Tranexamic acid, often shortened to TXA, is used in serums for stubborn brown patches and uneven tone. It is also given as tablets and injections in medical care. On skin, studies at 2% to 5% found brown patches faded over 8 to 12 weeks, though one controlled trial found no difference from the plain base.
- Helps with
- brown patches, dark spots, uneven skin tone, redness
- Evidence
- Limited. Small topical trials with mixed results; the strongest data come from tablets and injections, which are medical uses.
- Typical strength
- 2–5% in the topical studies cited here
- Works well with
- daily sunscreen, niacinamide
What does tranexamic acid do for skin?
Tranexamic acid is for brown that will not shift: the patchy, shadow-like marks across the cheeks or upper lip that deepen every summer, and the uneven tone that concealer never quite hides. In serums it is used to lighten those patches gradually.
In a 12-week study, 23 people with mild patches applied a 2% tranexamic acid formula to the whole face. Scores for the patches improved in 22 of the 23, skin measured lighter and less red, and skin samples from 10 participants showed less pigment in the outer layer.
How does tranexamic acid work?
Brown patches are not only about pigment cells; the cells and tiny blood vessels around them send signals that keep pigment production switched on. The 2016 study found tranexamic acid turned down one of those signals, and its authors concluded that “suppression of ET-1 could be one of the mechanisms of action of TA on melasma.” In plain terms, it seems to quiet the background messages that tell skin to keep making color. The same samples showed a trend toward fewer small blood vessels.
Does tranexamic acid work better than other brightening ingredients?
The evidence is mixed. In a 12-week split-face trial, 23 women used 5% tranexamic acid on one side and the same gel without it on the other, plus sunscreen. Pigment dropped in 18 of them, but the tranexamic acid side did no better than the plain side. In another split-face study of 15 women having light treatments, the tranexamic acid side kept improving for 12 weeks after the last session, while the plain side did not.
A 2024 review of 22 trials with 1,280 patients found the clearest results for tablets, then injections, with creams and serums showing the smallest effect. Tablets and injections are medical treatments prescribed by doctors; serums are a gentler, slower option.
How long until you notice a difference?
The topical studies ran for 8 to 12 weeks. Expect changes over 2 to 3 months, not days.
How do you use tranexamic acid?
Once or twice a day after cleansing, with sunscreen every morning; the 5% trial added sunscreen each morning for that reason. It is often formulated with niacinamide, which works on a different step of pigment. For a routine built around dark marks, see a skincare routine for dark circles.
Who should be careful with tranexamic acid?
The topical studies above reported no serious side effects. Across tablets, injections and creams, the 2024 review listed stomach upset, skin irritation and menstrual changes among side effects; tablets and injections are prescribed and monitored by doctors, while a serum should simply be stopped if it irritates.
- Kim SJ, et al. Efficacy and possible mechanisms of topical tranexamic acid in melasma. Clin Exp Dermatol. 2016;41(5):480-5.
- Kanechorn Na Ayuthaya P, et al. Topical 5% tranexamic acid for the treatment of melasma in Asians: a double-blind randomized controlled clinical trial. J Cosmet Laser Ther. 2012;14(3):150-4.
- Chung JY, et al. Topical tranexamic acid as an adjuvant treatment in melasma: side-by-side comparison clinical study. J Dermatolog Treat. 2016;27(4):373-7.
- Calacattawi R, et al. Tranexamic acid as a therapeutic option for melasma management: meta-analysis and systematic review of randomized controlled trials. J Dermatolog Treat. 2024;35(1):2361106.
Editorial content, not medical advice.