INGREDIENT · ALPHA-HYDROXY ACID
Lactic acid in skincare: exfoliant, stinging and strength
Lactic acid is the gentler cousin of glycolic acid, but gentler does not mean it never stings. In fact, dermatologists use it as a deliberate stinging test.
You may see it written as
- Lactic Acid
What the trial found
A 22-week, double-blind trial gave 74 women aged 40 to 70 with moderately severe photodamage either 8% glycolic acid, 8% L-lactic acid or a vehicle cream, twice daily on the face and forearms. At least one grade of improvement was seen in 76% of the glycolic acid group, 71% of the lactic acid group and 40% of the vehicle group. The authors called both acids modestly useful, well tolerated and available without a prescription. One participant withdrew because of irritation.1
Note the vehicle number. Four in ten people improved on a plain cream, which is the reason the comparison matters. Lactic acid did better, but not by an amount you would call dramatic.
Why it stings
Lactic acid is used on purpose to find out who has sensitive skin. A lactic acid stinging test, in which a lactic acid solution is applied to the nasolabial fold, is a standard way to detect sensitive skin, and one study measured skin pH changes during it.2
How much it stings also depends on what it is mixed into. In a double-blind study, a water-in-oil emulsion caused less stinging than an ordinary oil-in-water one, and a formula at pH 3 without lactic acid stung significantly less than the lactic acid formula at the same pH.3 So the acid itself is part of the stinging, and the vehicle matters too.
Strength and pH: what EU guidance says
Neither region sets a binding cap. EU guidance recommends up to 2.5% lactic acid for home use at pH 5 or above; India has no equivalent guidance.
The figure in Snifff's summary comes from the EU's former cosmetics safety committee (SCCNFP). On the precautionary principle, it suggested lactic acid could be used safely up to 2.5% at pH 5.0 or higher.4
That is guidance, not a binding limit, which is why Snifff's summary says neither region sets a cap. The 2004 paper may have been replaced, and we have not checked.
Lactic 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 Lactic 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 itLactic Acid
Pregnancy and nursing
We found no pregnancy- or lactation-specific evidence for this ingredient.
Regulatory gap
Neither region sets a binding cap. EU guidance recommends up to 2.5% lactic acid for home use at pH 5 or above; India has no equivalent guidance.
Wording as it appears in the extension, which can change between releases.
A FEW MORE ANSWERS
Common questions about lactic acid
Does lactic acid work on photodamaged skin?
In a 22-week trial of 74 women, 71% of those using an 8% lactic acid cream improved by at least one grade, against 40% on vehicle. The authors called the effect modest.1
Why does lactic acid sting?
It is used as a deliberate stinging test for sensitive skin,2 and in a vehicle study the lactic acid formula stung significantly more than a lactic-acid-free formula at the same pH.3
What strength of lactic acid is considered safe?
The former EU cosmetics safety committee suggested up to 2.5% at pH 5.0 or higher, as precautionary guidance.4 Neither the EU nor India sets a binding cap, according to Snifff.
Is lactic acid safe in pregnancy?
Snifff found no pregnancy-specific evidence for Lactic acid. Ask your doctor or midwife about the product you use.
WHERE THIS COMES FROM
Sources
- Topical 8% glycolic acid and 8% L-lactic acid creams for the treatment of photodamaged skin: a double-blind vehicle-controlled clinical trialStiller MJ, et al. · Archives of Dermatology · 1996
- pH measurements during lactic acid stinging test in normal and sensitive skinIssachar N, et al. · Contact Dermatitis · 1997
- A double-blind and controlled study on the influence of the vehicle on the skin susceptibility to stinging from lactic acidSahlin A, et al. · International Journal of Cosmetic Science · 2007
- SCCNFP updated position paper concerning consumer safety of alpha-hydroxy acidsScientific Committee on Cosmetic Products and Non-Food Products, European Commission · 2004 · SCCNFP/0799/04, adopted 25 May 2004
- 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.