Ruth, Sculptra is a unique filling product. It works more as a stimulator of your own collagen production rather than the material itself causing the volume increase. There is no permanence to Sculptra, so it will eventually all be dissolved and your collagen that was produced will also eventually thin again as you continue to age. The duration of Sculptra effect can last 2 years or so, depending on your body's response, once you have reached a full correction. You must commit to at least 2 or 3 treatment sessions on average to reach a full correction. Some patients require 4 or 5 sessions to reach full correction, depending on the extent of their aging and their skin's response to the material. A touch up at 18 to 20 months may prolong your effect. Good luck!