Kojic Acid Just Hit a Ceiling in Europe. The Others Haven't.

The EU capped kojic acid and alpha arbutin in 2024 over safety concerns, azelaic acid is unrestricted in Europe but split between prescription and cosmetic strength in the US, and tranexamic acid has no concentration limit anywhere because no regulator has formally reviewed its topical use. The four ingredients most often marketed together for pigmentation carry four unequal levels of regulatory scrutiny.