofactors (lipoic acid, CoQ10) for aging-biology stacking; nicotinic acid pharmacotherapy pairs with aspirin for flushing mitigation and with statins for cardiovascular risk reduction (with cautions); nicotinamide 500 mg BID stands alone as chemoprevention with continued sun protection. See the NMN entry for the sister NAD+ precursor, Alpha-Lipoic Acid and CoQ10 for mitochondrial co-supports, Thiamine for the companion energy-metabolism cofactor, Vitamin B6 and Iron for the tryptophan-to-niacin pathway dependencies, Folate and Vitamin B12 for the broader B-complex, Omega-3 fatty acids for cardiovascular co-support, Metformin for metabolic aging context, Vitamin D3 for dermatological co-support, and Choline for hepatic methylation partnership.
Side Effects & Safety
Contraindications
**Absolute contraindications** to pharmacologic nicotinic acid include known hypersensitivity to niacin or any formulation component, active hepatic disease or unexplained persistent transaminase elevation, active peptic ulcer disease, and arterial bleeding. **Relative contraindications** to pharmacologic nicotinic acid: diabetes mellitus (requires intensive glycemic monitoring and may preclude use if glycemic control is marginal); gout or hyperuricemia (may precipitate gout flares); unstable angina or recent MI (short-term hemodynamic concerns in severely compromised patients); concomitant alcohol use (additive hepatotoxicity and flushing); concomitant statin (modest increased myopathy risk, generally acceptable with monitoring); chronic kidney disease stage 4-5 (altered pharmacokinetics, more frequent monitoring); pregnancy (pharmacologic doses not routinely recommended); age under 16 (pharmacologic dyslipidemia indications rare at this age). For **nicotinamide** at typical supplement and therapeutic doses, contraindications are limited to known hypersensitivity; pharmacologic nicotinamide doses above 3 g/day may produce hepatotoxicity and require monitoring. For **nicotinamide riboside**, contraindications include known hypersensitivity; NR''s safety profile is well-established up to 1-2 g/day in short-to-medium term use. For **topical niacinamide**, contraindications are limited to known hypersensitivity (rare). Pregnancy: nicotinamide at RDA to ONTRAC-style doses has no signal of teratogenicity; pharmacologic nicotinic acid for lipid indications is not routinely recommended in pregnancy and should only be used if compelling indication. Breastfeeding: RDA-range niacin is safe and essential; higher therapeutic doses should be physician-directed. Pediatric: RDA-range niacin is essential; pharmacologic doses for specific indications (Hartnup, dyslipidemia) under specialist supervision. The principal practical caution is that pharmacologic nicotinic acid has a moderately narrow therapeutic window with hepatotoxicity, glycemic worsening, and hyperuricemia as the key adverse effects, while nicotinamide and nicotinamide riboside are substantially more forgiving for most indications.
Additional Notes
The adult RDA for niacin is 16 mg NE/day for men, 14 mg NE/day for women, 18 mg NE/day in pregnancy, 17 mg NE/day in lactation. Niacin Equivalents (NE) account for endogenous tryptophan-to-niacin conversion at approximately 60 mg tryptophan → 1 mg niacin. The tolerable upper intake level is 35 mg/day for nicotinic acid (primarily based on flushing), with no established UL for nicotinamide because of its much wider therapeutic window. Food sources: turkey breast, chicken breast, tuna, salmon, peanuts, brown rice, whole wheat, fortified cereals, beef liver, peanut butter, portobello mushrooms, green peas, lentils. Corn-dependent diets without nixtamalization (lime treatment) produce poor niacin bioavailability — the historical cause of pellagra in the American South and southern Europe. Oral absorption is essentially complete for all forms at physiologic doses; pharmacologic doses (grams per day of nicotinic acid) show saturable hepatic first-pass metabolism, producing nonlinear pharmacokinetics. Plasma half-life is short (30-60 minutes for nicotinic acid, 4 hours for nicotinamide, variable for NR depending on measurement approach). Urinary excretion of N-methylnicotinamide and 2-pyridone metabolites serves as status marker. Whole-blood NAD+ measurement is increasingly used to assess NAD+ precursor supplement efficacy. For pharmacologic nicotinic acid, start low (250-500 mg/day with evening meal plus pre-dose aspirin 325 mg) and titrate weekly by 250-500 mg to target 1-2 g/day divided bid or taken qhs. Extended-release Niaspan is typically dosed qhs and titrated from 500 mg to 1-2 g over 4-8 weeks. Immediate-release nicotinic acid has shorter flushing bursts but more frequent dosing; extended-release has longer flushing but more hepatotoxicity risk. Nicotinamide for ONTRAC protocol: 500 mg twice daily, morning and evening, indefinitely. Topical niacinamide: 2-10% in appropriate vehicle, once or twice daily as tolerated. Nicotinamide riboside: 300-1000 mg/day, with or without food, usually morning dosing to avoid sleep disruption in sensitive individuals. NMN: see NMN entry. All forms: adequate B6 status supports endogenous niacin synthesis; iron status affects kynurenine pathway IDO/TDO enzymes.
Frequently Asked Questions
What is the recommended Niacin dosage?
Dosage for Niacin varies by protocol. Consult a qualified healthcare provider.
How often should I take Niacin?
Administration frequency depends on the specific protocol. Consult current research literature.
Does Niacin need to be cycled?
Cycling requirements depend on the protocol. Follow established research guidelines.
What are Niacin side effects?
The niacin side effect profile divides sharply by form. **Nicotinic acid at pharmacologic doses** (1-3 g/day) produces several well-characterized adverse effects that limit tolerability and define its narrow therapeutic window. **Flushing** is the hallmark adverse effect — warmth, erythema, and sometimes pruritus affecting the face, neck, and upper chest starting 15-30 minutes after dose and lasting 30-60 minutes. Mediated by GPR109A-triggered prostaglandin D2 release acting on DP1 cutaneous vasodilatory receptors, flushing is most severe with the first doses and diminishes over weeks of continued daily use (tachyphylaxis). Aspirin 325 mg 30 minutes before niacin blocks the prostaglandin synthesis step and substantially reduces flushing. Extended-release formulations (Niaspan) reduce peak nicotinic acid concentrations and produce less flushing than immediate-release. Slow dose titration (starting at 250-500 mg/day and increasing weekly by 250-500 mg to target 1.5-2 g/day) is standard practice. Avoiding hot showers, hot beverages, and alcohol within an hour of dosing reduces flushing severity. **Hepatotoxicity** is a serious dose-related adverse effect of nicotinic acid. Transaminase elevations occur in 3-10% of patients at gram-range doses, typically at 1-3 g/day with peak incidence several weeks into therapy. Extended-release and sustained-release formulations have been reported to cause more severe hepatotoxicity than immediate-release in some case series, possibly through first-pass hepatic saturation. Progressive liver injury, cholestatic hepatitis, and rarely fulminant hepatic failure have been reported. Monitoring: baseline LFTs, repeat at 6-12 weeks during titration, then every 6 months during maintenance. Discontinue or reduce dose for AST/ALT elevation above 3x upper limit of normal. "No-flush niacin" (inositol hexanicotinate) has been associated with hepatotoxicity despite limited lipid-lowering effect — an unfavorable benefit-risk profile. **Glycemic worsening**. Nicotinic acid at pharmacologic doses increases fasting glucose and HbA1c in a subset of patients, particularly those with pre-diabetes or established diabetes. The effect is thought to involve rebound increases in free fatty acids and worsened insulin resistance. Glycemic monitoring is required when initiating nicotinic acid in diabetics or those with pre-diabetes. For patients on oral antidiabetic agents or insulin, dose adjustments may be needed. HPS2-THRIVE showed a significant excess of new-onset diabetes in the niacin arm (PMID 25014686). **Hyperuricemia and gout**. Nicotinic acid competes with uric acid for renal tubular secretion, producing hyperuricemia that can precipitate gout flares in susceptible patients. Caution in established gout. **Gastrointestinal effects** (nausea, dyspepsia, peptic ulcer exacerbation, diarrhea) are common at gram-range doses. Nicotinic acid should be taken with food. Patients with active peptic ulcer disease should avoid pharmacologic nicotinic acid. **Myopathy** risk with nicotinic acid plus statin was raised by the HPS2-THRIVE signal but is controversial; mainstream assessment is that niacin-statin combination produces a modest myopathy risk that is substantially smaller than with gemfibrozil-statin combinations. **Other nicotinic acid effects**: headache, fatigue, nasal congestion, blurred vision (macular edema rarely), amblyopia, acanthosis nigricans (reported with chronic high-dose use), hypotension (especially with antihypertensives), sensation of warmth, and rarely atrial arrhythmias. **Nicotinamide at typical doses** (up to 3 g/day) is remarkably free of the above effects. No flushing, no lipid effects, no glycemic worsening, no hyperuricemia. Rare hepatotoxicity has been reported at doses above 3 g/day. GI upset is mild and uncommon. Nicotinamide is therefore the preferred form when flushing or lipid effects are not desired — skin cancer prevention, dermatological indications, NAD+ precursor use. **Nicotinamide riboside (NR)** at doses up to 1-2 g/day has an excellent short-to-medium term safety profile in clinical trials (no hepatotoxicity, no glycemic effects, no flushing, minimal GI upset). Long-term safety data beyond 1-2 years is limited. **Drug interactions**. Statins with nicotinic acid: modest increased myopathy risk (see above). Oral antidiabetics: glycemic monitoring needed with pharmacologic nicotinic acid. Antihypertensives: additive hypotension with nicotinic acid. Alcohol: increases flushing severity. Bile acid sequestrants: separate dosing by 4-6 hours. Warfarin: occasional case reports of INR interaction, monitor. Isoniazid: INH competes with pyridoxal-dependent kynurenine pathway and can precipitate pellagra; repletion with B6 and sometimes B3 is appropriate in INH therapy. **Pregnancy and lactation**. Nicotinamide at RDA range is safe and required; pharmacologic nicotinamide doses for specific indications should be physician-directed. Nicotinic acid pharmacologic doses are not routinely recommended in pregnancy. ONTRAC-style nicotinamide at 500 mg BID for skin cancer prevention has not been studied in pregnancy. **Pediatric use**. RDA-range niacin is essential. Pharmacologic doses are occasionally used in pediatric dyslipidemia (rare) or Hartnup disease management under specialist supervision. The cleanest safety summary: pharmacologic nicotinic acid has a moderately narrow therapeutic window with flushing, hepatotoxicity, glycemic worsening, and hyperuricemia as the principal concerns; nicotinamide at typical doses is much more forgiving and appropriate for chemoprevention and dermatological uses; nicotinamide riboside has a good short-medium term safety profile but limited long-term data.
Where can I buy Niacin?
Visit our vendor directory to find trusted sources for Niacin.
Free 2026 Peptide Cheat Sheet — 50 pages, PDF
Dosing, reconstitution, stacks, half-lives, and vendor trust tiers. The reference we wish we had on day one.
