Smooth Serum

Glycolic at 3%, lactic at 1% and gluconolactone at 1%. A low-strength night acid in a fluid base.

Three acids at low percentages. Glycolic is the smallest AHA molecule, so it moves fastest. Lactic is larger and holds water as well as exfoliating. Gluconolactone is a polyhydroxy acid and the slowest of the three. The total acid load is low, which is what makes this a nightly product rather than an occasional one.

Two things to know. Alcohol and witch hazel water sit high in the formula, and menthyl lactate gives a cooling hit on application — that sensation is the menthol derivative, not the acids working. It also declares linalool, citronellol, geraniol and citral.

At night, after cleansing, before your night cream.

Actives: Glycolic Acid (AHA) 3%, Lactic Acid (AHA) 1%, Gluconolactone (PHA, exfoliant) 1%, Hyaluronic Acid

Suits: Normal to oilier skin. Skin new to acids.

Not for: Skin that reacts to fragrance. Skin already on a nightly Vitamin A, without a plan.