Researched by Helena DeMaria-Williams
Active IngredientAlpha Hydroxy AcidLactic Acid
INCI: Lactic Acid
Lactic acid is the second most well-researched alpha hydroxy acid (AHA), naturally found in milk and fermented foods. It has a larger molecular structure than glycolic acid, which means it penetrates the skin more slowly and gently while still effectively loosening the bonds between dead skin cells. Uniquely among AHAs, lactic acid also acts as a humectant, drawing moisture into the skin as it exfoliates.
Typical Concentration
Best For Skin Types
CAS Number
50-21-5
What are the benefits of Lactic Acid?
Is Lactic Acid safe? Key considerations
Can Lactic Acid cause irritation?
Low RiskLactic acid is one of the gentlest AHAs due to its larger molecule size, causing less stinging and burning than glycolic acid at equivalent concentrations. It is well-suited to sensitive skin types that struggle to tolerate stronger exfoliants. EU Annex III restricts AHAs in cosmetics: leave-on products must carry a sun sensitivity warning.
Does Lactic Acid increase sun sensitivity?
Yes RiskAs an AHA, lactic acid increases skin photosensitivity by removing the outermost layer of dead skin cells. Daily use of SPF 30+ is essential during and for at least one week after treatment to prevent UV-induced damage.
Is Lactic Acid safe during pregnancy?
CautionLow-concentration lactic acid (under 10%) in leave-on products is generally considered low risk during pregnancy. Professional-strength peels should be avoided. It is advisable to consult a healthcare provider, though topical AHAs at OTC concentrations are widely considered acceptable by dermatologists.
How does Lactic Acid work?
Lactic Acid is a alpha hydroxy acid active used across a range of concentrations depending on the application and product format.
Particularly beneficial for dry and sensitive and dull skin and hyperpigmentation and uneven texture and mature skin and anti-ageing concerns and most skin types skin.
Individuals with active skin wounds or irritation, very sensitive skin (patch test first), use alongside other AHAs or BHAs (avoid layering on same application) should review the considerations above before use.
How do you use Lactic Acid in your routine?
A step-by-step guide to introducing Lactic Acid into your skincare routine safely and effectively.
Choose the right concentration
Start with a product containing 5–10% for gentle daily exfoliation. Lower concentrations are better for beginners or sensitive skin.
Introduce gradually
Lactic Acid is generally well tolerated. Start by applying once daily and adjust based on how your skin responds.
Apply in the evening
Lactic Acid increases sun sensitivity, so use it in your evening routine. If you use it during the day, broad-spectrum SPF 30+ is essential.
Follow with moisturiser
After Lactic Acid has absorbed, apply a moisturiser to support your skin barrier. This is especially important when using active ingredients.
Wear SPF daily
While using Lactic Acid, apply broad-spectrum SPF 30+ every morning, even on cloudy days. Reapply every 2 hours if you're spending time outdoors.
Science & Research
Research references for this ingredient are coming soon.
Which products contain Lactic Acid?
Shop products that contain Lactic Acid
Advanced 0.2% Retinal Serum
360° Skin Clearing Serum
Hydrating Face Mist
Caffeine Solution 5% + EGCG Eye Serum
AHA 30% + BHA 2% Peeling Solution
Alpha Arbutin 2% + HA
Lactic Acid 5% + HA
Lactic Acid 10% + HA
