Can Juvederm Ultra 4 be used in the lips for volume? My filler is only lasting a few months 3 tops or is Volbella better?

We typically use the Restylane family- they have two relatively new products called Restylane Refyne and Restylane Defyne. These products have more cross linking of the HA molecules, so they are more flexible for natural filler results.  We are also seeing them last a bit longer if the lips. You would choose the Refyne if you want a more subtle, natural enhancement and Defyne if you want a more augmented lip.

Lip fillers, in my experience, usually last 6-9 months. I prefer the Restylane family of products in my clinic but I suspect you will see similar results with Juvederm. The problem with some of the thicker fillers like Juvederm UltraPlus is that it can result in a "stiff" lip which looks unnatural.