Niacinamide
Supplement
vitamin B3 form
skin & hairgeneral nutrition
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Nad for 400+ enzymes · limited human evidence for skin
When to take
No timing rule on the sheet
Take with
No food needed for flushing — nicotinamide does not flush
Pros & cons
Pros
- Does not cause the flush nicotinic acid causes
- Almost completely absorbed, even at 3–4 g doses
- RDA is small — 16 mg ne men, 14 mg ne women
Cons
- UL 35 mg/day covers both supplemental niacin forms
- 3,000 mg/day: nausea, vomiting, liver-toxicity signs
- SG caps nicotinamide at 450 mg a day in supplements
Sources
- NIH ODS — Niacin (Health Professional), updated November 18, 2022 — Introduction (read via archive.org capture, see verify_notes) · read 2026-08-27
what it says
“Niacin is the generic name for nicotinic acid …, nicotinamide (niacinamide or pyridine-3-carboxamide), and related derivatives … More than 400 enzymes require NAD to catalyze reactions in the body, which is more than for any other vitamin-derived coenzyme”
- NIH ODS — Niacin (Health Professional) — Introduction, absorption · read 2026-08-27
what it says
“Even when taken in very high doses of 3–4 g, niacin is almost completely absorbed.”
- NIH ODS — Niacin (Health Professional) — Sources of Niacin, dietary supplements · read 2026-08-27
what it says
“Nicotinic acid in supplemental amounts beyond nutritional needs can cause skin flushing … Nicotinamide does not produce skin flushing because of its slightly different chemical structure”
- NIH ODS — Niacin (Health Professional) — Table 1 RDAs and the DV note · read 2026-08-27
what it says
“Table 1: Recommended Dietary Allowances (RDAs) for Niacin … 19+ years 16 mg NE 14 mg NE … The DV for niacin is 16 mg for adults and children age 4 years and older”
- NIH ODS — Niacin (Health Professional) — Health Risks from Excessive Niacin; Table 3 ULs · read 2026-08-27
what it says
“The FNB has established ULs for niacin that apply only to supplemental niacin … These ULs are based on the levels associated with skin flushing … applies to both forms of supplemental niacin … 19+ years 35 mg”
- NIH ODS — Niacin (Health Professional) — Health Risks, nicotinamide · read 2026-08-27
what it says
“Nicotinamide does not cause skin flushing and has fewer adverse effects than nicotinic acid … Nausea, vomiting, and signs of liver toxicity can occur with nicotinamide intakes of 3,000 mg/day”
- NIH ODS — Niacin (Health Professional) — Health Risks, hemodialysis studies · read 2026-08-27
what it says
“In several small studies of participants undergoing hemodialysis, the most common adverse effects from 500–1,500 mg/day nicotinamide supplementation for several months were diarrhea and thrombocytopenia (low platelet count)”
- NIH ODS — Niacin (Health Professional) — Niacin Deficiency, WHO pellagra regimen · read 2026-08-27
what it says
“The World Health Organization recommends treating pellagra with 300 mg/day nicotinamide in divided doses for 3–4 weeks along with a B-complex or yeast product to treat likely deficiencies in other B vitamins”
- NIH ODS — Niacin (Health Professional) — Interactions: isoniazid and pyrazinamide · read 2026-08-27
what it says
“Isoniazid and pyrazinamide …, used to treat tuberculosis, are structural analogs of niacin and interrupt the production of niacin from tryptophan … isoniazid can interfere with niacin's conversion to NAD”
- NIH ODS — Niacin (Health Professional) — Interactions: antidiabetes medications · read 2026-08-27
what it says
“Large doses of nicotinic acid can raise blood glucose levels by causing or aggravating insulin resistance … nicotinic acid doses of 1.5 g/day or more are most likely to increase blood glucose levels”
- Mainville L, Smilga AS, Fortin PR — Effect of Nicotinamide in Skin Cancer and Actinic Keratoses Chemoprophylaxis, and Adverse Effects Related to Nicotinamide: A Systematic Review and Meta-Analysis, J Cutan Med Surg 2022 · read 2026-08-27
what it says
“We screened 4730 citations and found 29 trials (3039 patients) meeting inclusion criteria … Nicotinamide was associated with … increased risk of digestive AEs … (GRADE: weak recommendation; moderate-quality evidence)”
- Liu H et al. — Evidence-based topical treatments (azelaic acid, salicylic acid, nicotinamide, sulfur, zinc, and fruit acid) for acne: an abridged version of a Cochrane systematic review, J Evid Based Med 2020 · read 2026-08-27
what it says
“There were no studies measured PGA when evaluating nicotinamide … Moderate-quality evidence was available for azelaic acid and low- to very-low-quality evidence for other topical treatments”
- HSA Singapore — Guidelines on Prohibited and Restricted Ingredients in Health Supplements and Traditional Medicines, GL-CHPB-1-012 Rev. No. 001 (October 2025), Annex A rows 75–76 · read 2026-08-27
what it says
“75. Nicotinamide Restricted use in HS and TM Maximum Daily Dose When for oral use by general adult population, the maximum recommended daily dose should not provide more than 450mg”
- HSA Singapore — Health Supplements Guidelines GL-CHPB-3-001 Rev. No. 020 (January 2026), clause 4.8 and Table 4 Vitamins Limits · read 2026-08-27
what it says
“4.8 HS for use by the general adult population should not contain vitamins and minerals exceeding the stipulated limits stated in Tables 4 and 5 … Table 4: Vitamins Limits … Nicotinic acid 15mg Nicotinamide 450mg”
- iHerb Singapore — Vitamin B3 (Niacin) category page, default listing order · read 2026-08-27
what it says
“Vitamin B3 (Niacin) … 1 - 48 of 274 results … California Gold Nutrition, NMN, 175 mg … NOW Foods, Niacinamide, 500 mg … ProHealth Longevity, NMN Pro™ 1000 … Life Extension, Vitamin B3 Niacin, 500 mg … Thorne, ResveraCel®”
Updated 2026-08-30. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.