For your skin
A fruit-derived AHA that exfoliates and antioxidizes. It shares the same basic mechanism as glycolic and lactic acid but is weaker gram-for-gram; in practice you'll see it doing dual duty (a little exfoliation plus pH stabilisation) in multi-acid toners and serums. When it appears low on an ingredient list, it's adjusting pH; higher up, it's contributing real exfoliation.
Want the science? Keep reading ↓Mechanism of action
Tricarboxylic AHA that weakens corneocyte cohesion in the same way as glycolic and lactic acids; included in Van Scott's landmark 25%-AHA study (glycolic, lactic, citric) that drove ~25% epidermal thickening over 6 months. Its antioxidant effect derives from chelating transition metal ions that catalyse free-radical reactions. In modern formulations it is more commonly used at low concentrations as a pH adjuster and preservative-system booster than as a primary exfoliant, where glycolic and lactic acids are more potent at equivalent pH.
Why we tier this anecdotal
2 cited papers across 2 countries. Most of what's cited here is mechanism-level or in-vitro work. We track this as Anecdotal until controlled clinical trials accumulate.
Cited research
Tang SC, Yang JH. Dual Effects of Alpha-Hydroxy Acids on the Skin. Molecules. 2018;23(4):863.
Ditre CM, Griffin TD, Murphy GF, Sueki H, Telegan B, Johnson WC, Yu RJ, Van Scott EJ. Effects of alpha-hydroxy acids on photoaged skin: a pilot clinical, histologic, and ultrastructural study. J Am Acad Dermatol. 1996;34(2 Pt 1):187-95.
Sources: PubMed · KCI · J-Stage · CNKI · Wanfang · SFD · MFDS · Cochrane · SCCS · CIR. Every entry points to a specific document. See methodology for what each outcome label means.