Lactic acid
Lactic acid is the mildest of the exfoliating acids. It's actually part of what your skin uses to hold onto water, so at low strengths it behaves more like a moisturizer than a peel, and it stings less than glycolic acid. If you get dry, rough patches it can feel nice. But it's still an acid: stronger versions make skin more sun-sensitive, and teen skin already renews itself just fine. A nice-to-have, never a need.
what the evidence says
Lactic acid is part of skin's natural moisturizing factor and is less irritating than glycolic acid; AHAs' UV effects are concentration-dependent, so exfoliating acids carry a sun caution.
can you use it with…
- Salicylic acidCareful
Mild plus mild is still a double exfoliant
- Strong acid peels (glycolic and friends)Not together
Two AHAs is just one big peel
sources
note:Skinformed is general education, not medical advice. It doesn't know your skin, can't diagnose anything, and is no substitute for a clinician. If something on your skin hurts, spreads, or worries you, that's a doctor visit, not a product search.