Thin lips can be caused by a variety of factors including genetics, aging, and environmental factors. There are several modern treatment options for thin lips, including:

Lip fillers: Lip fillers, such as hyaluronic acid fillers, can add volume and shape to the lips. These are injected into the lips using a fine needle, and the procedure is usually done in the doctor's office.

Lip augmentation: Lip augmentation is a surgical procedure that uses a synthetic or natural implant to add volume to the lips.

Lip lift: Lip lift is a surgical procedure that removes a small strip of skin from the upper lip, resulting in a more defined lip line.

Lip plumping products: Lip plumping products contain ingredients that can help to temporarily plump and volumize the lips.

Makeup: Makeup can be used to enhance the appearance of the lips. Lip liner, lipstick, and lip gloss can be used to create the illusion of fuller lips.