Lips are the soft, fleshy structures that form the outer boundary of the mouth. They play a crucial role in various functions, including speaking, eating, and expressing emotions. The lips are made up of skin, muscle, and mucous membrane, which gives them their unique texture and color. They are highly sensitive and contain many nerve endings, making them important for the sense of touch. In humans, lips come in different shapes and sizes, influenced by genetics and ethnicity. The upper lip is typically thinner than the lower lip, and both can vary in fullness. Cosmetic procedures, such as lip fillers, are popular for enhancing lip appearance, while lip care products help maintain their health and softness.