Gluconolactone (PHA)
A polyhydroxy acid, the gentlest of the exfoliating acid families, studied for the appearance of a smoother surface with very little sting. Its molecule is larger still than mandelic acid, so it exfoliates mostly at the very surface and is generally considered suitable for skin that reacts poorly to AHAs and BHAs. It also functions as a humectant and mild antioxidant, part of why it shows up in sensitive-skin and rosacea-adjacent lines as an entry point into exfoliation.
Studied for
- ·The appearance of a smoother, more even surface
- ·The look of refined texture with minimal irritation
- ·The appearance of hydrated skin
- ·The look of a calmer surface for reactive or acid-sensitive skin
How it’s thought to work
A large multi-hydroxyl molecule that works mostly at the surface and is studied for gentle exfoliation plus humectant and antioxidant support; it is milder than AHAs and less likely to raise sun sensitivity. Its size limits how deeply it penetrates, the trade-off behind its gentler profile: less visible irritation, but a slower, subtler effect than a comparable percentage of glycolic or lactic acid.
A gluconolactone regimen was linked to smoother looking skin, similar to a glycolic acid regimen but with less visible irritation.
A polyhydroxy acid skin care regimen provides antiaging effects comparable to an alpha-hydroxyacid regimen. Cutis, 2004.
View on PubMed (PMID 15002657) ↗Questions
- Is a PHA strong enough to replace an AHA?
- Not really, and it is not meant to. Gluconolactone works at the very surface and is designed for gentleness, so it usually supports a routine or gives reactive skin an entry point into exfoliation rather than delivering the deeper resurfacing effects tied to AHAs like glycolic acid.
- Can I use a PHA every day?
- Many gluconolactone formulas are designed for daily use since irritation risk is low, but it is still worth introducing gradually and watching how skin responds, especially when pairing with other actives.
- Does gluconolactone raise sun sensitivity like AHAs do?
- Less so. Because it works mostly at the surface, it is generally considered less likely to raise sun sensitivity than glycolic or lactic acid, though daily sunscreen is still good practice with any exfoliating routine.