Tranexamic Acid
Tranexamic Acid — evidence, uses & status

Class: small_molecule
Synonyms: TXA
trans-4-(aminomethyl)cyclohexanecarboxylic acid
INCI: Tranexamic Acid
tranexemic acid
tranaxemic acid
ranexamic acid
tranemic acid
Function tags: skin appearance (cosmetic)
hyperpigmentation appearance
even tone / brightening
melasma appearance
Overall evidence grade: B
WADA prohibited: no
Last updated: 2026-07-11

In brief: Tranexamic acid (TXA) is a synthetic lysine analogue, originally an antifibrinolytic medication, whose topical cosmetic form is a well-tolerated option for the appearance of hyperpigmentation — melasma above all. Rather than bleaching existing pigment, it calms the triggers of excess melanin by inhibiting plasmin. The evidence for the topical form is real and reaches meta-analysis level for melasma, but is graded B rather than A because the strongest review flags limited trial quality, much of the pooled data covers the oral/intradermal routes, and the benefit is narrow (pigmentation). The oral form has stronger data but is a prescription medicine and out of cosmetic scope.

## Identity

a synthetic **lysine (amino-acid) analogue** — trans-4-(aminomethyl)cyclohexanecarboxylic acid — originally developed as an antifibrinolytic medication to reduce bleeding. In skincare it is used as a small, stable, water-soluble **topical** active, typically at 2–5%, valued for its effect on the appearance of hyperpigmentation. For the full readable explanation of what it is and how it works, see the companion guide, [what is tranexamic acid?](/learn/what-is-tranexamic-acid)

## Development & history

- Developed in the mid-20th century as an antifibrinolytic **medication** (to reduce bleeding), still used medically in that role.
- Its effect on skin was discovered incidentally: melasma patients taking oral tranexamic acid noticed their pigmentation lightened.
- That observation drove interest in a **topical** cosmetic form, which grew into a mainstream brightening ingredient through the 2010s, often paired with niacinamide and vitamin C in tone-evening formulas.

## Mechanism (as proposed)

it works primarily by **inhibiting plasmin formation**, which interrupts the UV-driven cascade (UV → plasmin → arachidonic acid → prostaglandins → melanocyte activation) that stimulates excess melanin. It may also modestly reduce tyrosinase activity, and has an anti-angiogenic effect that addresses the vascular, redness component of melasma. The net cosmetic action is to **calm the triggers of pigment** rather than to bleach existing pigment — which is why results are gradual and depend heavily on daily sun protection.

## Related reading

- Where tranexamic acid ranks among the pigment actives, in [best ingredients for dark spots and hyperpigmentation](/learn/best-ingredients-for-hyperpigmentation).
- Post-inflammatory hyperpigmentation (a tranexamic use) versus the red marks it's often confused with, in [PIE vs PIH](/learn/pie-vs-pih).
- The other gentle tyrosinase-blocking brighteners, in [alpha arbutin](/learn/what-is-alpha-arbutin) and [kojic acid](/learn/what-is-kojic-acid).

Evidence grades by outcome:
outcome: Topical: melasma (products typically 2–5%)
grade: B
base: Systematic review and meta-analysis of 21 trials (Zhang 2018) reporting reduced Melasma Area and Severity Index (MASI) and Melanin Index with only minor side effects; topical split-face RCT and mechanistic work (Kim 2016) support both efficacy and the plasmin-inhibition mechanism; comparable to hydroquinone in head-to-head work with fewer irritant reactions
effect: Gradual, visible evening of melasma-related pigmentation over weeks to months, with a milder tolerability profile than hydroquinone
caveat: The meta-analysis itself cautions the underlying trials are of limited methodological quality; much of the pooled evidence covers oral and intradermal routes rather than the topical cosmetic form; topical is milder than oral; not FDA-approved for melasma
outcome: Topical: post-inflammatory hyperpigmentation & general uneven tone
grade: B
base: Mechanism (Maeda 2022) and dermatology reviews (Forbat 2019) support a pigment-calming action beyond melasma; direct trial evidence is strongest for melasma, with PIH and general tone benefit largely by extension
effect: Modest improvement in the appearance of dark spots and uneven tone
caveat: Less direct trial evidence than for melasma; effects are gradual and depend on rigorous daily sun protection
outcome: Safety (topical cosmetic form)
base: Widespread cosmetic use at 2–5%; controlled topical studies
effect: Generally well tolerated, with fewer irritant reactions than hydroquinone
caveat: Patch test and introduce gradually on sensitive skin. The ORAL form is a separate, prescription antifibrinolytic medication — out of scope for this cosmetic grade

Legal status:
region: INT
status: Lawful topical cosmetic ingredient
note: Topical tranexamic acid is a lawful cosmetic ingredient, CosIng-listed in the EU (Regulation (EC) 1223/2009) and used in cosmetic brightening formulas (typically 2–5%). Separately, ORAL tranexamic acid is a regulated prescription medicine (antifibrinolytic) in the EU, UK, and US — a medical product outside the scope of this cosmetic register entry.

Cosmetic claims:
allowed: for the appearance of a more even, brighter-looking complexion
helps reduce the look of dark spots and uneven tone
for the look of a clearer, more uniform complexion
supports a more radiant-looking complexion
forbidden: treats melasma
treats hyperpigmentation
cures dark spots
inhibits melanogenesis
inhibits plasmin
reduces inflammation
anti-inflammatory
bleaches or lightens the skin
an antifibrinolytic treatment

Honest note: This entry grades the TOPICAL cosmetic form only (products typically 2–5%), framed around the appearance of skin tone. Oral tranexamic acid is a prescription antifibrinolytic that affects blood clotting; it has stronger data for moderate-to-severe melasma but carries real contraindications (a history of clots, stroke, or certain cardiovascular conditions) and side effects, and is a decision for a dermatologist — not something to self-manage. Persistent or severe pigmentation such as melasma is best assessed by a dermatologist, and daily broad-spectrum sunscreen is essential with any pigment ingredient.

Sources:
Zhang L, Tan W-Q, Fang Q-Q, et al. Tranexamic Acid for Adults with Melasma: A Systematic Review and Meta-Analysis. BioMed Research International. 2018;2018:1683414.
Kim SJ, Park JY, Shibata T, Fujiwara R, Kang HY. Efficacy and possible mechanisms of topical tranexamic acid in melasma. Clin Exp Dermatol. 2016;41:480-485.
Maeda K. Mechanism of Action of Topical Tranexamic Acid in the Treatment of Melasma and Sun-Induced Skin Hyperpigmentation. Cosmetics. 2022;9:108.
Forbat E, Al-Niaimi F, Ali FR. The emerging importance of tranexamic acid in dermatology. Clin Exp Dermatol. 2019;45:445-449.