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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 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
Topical use, typically ~2-5% tranexamic acid in a serum applied to areas of melasma once or twice daily, alongside daily sunscreen. There is no oral or systemic dose in this cosmetic context — the ingested medication is a separate prescription use with clotting-risk considerations. This library does not provide an ingestion protocol.
any
Leave-on topical serum (≈2-5% tranexamic acid)
Throughout
Ongoing (years)
Ongoing
Throughout
Throughout
8-12 weeks
Throughout
Throughout
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
Topical tranexamic acid as a promising treatment for melasma.
J Res Med Sci (2014) · Rct · n=50
Double-blind 12-week split-face RCT in 50 women: 3% topical TXA on one side vs 3% hydroquinone + 0.01% dexamethasone on the other, twice daily
The effectiveness and safety of 3% tranexamic acid cream vs. 4% hydroquinone cream for mixed-type melasma in skin of color: a double-blind, split-face, randomized controlled trial.
Acta Dermatovenerol Alp Pannonica Adriat (2024) · Rct · n=20
Double-blind 8-week split-face RCT in 20 skin-of-color subjects comparing 3% topical TXA cream vs 4% hydroquinone cream
Tranexamic acid as a therapeutic option for melasma management: meta-analysis and systematic review of randomized controlled trials.
J Dermatolog Treat (2024) · Meta analysis
Meta-analysis of 22 RCTs (1280 patients) of TXA delivered orally, topically, or by injection for melasma
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 Sunscreen (SPF) and Tranexamic Acid (topical) have been documented in our database. However, always consult a healthcare provider before combining supplements.