Tranexamic Acid

Measured on: melasma pigment score (MASI/mMASI) and melanin index; no onset has been established for topical tranexamic acid on its own.

Every timing statement for this ingredient traces to a review or to a trial with no inert arm. The row's headline source pools oral, topical and intradermal TXA together, and its topical subgroup was not significantly different from comparators at either pooled timepoint (8 weeks SMD -0.05, 95% CI -1.08 to 0.97, P=0.92; 12 weeks SMD 0.66, 95% CI -0.10 to 1.42, P=0.09), with the authors asking for more research on the topical route. The one double-blind vehicle-controlled trial of topical TXA alone put 5% cream against its own vehicle on opposite halves of 23 faces for 12 weeks: MASI fell significantly on both sides, the difference between the sides was not significant, and the treated side was significantly more erythematous. A within-arm fall of roughly a quarter in an arm with no vehicle beside it dates sunscreen, season and regression to the mean as readily as it dates a drug. The 2026 review's 'early visible improvement by week 4-8' comes from the same uncontrolled and active-comparator material, so it cannot be promoted to a bucket either. Creams in this literature run 2-5%; the single 10% result comes from a split-face study in which both sides were microneedled first, which tests delivery rather than concentration. What is missing is specific: any vehicle-controlled trial of a leave-on TXA product reporting a visit at which pigment separated from vehicle.

PMID:38283017 (Indian Dermatol Online J 2024, meta-analysis of oral, topical and intradermal tranexamic acid in melasma; topical subgroup non-significant at 8 and 12 weeks). PMID:22506692 (Kanechorn Na Ayuthaya et al., J Cosmet Laser Ther 2012, 5% topical TXA vs its own vehicle, split-face, 23 women, 12 weeks, no significant difference between sides). PMID:32769524 (Dermatol Surg 2020, topical TXA with microneedling — a delivery study). PMID:41601401 (J Cosmet Dermatol 2026, narrative review). No vehicle-controlled trial of topical TXA alone reports a timepoint at which it separated from vehicle.