PDO threads are a non-surgical cosmetic treatment that uses threads made of polydioxanone (PDO) to lift and tighten sagging skin. The threads are inserted under the skin and create a scaffolding effect, lifting the skin and stimulating collagen production. PDO threads can be used to lift and tighten the skin on the face, neck, and body, and can help to create a more youthful and rejuvenated appearance.