Juvederm Ultra will add volume and shape to your lips for up to one year. At that point, the body will fully absorb the hyaluronic acid and your results will begin to flag. Restylane Silk lasts around six months. Collagen lasts from six weeks to six months, as different people absorb it at different rates. Injected fat can last longer in some patients, but in others its duration seems to be about equal to Juvederm.