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Exfoliants & acne actives· in 1 product

PHAs

Also listed as Gluconolactone, Lactobionic acid, Galactose and Polyhydroxy acids

Emerging evidence 4–15% leave-on

Polyhydroxy acids (PHAs), mainly gluconolactone and lactobionic acid, are large-molecule exfoliants that work like AHAs but more gently. They also attract water, so they suit sensitive and dry skin.

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What it does

The short version.

PHAs loosen dead surface cells to smooth and brighten skin, but their large molecules penetrate slowly, which limits stinging. Their many hydroxyl groups bind water, giving a humectant, moisturizing effect, and they have antioxidant (chelating) properties. Brands position them for people who cannot tolerate glycolic acid, including some with rosacea- or eczema-prone skin.

Emerging evidence

Early clinical studies (several authored by researchers linked to the companies that developed PHAs) found antiaging effects comparable to an AHA regimen with less irritation; recent independent studies are small and focus on hydration measurements.

In our directory: It’s a key ingredient in 1 product we review, most often exfoliants & masks. Those products are mostly built for pore refining, clogged pores and smoothing. In formulas, it most often shares the label with salicylic acid, glycerin and hyaluronic acid.

Reach for it for

SmoothingResurfacingHydratingDullnessIrritation-free

Usually a good fit for

Sensitive skinDry skinNormal skinMature skin

How to use it

Getting it right.

Apply after cleansing, once daily or every other day, before moisturizer. Use sunscreen daily.

Layering

Friends & frenemies.

Pairs well with

Hyaluronic acidCeramidesNiacinamidePanthenolGlycerinRetinol

Go slow with

Glycolic acidSalicylic acid

Not forbidden — just easier to over-do. Alternate nights or separate morning and evening.

Before you start

Less irritating than AHAs but still exfoliants: stop if stinging or redness persists and avoid broken skin. Gluconolactone is related to AHAs, so sun protection is still sensible.

References

  1. 1The use of polyhydroxy acids (PHAs) in photoaged skin — Cutis (2004), via PubMed
  2. 2A polyhydroxy acid skin care regimen provides antiaging effects comparable to an alpha-hydroxyacid regimen — Cutis (2004), via PubMed
  3. 3Corneometric evaluation of skin moisture after application of 10% and 30% gluconolactone — Skin Research and Technology (2021), via PubMed

Educational, not medical advice. Ingredient guides summarise published research and expert guidance; formulas and concentrations differ between products.

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