PHA (Polyhydroxy Acid)
PHA (Polyhydroxy Acid) — a class of exfoliating acids often described as a gentler alternative to AHAs because of their larger molecular size. Examples such as gluconolactone and lactobionic acid exfoliate the skin's surface more slowly and also have humectant, water-attracting properties.
Key points
- PHAs have larger molecules than most AHAs, so they tend to penetrate more slowly and cause less irritation.
- Common PHAs include gluconolactone, lactobionic acid, and galactose.
- Many PHAs act as humectants, helping to draw and hold water in the skin.
- Their gentleness makes them a frequent choice for sensitive skin or those new to chemical exfoliation.
Frequently asked
How are PHAs different from AHAs?
PHAs have larger molecules that penetrate the skin more slowly, which generally makes them gentler than AHAs. Many PHAs also attract water, adding a hydrating benefit.
Are PHAs suitable for sensitive skin?
PHAs are often chosen for sensitive skin because their larger molecular size tends to cause less irritation than smaller acids. As with any active, patch testing is still a sensible precaution.
Related topics
This is a foundational entry in the SYNC Skin Encyclopedia and is expanded over time. Educational information only — not medical advice.
