Gluconolactone

Gluconolactone is a polyhydroxy acid (PHA) chemical exfoliant typically used around 2–15% at acidic-to-near-neutral pH, and is generally less irritating than glycolic or lactic acid due to larger molecular size and slower penetration. However, as an active exfoliant it can still cause stinging, dryness, or eczema flare in reactive or barrier-impaired patients, especially when combined with other actives or frequent use. For patient safety in sensitive populations, it warrants a mild irritancy score rather than being categorized as inherently gentle or inert. Safety Notes: In commercial skincare, gluconolactone (a PHA) is used at very low levels (~0.1–1%) as a mild chelating/antioxidant-supporting humectant in sensitive-skin moisturizers, toners, and barrier serums, where it is not positioned as the primary exfoliant. Most leave-on PHA exfoliating toners/serums and combination AHA/BHA/PHA products sit around ~2–10% (often pH-buffered for tolerability), aligning with published PHA exfoliation/anti-aging studies and common industry practice. The highest consumer-available strengths observed are ~15–20% in at-home “peel”/resurfacing treatments (typically leave-on for short contact time or rinse-off masks), which represent the upper end of OTC market offerings while remaining below professional-only peel conventions.