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PHA (polyhydroxy acids)

aka Polyhydroxy acids, PHA, Gluconolactone, Lactobionic Acid, Maltobionic Acid, Bionic acids

The short answer

PHAs such as gluconolactone and lactobionic acid exfoliate like AHAs but are bigger molecules that also attract water, so they tend to sting less. Most of the detailed research comes from NeoStrata, the company that developed them, so read 'gentle' as likely rather than guaranteed.

Known for
Gentle, larger-molecule acids that smooth skin and help it hold onto water.
Suits
Sensitive skin wanting gentle exfoliationDry or dehydrated skin
Helps with
Rough texture
Evidence
limited

Updated 5 Oct 2026 · Sources

Check first

Caution: Still an exfoliantCaution: Most data company-fundedCaution: SPF still needed
  • You're already using an AHA, BHA or retinol in the same routine; keep to one exfoliant at a time.
  • Your skin is broken, sunburnt or irritated.
  • You've reacted to an exfoliating product before; try it on your inner arm first.

What it goes with

Pairs well

  • CeramidesA barrier-supporting moisturiser after any exfoliant keeps skin comfortable.
  • Hyaluronic acidBoth attract water; a light hydrating layer suits PHA toners.
  • NiacinamideNo evidence of a clash; separate them if the combination stings.
  • PanthenolA soothing humectant that suits sensitive-skin routines.

Keep apart

  • Avoid: AHA (alpha hydroxy acids)One exfoliant per routine, even a gentle one, to avoid stacking irritation.
  • Avoid: RetinolThe AAD advises not exfoliating while using retinol. The developer reported PHA was compatible with prescription tretinoin, but that's company data on one formula, so alternate nights to be safe.
  • Avoid: Vitamin CTwo low-pH products together can sting; use them at different times of day.

How it works

PHAs are acids with several hydroxyl groups. The two you'll see most are gluconolactone and lactobionic acid; 'bionic acids' such as lactobionic and maltobionic acid are PHAs with a sugar molecule attached [1][2].

An independent review from the US National Institutes of Health describes PHAs as giving effects similar to AHAs but with less irritation, and as working as humectants and moisturisers with antioxidant activity [1]. The developers explain the gentleness by size: gluconolactone's molecular weight is 178, against 76 for glycolic acid, so it moves into skin more gradually [2].

The detailed numbers come from NeoStrata, which developed and sells PHAs. In its testing, a 12% PHA blend was non-irritating in a 14-day patch test of 26 people, scoring the same as saline [2]. In a NeoStrata-funded study of 31 women, an 8% lactobionic acid cream used twice daily for 12 weeks reduced measured fine lines by 37% and roughness by 70.8% compared with their starting point, but there was no plain-cream comparison on the face [3].

PHAs may also be easier in the sun. In company testing, gluconolactone didn't increase sunburn cells in the same model where AHAs did [2], and lab work suggests it mops up UV-generated free radicals rather than absorbing UV [1]. It isn't a sunscreen, so the usual SPF50+ rule still applies.

How to use it

  • Start two or three times a week, then build up; the developer's studies used twice-daily application for 12 weeks [3].
  • Keep to one exfoliant per routine and moisturise afterwards [4].
  • Strengths in studies: 8% lactobionic acid, 12% blends and 14% to 15% gluconolactone [2][3].
  • Wear SPF50+ every morning [6].
  • Try new products on your inner arm twice a day for 7 to 10 days first [7].

FAQ

PHAs give similar smoothing effects with less irritation and also attract water, according to an independent review [1].

Products with pha (polyhydroxy acids)

Each links to Australian stockists, with the price range across shops.

Sources

General information only, not medical advice.