Lactic Acid

What it is

Lactic acid is derived from milk sugars (or produced synthetically for vegan formulations) and is part of the same AHA family as glycolic acid, but its larger molecule size means it typically penetrates more slowly and is generally considered milder. It's also a natural component of the skin's own moisturizing factor, which is part of why it's often described as more hydrating than other acids.

What it does

Lactic acid is an AHA with a larger molecule than glycolic acid, generally considered gentler and slightly more hydrating, making it a common entry point for people newer to chemical exfoliation.

Who it’s for

A common starting acid for people new to exfoliation, and often recommended for drier or more sensitive skin types compared with glycolic acid.

Possible benefits

• Associated with smoother texture with a comparatively gentler feel than glycolic acid
• Often described as more hydrating relative to other AHAs
• A reasonable starting point for people newer to chemical exfoliation

Irritation & compatibility considerations

Lactic acid is generally considered one of the better-tolerated acids, but it still increases sun sensitivity and can cause irritation, especially at higher percentages. The same general cautions apply as with any AHA: daily SPF, gradual introduction, and avoiding stacking with other strong actives in the same routine slot.

How it fits into a routine

Night use, a few times a week to start. Frequently found in gentler 'exfoliating toner' or lotion formats aimed at everyday use rather than intensive treatment use.