The Ordinary's PHA 5% Exfoliating Lip Serum is a gentle chemical-based exfoliator for lips with 5% gluconolactone and 1.5% alpha hydroxy acids to smooth and hydrate lips. Gluconolactone is a polyhydroxy acid (PHA) that works to dissolve the structures that hold dead skin cells together. Due to their larger molecular weight, PHAs work on the surface of the skin to offer mild exfoliation, making them suitable for sensitive skin.. This formulation also includes a high concentration (>50%) of glycerin to improve hydration and retain moisture as well as ectoin to support the skin barrier and offer long-term hydration. PHA 5% Exfoliating Lip Serum helps to promote skin renewal on the lips to improve their overall appearance and texture over time.. PHA 5% Exfoliating Lip Serum can be layered under Squalane + Amino Acids Lip Balm to gently remove dry, dead skin and hydrate lips overnight.. Note: You may notice a slightly tangy taste when using this product. This comes from the exfoliating acids which help to gently renew and smooth lips.. Testing Shows. Gentle Exfoliation: Gently exfoliates and smooths lips while respecting the barrier. Smoothness: Promotes skin renewal for smoother-looking lips.. Shine: Gives lip a more radiant shine. Hydration: Increases moisture content by 30%* for plumper lips even when bare.. *Clinical testing on 22 subjects after using product 3x/week for 2 weeks.. How To Use. Apply a thin layer onto clean, dry lips on alternate evenings as needed. Allow the product to dry. Apply lip balm as needed throughout the day. If irritation occurs, rinse off, cease use, and consult a physician.. Use only as directed on unbroken skin.. Avoid contact with eyes.. Patch testing prior to use is advised. Refer to our website for a patch test guide, regimen guide, and product compatibility.. Keep out of reach of children.. It is recommended that prior to exposure to the sun, users apply sunscreen or an SPF lip balm.