Lactic acid is one of the most widely used alpha hydroxy acids (AHA) in cosmetics thanks to its exfoliating, moisturizing and pH-regulating properties. Naturally present in fruits and fermentation processes, it has become a key ingredient both in professional treatments and in daily skincare formulations.
What is lactic acid and why is it important in cosmetics?
Lactic acid belongs to the family of AHAs (alpha hydroxy acids), known for their ability to remove dead cells and improve skin texture. Unlike other AHAs, such as glycolic acid or mandelic acid, lactic acid combines gentle exfoliation with moisturizing properties, making it ideal for sensitive skin.Benefits of lactic acid in cosmetic formulations
Gentle chemical exfoliation
Supports cell renewal, adds radiance and helps improve skin uniformity.Moisturizing and barrier-strengthening
Lactic acid is a humectant, meaning it attracts water into the skin, keeping it supple and hydrated.pH regulation in cosmetics
Beyond being an active ingredient, lactic acid works as a pH adjuster, essential in formulas requiring stability and skin compatibility.Preservation booster
Thanks to its ability to modulate pH, lactic acid can enhance the efficacy of preservative systems, providing an extra layer of safety.Enhancer of other actives
Promotes the penetration of ingredients such as peptides, vitamins and antioxidants.Comparison with other AHAs
- Glycolic acid → more powerful, but less tolerated.
- Mandelic acid → gentle, recommended for very sensitive skin or depigmenting treatments.
- Lactic acid → perfect balance between efficacy and hydration.
Concentrations and EU regulation
- Common use in leave-on cosmetics (creams, serums): up to 10% under safe conditions.
- In rinse-off products (cleansers, gels, exfoliants): higher concentrations with lower irritation risk.
- European regulation (Regulation (EC) No. 1223/2009) → sets maximum concentrations and labeling requirements, especially for professional peeling products.
- On the market, lactic acid is available in different purity concentrations (50%, 80% or 90%), allowing formulators to adapt it depending on the cosmetic application.
Most common cosmetic applications
- Facial creams for dry or dull skin.
- Exfoliating serums to improve skin texture.
- Facial cleansers that combine cleansing with cell renewal.
- Hair care products to balance the scalp.
Lactic acid derivatives
Beyond pure lactic acid, there are derivatives that expand its cosmetic applications:- Sodium Lactate: effective humectant and pH regulator.
- Potassium Lactate: conditioning agent with moisturizing properties.
- Zinc Lactate: helps regulate sebum and provides purifying effects.
- Calcium Lactate: fortifying, useful in formulas aimed at reinforcing the skin barrier.
- Ethyl Lactate: biodegradable solvent with good cosmetic compatibility.
Safety and precautions
Like all AHAs, lactic acid can increase sun sensitivity. It is therefore recommended to:- Use concentrated products preferably at night.
- Always accompany with sun protection during the day.
- Avoid aggressive combinations with other acids or retinoids without professional supervision.
Current trends in the use of lactic acid
- Bio-fermented lactic acid → more sustainable and natural origin.
- Synergistic blends with hyaluronic acid or niacinamide.
- Growing demand in vegan and cruelty-free cosmetics based on plant fermentation.