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Head-to-head evidence comparison — which supplement is right for you?
Sunscreen (SPF) wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Mostly mechanism / observational
Top outcomes
Verdict
Mostly mechanism / observational
Top outcomes
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
Cysteamine 5% cream (short-contact application)
Topical OTC. Apply a broad-spectrum SPF 30+ sunscreen daily to sun-exposed skin as the last step of a morning routine, using an adequate amount (about 2 mg/cm² — roughly a nickel-sized dollop for the face, a shot-glass for the body) and reapply every ~2 hours of sun exposure and after swimming/sweating. Mineral (zinc oxide / titanium dioxide) filters are preferred if you're concerned about systemic absorption. There is no oral or systemic dose — it is not ingested. This library does not provide an ingestion protocol.
morning
Broad-spectrum SPF 30+, applied daily; mineral (zinc oxide/titanium dioxide) if concerned about absorption
Throughout
8-16 weeks
Throughout
Throughout
Throughout
Ongoing (years)
Ongoing
Throughout
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
Sunscreen and prevention of skin aging: a randomized trial.
Ann Intern Med (2013) · Rct · n=903
Randomized community trial (n=903): the daily sunscreen group showed no detectable increase in photoaging (skin microtopography) after 4.5 years
Molecular mechanisms of photoaging and its prevention by retinoic acid: ultraviolet irradiation induces MAP kinase signal transduction cascades that induce Ap-1-regulated matrix metalloproteinases that degrade human skin in vivo.
J Investig Dermatol Symp Proc (1998) · Review
Mechanistic model: UV activates MAP-kinase pathways and AP-1, which upregulate matrix metalloproteinases (MMPs)
Daily Use of a Facial Broad Spectrum Sunscreen Over One-Year Significantly Improves Clinical Evaluation of Photoaging.
Dermatol Surg (2016) · Open label · n=32
Single-arm prospective study (n=32): broad-spectrum SPF 30 applied daily to the face for 52 weeks
Sunscreen (SPF) has a higher evidence score (9/10 vs 6/10) and wins in 2 of 3 categories.
For even skin tone, Sunscreen (SPF) has a higher relevance score (75 vs 70).
No known interactions between Cysteamine (topical) and Sunscreen (SPF) have been documented in our database. However, always consult a healthcare provider before combining supplements.