A retinoid is a class of compounds derived from vitamin A that are commonly used in skincare and dermatology. They help to promote cell turnover, reduce the appearance of fine lines and wrinkles, and improve skin texture. Retinoids can be found in both prescription and over-the-counter products, with varying strengths and formulations. These compounds work by binding to specific receptors in the skin, stimulating collagen production and encouraging the shedding of dead skin cells. Common types of retinoids include retinol, tretinoin, and adapalene. While effective, retinoids can cause skin irritation, so it's important to start with lower concentrations and gradually increase usage.