INGREDIENT · PHA
Gluconolactone in skincare: the PHA, explained
Gluconolactone is the best-known PHA, a newer family of exfoliating acids sold as the gentle cousins of glycolic acid. The claim is plausible and mostly rests on a small body of older work.
You may see it written as
- Gluconolactone
What gluconolactone and PHAs are
PHAs, or polyhydroxy acids, are carboxylic acids with two or more hydroxyl groups attached to carbon atoms or an alicyclic chain. A 2010 review calls gluconolactone the most popular PHA marketed today. Lactobionic acid is another.1
The review lists PHAs as one of the classes of hydroxy acids, next to alpha hydroxy acids (AHAs), beta hydroxy acids and bionic acids.1 Whether PHAs behave like AHAs on skin is the question the rest of the page is about.
Are PHAs gentler than AHAs?
A 2004 review says PHAs provide effects similar to AHAs without the sensory irritation that can limit classical AHAs. It reports that they were compatible with clinically sensitive skin, including rosacea and atopic dermatitis, and that they add humectant and barrier benefits.2
That review summarises studies of PHA-containing products, often combined with other ingredients such as retinoic acid, retinyl acetate or hydroquinone, so it does not isolate gluconolactone. We found no recent independent trial that compares a gluconolactone product with an AHA product for stinging. Treat 'gentler' as a plausible claim with modest evidence.
Gluconolactone and the sun
The same 2010 review notes that the Cosmetic Ingredient Review panel advised that AHA products be formulated to avoid enhancing sun sensitivity, and that people use daily sun protection.1
For gluconolactone, one 2004 study measured it directly. In a lab model of photoageing, gluconolactone gave up to 50% protection against UV-induced damage, and in human skin it did not significantly increase sunburn cells.3 The 2010 review describes the human part as 11 volunteers who used an 8% glycolic acid lotion, an 8% gluconolactone lotion or nothing for a month. The glycolic acid site showed more sunburn cells and the gluconolactone site did not.1
It is a tiny study. It does not say gluconolactone is a sunscreen, and it does not remove the need for one.
Using gluconolactone with other products
The 2004 review reports PHA products used alongside retinoic acid in adult facial acne and describes them as well tolerated.2 Those are summaries of small studies, so treat them as a hint and not as advice to layer your own products.
Gluconolactone in pregnancy and breastfeeding
We found no pregnancy- or lactation-specific evidence for this ingredient.
Evidence on cosmetic products in pregnancy is limited overall, so ask your doctor or midwife about the specific product you use.4
What you will see on the label
On a label, look for Gluconolactone. Snifff shows it as Low risk. For the rest of the formula, see what the score means and how to read the list.
As Snifff shows itGluconolactone
Pregnancy and nursing
We found no pregnancy- or lactation-specific evidence for this ingredient.
Wording as it appears in the extension, which can change between releases.
A FEW MORE ANSWERS
Common questions about gluconolactone
What is gluconolactone?
A polyhydroxy acid (PHA), described in a 2010 review as the most popular PHA on the market.1
Is gluconolactone better than glycolic acid for sensitive skin?
A 2004 review says PHAs give AHA-like effects without the sensory irritation that can limit AHAs.2 We found no recent independent head-to-head trial.
Does gluconolactone make skin sun sensitive?
In one small study an 8% gluconolactone lotion did not increase sunburn cells in human skin, while 8% glycolic acid did.1,3 Use sun protection anyway.
Is gluconolactone the same as gluconic acid?
No, they are different molecules, but a 1997 study found that gluconolactone dissolved in water at room temperature gradually turns into gluconic acid.5 Look for the name gluconolactone on the label.
Is gluconolactone safe in pregnancy?
Snifff found no pregnancy-specific evidence for Gluconolactone. Ask your doctor or midwife about the product you use.
WHERE THIS COMES FROM
Sources
- Applications of hydroxy acids: classification, mechanisms, and photoactivityKornhauser A, Coelho SG, Hearing VJ · Clinical, Cosmetic and Investigational Dermatology · 2010
- The use of polyhydroxy acids (PHAs) in photoaged skinGrimes PE, Green BA, Wildnauer RH, Edison BL · Cutis · 2004
- The polyhydroxy acid gluconolactone protects against ultraviolet radiation in an in vitro model of cutaneous photoagingBernstein EF, Brown DB, Schwartz MD, Kaidbey K, Ksenzenko SM · Dermatologic Surgery · 2004
- Cosmetic dermatology in pregnancy and lactation: a risk-benefit framework for clinical practiceKovacs T, et al. · International Journal of Dermatology · 2026
- Tastes, structure and solution properties of D-glucono-1,5-lactoneParke SA, Birch GG, MacDougall DB, Stevens DA · Chemical Senses · 1997
This page explains an ingredient. It is not medical advice, and it is not an assessment of any product. If you are pregnant, breastfeeding, or have a skin condition, ask your doctor or pharmacist.