Adapalene is a medication used to treat acne. It belongs to a class of drugs called retinoids and is similar in function to vitamin A. Adapalene works by normalizing the growth and shedding of skin cells and decreasing inflammation. It is applied topically to the skin in the form of a gel, cream, or lotion. Adapalene is typically used once daily in the evening, and it may take several weeks to see results. Adapalene can cause some side effects, including skin dryness, itching, redness, and peeling. It may also increase the skin's sensitivity to sunlight, so it's important to use sunscreen and avoid excessive sun exposure while using this medication.