INGREDIENT · AHA
Mandelic acid for skin: peels, irritation and sun care
Mandelic acid is the AHA people reach for when glycolic acid stings. The evidence behind that reputation is thinner than the reputation, and one trial points the other way.
You may see it written as
- Mandelic Acid
What mandelic acid is
Mandelic acid is an alpha hydroxy acid (AHA). A 2019 trial describes it as one of the largest AHA peel molecules, which penetrates the skin slowly and uniformly, and calls it a good choice for sensitive skin.1
Read that as the authors' view, not a measured fact about your skin. It is also a description of peels given in a clinic. The leave-on creams and serums sold with mandelic acid on the label are a different product, and we found only a 2026 in-use study of a moisturiser that combined mandelic acid with Centella asiatica, in which skin crepiness, firmness and hydration improved over 12 weeks.2 It had two active ingredients and tested one company's cream, so it cannot isolate mandelic acid.
What the peel studies found
In the 2019 trial, 45 people with mild to moderate acne had peels every other week for six sessions. One group had 35% glycolic acid, one a combination of 20% salicylic and 10% mandelic acid, and one phytic acid. After 12 weeks acne scores had fallen by 70.55%, 74.14% and 69.7%, and no significant adverse effects were noted.1 The mandelic acid there was part of a combination, so the trial cannot say what mandelic acid did on its own.
A 2025 trial in India compared 30% mandelic acid with 30% lactic acid peels for dark circles around the eyes. Seventy people were randomised, with three peels at weeks 0, 2 and 4. Both groups improved, but the lactic acid group improved more: half of them had more than 30% improvement on a visual scale, and 100% were satisfied against 83.9% for mandelic acid.3
Both trials are small and short, and the authors of the 2025 one say so.3 They are a reason to take mandelic acid seriously, not a reason to buy any product.
Irritation and sun
The gentle reputation is not guaranteed. In the 2025 trial the side effects were mild redness and swelling, and irritation was more frequent with mandelic acid than with lactic acid. The authors suggest lactic acid may suit sensitive skin better.3
AHAs as a class also make skin more sensitive to the sun. A 2010 review reports that the Cosmetic Ingredient Review panel recommended that AHA products be formulated to avoid enhancing sun sensitivity, and that people be advised to use daily sun protection.4 We did not find a source specific to mandelic acid, so this is the guidance for AHAs as a group.
Using mandelic acid with other products
We did not find a source saying mandelic acid must be kept apart from another active, and the studies above tested peels in a clinic rather than layered products at home. If you are unsure, introduce one acid at a time, and stop if your skin stings or peels.
Mandelic acid 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.5
What you will see on the label
On a label, look for Mandelic Acid. 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 itMandelic Acid
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 mandelic acid
Is mandelic acid gentler than glycolic acid?
Researchers describe it as a large molecule that penetrates slowly, and recommend it for sensitive skin.1 We found no head-to-head trial against glycolic acid, and in one trial against lactic acid, mandelic acid caused more irritation.3
Does mandelic acid help acne?
A combination peel of 20% salicylic and 10% mandelic acid cut acne scores by about 74% over 12 weeks in 45 people, similar to glycolic and phytic acid peels.1 It is a small trial, and mandelic acid was not tested alone.
Does mandelic acid fade dark circles?
Both a 30% mandelic acid peel and a 30% lactic acid peel improved dark circles in a 70-person trial, and lactic acid did better.3
Do I need sunscreen with mandelic acid?
Yes, as with AHAs generally. The Cosmetic Ingredient Review panel advised daily sun protection with AHA products.4
Is mandelic acid safe in pregnancy?
Snifff found no pregnancy-specific evidence for Mandelic acid. Ask your doctor or midwife about the product you use.
WHERE THIS COMES FROM
Sources
- Comparative study of 35% glycolic acid, 20% salicylic-10% mandelic acid, and phytic acid combination peels in the treatment of active acne and postacne pigmentationSarkar R, Ghunawat S, Garg VK · Journal of Cutaneous and Aesthetic Surgery · 2019
- A novel moisturizer formulated with micronized Centella asiatica and mandelic acid improves mature, crepey skinAblon G, Emesiani C, Garimella S, et al. · Journal of Drugs in Dermatology · 2026
- A prospective study comparing clinical efficacy of 30% mandelic acid peel versus 30% lactic acid peel in periorbital melanosisMalviya A, et al. · Indian Dermatology Online Journal · 2025
- Applications of hydroxy acids: classification, mechanisms, and photoactivityKornhauser A, Coelho SG, Hearing VJ · Clinical, Cosmetic and Investigational Dermatology · 2010
- Cosmetic dermatology in pregnancy and lactation: a risk-benefit framework for clinical practiceKovacs T, et al. · International Journal of Dermatology · 2026
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.