What does lactic acid do to your skin, is it harmful?
Arin Editorial · how this is made
You'll see 'Lactic Acid' on the labels of creams, serums, or peel products. Lactic acid is an alpha hydroxy acid (AHA) commonly used in skin-renewing products. Here's what it is and what to look out for when you see it on an ingredient list.
What is it and where is it found?
Lactic acid is a frequently used alpha hydroxy acid (AHA) in cosmetics. You'll see it on labels of skin-renewing products, creams, toners, and hair care products. It's used to dissolve dead skin cells on the skin's surface.
What does it do?
Exfoliating isn't its only job. It's a humectant: it draws water into the upper layers of the skin and helps keep it hydrated. It also lowers and balances the pH of a formula. In hair products, it softens strands and helps them look shinier.
Safety and limits
The independent CIR panel evaluated glycolic and lactic acid, their common salts and simple esters in 2013. Their conclusion: safe at concentrations of 5-10% when the final formulation pH is above 3.5. Additionally, one of two conditions is required: either the product is formulated to avoid increasing sun sensitivity, or the directions include daily sunscreen use.
EPA's laboratory screens found no effect on the estrogen receptor. This is from cell culture studies; it doesn't mean there's an effect in the human body.
However, toxicology database records show that pure, high-concentration lactic acid caused severe skin irritation, eye damage, and even corrosive effects in some animal tests. The same database also includes studies with no significant irritation. These records are hazard classifications; diluted, pH-adjusted cosmetic use doesn't carry the same risk.
The CIR panel found lactic acid safe for cosmetic use under specific concentration and pH conditions in 2013.
If you see lactic acid on a label and you're using the product for the first time, patch-test it on a small area. During daytime use, always apply sunscreen; that's part of CIR's safety condition. Stop use if you get burning, redness, or itching, and consult a doctor. Concentration and pH aren't listed on labels, so don't exceed the manufacturer's recommended frequency.
Sources
- CIR (Cosmetic Ingredient Review) 2013
- EPA ToxCast
- EPA ToxValDB
- SpecialChem
- Cosmacon