Lactic Acid

What is lactic acid?

Lactic acid is one of the alpha hydroxy acids, or AHA for short. It forms during fermentation, for example in yoghurt or sauerkraut, and for cosmetics it is usually produced by fermenting sugar. Your skin knows lactic acid well: its salt, sodium lactate, is part of the skin’s natural moisturising factor.

How does lactic acid work on the skin?

• Gentle exfoliation: lactic acid loosens the bonds between dead skin cells so they shed more easily.
• Smoother, brighter skin: rough patches, blackheads and a dull complexion visibly improve.
• Hydration: unlike many other acids, lactic acid also binds moisture.
• More even tone: used regularly, it helps fade dark spots and post-acne marks.

Lactic, glycolic or mandelic acid?

Glycolic acid is the smallest AHA; it penetrates fastest and works most strongly – but is also more likely to irritate. Lactic acid is slightly larger and therefore gentler. Mandelic acid is milder still. That’s why lactic acid is often the first choice for beginners, dry and sensitive skin.

Which skin types is lactic acid suitable for?

• dry, rough skin with flakiness
• dull skin and combination skin with blackheads
• AHA beginners and skin that doesn’t tolerate glycolic acid well
• for very sensitive skin or rosacea, only with caution and at a low concentration

How to use lactic acid

1. Start with 2 to 3 evenings a week – after cleansing and before serum and cream.
2. If your skin tolerates the acid well, you can increase slowly.
3. Follow with a soothing moisturiser.
4. Always wear sunscreen during the day – AHAs make the skin more sensitive to light.

What can you combine lactic acid with?

• Hyaluronic acid and ceramides counteract dryness
• Niacinamide supports an even skin tone
• Take care with retinol and BHA: use them on different evenings so as not to overload your skin.

Lactic acid in Korean skincare

Korean products often combine lactic acid with other acids. Examples from our range: the Chestnut AHA 8 Clear Essence by Isntree with 4% glycolic and 4% lactic acid, the AHA Aqua Peeling Boosting Ampoule by Centellian24, the Zero Pore One Day Peptide Serum by medicube, and the Glutathiosome Dark Spot Pad Vita Touch by Abib and 2% Salicylic Acid Clear Pad by Dr. Althea. You’ll find more products in our AHA skincare collection.

What does the research say?

In one study, a lotion with 12% lactic acid improved skin firmness and smoothness as well as the appearance of fine lines. It thickened both the epidermis and the dermis, while a 5% lotion acted mainly on the epidermis (Smith, Journal of the American Academy of Dermatology, 1996).