What is tranexamic acid, and why is it used for melasma?
Tranexamic acid is an antifibrinolytic: it slows the breakdown of blood clots. In the United States the tablets are licensed for heavy menstrual bleeding, and the injection for bleeding after tooth extraction in haemophilia. Reviews describe its use for melasma as off-label, and the US tablet labels do not mention melasma. Transamin is one of several brand names for tranexamic acid.
Melasma is a chronic pigment condition that sun, heat and hormones can trigger or worsen, and affected skin also shows more blood vessels and more mast cells. Tranexamic acid blocks plasmin, an enzyme that ultraviolet light raises in skin cells and that feeds a chain of prostaglandin signals switching pigment cells on, a pathway suggested by animal work. In a small uncontrolled study of tablets plus cream in 25 women, biopsies from eight showed fewer vessels and mast cells after treatment, and in cell studies the drug dampened vessel growth signals.
Do tranexamic acid tablets work for melasma?
On average, yes, in trials. A 2024 meta-analysis of 22 randomised trials with 1,280 patients found that tranexamic acid lowered melasma severity scores whether taken by mouth, applied or injected, with tablets showing the largest fall, although results differed a great deal between trials. A Singapore retrospective analysis of 561 patients who took tablets for a median of four months, with no comparison group, found that nearly 90% improved, mostly within two months, and about a quarter of those who improved later relapsed.
The limits matter. Trials mostly ran 8 to 12 weeks, methods differed widely, and long-term data are limited. Doses studied were mostly 250 to 500 mg twice a day. A network analysis of six trials estimated about 750 mg a day for 12 weeks as the optimal dose and called 500 mg a day acceptable for people who struggle to keep taking the tablets, while a small open-label randomised comparison of 500 mg and 1,000 mg a day reported comparable efficacy. No dose or length has been agreed, and a dose is for a prescriber to decide.
The 2026 international consensus, from a panel of ten experts whose paper declares industry ties, does not lead with the tablets. Daily sun protection is the mainstay and topical treatment is the first line. Oral agents are not recommended first for mild melasma, although they have a place in moderate to severe melasma. Oral tranexamic acid appears at the third line, recommended if it has not been used before or is still helping without significant adverse reactions, in people at low risk of clots. For mild melasma it is a later option.
Who should not take tranexamic acid tablets?
The concern is unwanted clots, in the legs, lungs, brain or the blood vessels of the eye. US prescribing information lists as contraindications a current clot, a past clot including a blocked vein or artery in the eye, a condition that raises clot risk such as a clotting disorder or certain heart valve or rhythm disease, combined hormonal contraception, and allergy to the drug. The label says the tablets are not indicated in pregnancy, calls for a lower dose in kidney impairment, and tells anyone with visual symptoms to stop and see an ophthalmologist. Hormone-containing pills, implants and hormone therapy are also named as melasma triggers, so some people with melasma are already using one of them.
The evidence on how often clots occur is reassuring but incomplete. A 2025 systematic review of randomised trials of oral tranexamic acid reported no clot events, and a 2025 record-based study of 682 matched pairs with melasma found similar rates of venous clots with and without tablets, although a retrospective study of that size cannot rule out an increase. Trial participants were selected, and the record-based study excluded anyone with a clotting disorder, hormone use, smoking or an earlier clot. In the Singapore series one woman developed a deep vein thrombosis and was later found to have inherited protein S deficiency. In a Danish national register study of women aged 15 to 49 with no earlier clot, women who filled prescriptions, at daily doses several times higher than in melasma and for a few days at a time, had about four times the rate of venous clots seen in non-use, from a low starting point. That figure cannot be read across directly to melasma treatment.
Screening therefore starts with a careful personal and family history, and some expert panels also ask for baseline clotting tests. In Malaysia tranexamic acid is a Group B poison under the Poisons Act 1952, which allows retail supply by a registered doctor to his or her own patient, or by a licensed pharmacist against a prescription. Supplying it by retail outside what the Act allows is an offence. Tranexamic acid inside a cosmetic notified under the Control of Drugs and Cosmetics Regulations 1984 is exempt. Tablets and "whitening" products bought online or outside a clinic skip the screening this drug needs, and the 2026 consensus found no place for intravenous glutathione in melasma, a subject covered in whitening drips and glutathione injections. Whether tranexamic acid suits anyone is a decision for a doctor who has taken the history and examined the skin.
Do tranexamic acid creams and injections work?
Both have been tested, with smaller and more varied evidence. Topical tranexamic acid, in creams and serums of about 2% to 5% applied twice daily for around 12 weeks, has performed about as well as hydroquinone in some small trials, with fewer side effects. One review found it the least effective route on its own, and an expert panel positions it as an option for people who have already tried other treatment.
Intradermal tranexamic acid means tiny injections of a dilute solution into the patch, given every two to four weeks for around three to six months in the studies reviewed. Reported side effects are pain, burning and redness at the injection site and, in some reports, a temporary pale patch. Pooled analyses disagree on the ranking: one places tablets first, one places injections and microneedling ahead of tablets, and a third found no added benefit from topical or injected use on top of standard treatment. A small Thai study followed five patients for 48 weeks after seven injection sessions: melasma returned in three of them, and by 48 weeks the improvement across the group was no longer statistically significant, although severity stayed below where it began.
Will melasma come back, and what has to stay in place?
Often, yes. Melasma is chronic, and even a good result can fade when the sun returns. About a quarter of those who improved in the Singapore series relapsed, and the international consensus stresses maintenance treatment to prevent relapse. Lasers and some other procedures carry a high risk of relapse in melasma and need expert use, which is the subject of can laser make melasma worse. The wider pattern of pigment returning is in why pigmentation comes back.
Daily sun protection is the mainstay of every plan, whatever else is added. Guidance asks for a broad-spectrum sunscreen with a high protection factor, ideally tinted with iron oxide because visible light can darken melasma, reapplied through the day, with a hat, shade and protection indoors near windows. Tinted sunscreens come in a limited range of shades, so where none suits, the consensus offers a non-tinted broad-spectrum sunscreen with iron oxide make-up in a matching tone. In Malaysian heat and UV that is a daily habit all year, and what the SPF number leaves out explains what ultraviolet A does that a single number misses. How the climate changes the disease is in melasma in Malaysia.
Everything above assumes the diagnosis is melasma. Sun spots and Hori's naevus can sit on the same cheek and are handled differently, and how to tell them apart sets out the difference.
