Tranexamic acid started life as an oral antifibrinolytic used in medicine. Its skin-brightening effect was a side observation in melasma patients — and it turns out to be one of the better pigmentation-reducing actives available without prescription.
How it works on pigmentation
Tranexamic acid interrupts the signal between keratinocytes (skin cells) and melanocytes (pigment cells) that drives pigment production in response to UV and inflammation. This is different from hydroquinone (which kills melanocyte function) and vitamin C (which interrupts an enzymatic step) — the mechanisms stack.
For melasma specifically, randomised trials have shown topical 3-5% tranexamic acid comparable to 4% hydroquinone over 12 weeks, with much less irritation and no risk of ochronosis (the pigmentation rebound hydroquinone can cause).
Picking a product
The Inkey List Tranexamic Acid Overnight Treatment
2% tranexamic + 0.5% kojic acid. Affordable, well-tolerated, the UK starter.
Naturium Tranexamic Acid Topical Acid 5%
Higher concentration, US import but stocked at Cult Beauty UK.
Skinceuticals Discoloration Defense
4% tranexamic + 3% niacinamide + 1% kojic + 5% HEPES. Premium price, well-formulated, biggest evidence base.
How to use it
Apply twice daily after water-based serums, before moisturiser. Daily SPF is mandatory — pigmentation rebounds without UV protection regardless of treatment. Visible results in 8-12 weeks; full effect by 16-20 weeks.
Layers safely with niacinamide, vitamin C, and azelaic acid. Don't layer with hydroquinone (combine via your dermatologist if you're on the prescription) or with strong acids on the same routine step.
When to consider oral tranexamic instead
For stubborn melasma that fails topical treatment, oral tranexamic acid (250mg twice daily) has the strongest evidence of any oral pigmentation drug. It's prescription-only in the UK and requires screening for clotting risk — discuss with your GP or dermatologist. Not appropriate for everyone.
If you've tried vitamin C and azelaic acid without enough fade on pigmentation, tranexamic acid is the next logical step before moving to prescription options.