Great question.... my patients ask me this all of the time- right now I am using mostly Juvederm Vobella for lip lines, but will sometimes also use Restylane Silk. I will also add some botox or dysport to lengthen the life of the filler. You can typically except the filler to last 6 months- 1 year (maybe longer if you keep up with the botox). It all depends on how quickly your body breaks down the material. Hope this helps.
Belotero can last 6-8 months. Lip lines can also be improved with Botox. See an expert. Best, Dr. Emer