Normally, lip fillers last for between 12 and 18 months. However, if you have a higher metabolism rate, you may feel like your lip fillers are fading away sooner than usual.
As a rule of thumb, the younger you are the sooner you need to renew your lip fillers. In addition to metabolism, it’s also important what kind of product you are using.
For example, Juvederm Ultra Plus creates more dramatic results for those who like fuller lips, but it also fades away sooner than Restylane Kysse which creates more naturally-looking plump lips.