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Head-to-head evidence comparison — which supplement is right for you?
Cysteamine (topical) vs Glycolic Acid: Glycolic Acid has the stronger overall evidence (6 vs 6/10); they're alternatives for even skin tone — the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Glycolic Acid wins 1 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Too few graded studies
Top outcomes
Verdict
Too few graded studies
Top outcomes
Shared outcomes (1)
Outcomes where both Cysteamine (topical) and Glycolic Acid have evidence — compare verdict strength side-by-side.
Topical cosmetic. Cysteamine 5% cream is typically applied once daily to areas of melasma as a short-contact treatment (left on for ~15 minutes, then washed off) to limit odor and irritation, with daily sunscreen. There is no oral or systemic use in this context. This library does not provide an ingestion protocol.
Any time of day
Cysteamine 5% cream (short-contact application)
Topical cosmetic only. Leave-on glycolic acid is used at roughly 5-15% in lotions/serums (often at low pH), applied to clean skin a few nights per week and building as tolerated; professional peels (20-70%) are applied in-office at intervals. There is no oral, injectable, or systemic dose — it is not ingested. Pair with daily sunscreen. This library does not provide an ingestion protocol.
Evening
Leave-on lotion or serum (≈5-15% glycolic acid)
Throughout
8-16 weeks
Throughout
Throughout
Throughout
8-12 weeks
8-16 weeks
First weeks
Evaluation of the efficacy of cysteamine 5% cream in the treatment of epidermal melasma: a randomized double-blind placebo-controlled trial.
Br J Dermatol (2015) · Rct · n=50
First double-blind placebo-controlled RCT of cysteamine 5% cream for epidermal melasma (n=50), nightly for 4 months
Efficacy of cysteamine cream in the treatment of epidermal melasma, evaluating by Dermacatch as a new measurement method: a randomized double blind placebo controlled study.
J Dermatolog Treat (2018) · Rct · n=40
Second double-blind placebo-controlled RCT (n=40), nightly cysteamine 5% for 4 months, with Dermacatch and Mexameter colorimetry
A comparative study of topical 5% cysteamine versus 4% hydroquinone in the treatment of facial melasma in women.
Int J Dermatol (2020) · Rct · n=40
Multicenter evaluator-blinded head-to-head of cysteamine 5% vs hydroquinone 4% (n=40), nightly for 120 days with sunscreen
A double-blind randomized clinical trial on the effectiveness of a daily glycolic acid 5% formulation in the treatment of photoaging.
Dermatol Surg (1998) · Rct · n=75
75 volunteers applied 5% unneutralized glycolic acid cream or placebo to face and neck daily for 3 months (double-blind, randomized, placebo-controlled)
Clinical improvement of photoaged skin with 50% glycolic acid. A double-blind vehicle-controlled study.
Dermatol Surg (1996) · Rct · n=41
41 volunteers received a 50% glycolic acid peel vs vehicle weekly for 4 weeks (in-office peel strength)
Mode of action of glycolic acid on human stratum corneum: ultrastructural and functional evaluation of the epidermal barrier.
Arch Dermatol Res (1997) · Open label
Electron-microscopy study of human skin after 3 weeks of 4% glycolic acid twice daily
Glycolic Acid has a higher evidence score (6/10 vs 6/10) and wins in 1 of 3 categories.
For even skin tone, Cysteamine (topical) has a higher relevance score (70 vs 60).
No documented interaction was found in the data searched. This does not establish that this exact combination is safe.
The depigmenter playbook (hydroquinone, azelaic, tranexamic, vitamin C) with sunscreen as the spine.
AM/PM order, what to combine vs separate, and why sunscreen always comes first.
The proven core (sunscreen, retinoids, vitamin C) vs the viral hype tier — honestly tiered.
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.