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Head-to-head evidence comparison — which supplement is right for you?
Glutathione and Nicotinamide are closely matched across evidence, studies, and safety.
Verdict
Mostly mechanism / observational
Top outcomes
Verdict
Probably helps
2 of 3 studies with measurable effects showed benefit.
Top outcomes
250-1000mg/day oral reduced L-glutathione (skin-lightening trials often used ~500mg); liposomal/sublingual forms aim to improve absorption
between-meals
Liposomal or sublingual glutathione (for absorption)
500mg twice daily
Morning and evening with meals
Niacinamide tablets (500mg)
4-12 weeks
8-12 weeks
Throughout use
3-12 months
8 weeks
Days
First days
Randomized controlled trial of oral glutathione supplementation on body stores of glutathione.
European journal of nutrition (2015) · Rct · n=54
Increased glutathione in some body compartments over 6 months
Glutathione as a skin-lightening agent and in melasma: a systematic review.
International journal of dermatology (2025) · Systematic review
Skin-lightening and melasma improvement reported
The clinical effect of glutathione on skin color and other related skin conditions: A systematic review.
Journal of cosmetic dermatology (2019) · Systematic review
Reduced melanin/skin darkening in trials
A Phase 3 Randomized Trial of Nicotinamide for Skin-Cancer Chemoprevention.
The New England journal of medicine (2015) · Rct · n=386
ONTRAC: phase-3, double-blind RCT randomizing 386 patients with ≥2 prior non-melanoma skin cancers to 500 mg nicotinamide twice daily or placebo for 12 months
Skin Cancer Prevention and Antiaging: Role of Nicotinamide.
International journal of molecular sciences (2026) · Review
Review of the biological rationale and clinical evidence for nicotinamide and NAD+ precursors in photoaging and cutaneous carcinogenesis
Topical nicotinamide compared with clindamycin gel in the treatment of inflammatory acne vulgaris.
International journal of dermatology (1995) · Rct · n=76
Double-blind RCT of 76 patients randomized to 4% nicotinamide gel or 1% clindamycin gel twice daily for 8 weeks for moderate inflammatory acne
The ONTRAC RCT used 500 mg twice daily (1000 mg/day total) and reduced new non-melanoma skin cancers by 23%. Effect requires continuous use; it disappeared after discontinuation. Curve is indicative — only the 1000 mg/day regimen is directly RCT-supported.
AI-estimated from published studies. Interpret as directional guidance.
Both Glutathione and Nicotinamide are closely matched — the best choice depends on your specific health goals.
For improve skin health, Nicotinamide has a higher relevance score (68 vs 62).
No known interactions between Glutathione and Nicotinamide have been documented in our database. However, always consult a healthcare provider before combining supplements.