Allergan's Juvederm line consists of at least 9 fillers, all made of hyaluronic acid. Not all of them are available in the US. These differ in their cross-linking or "thickness" , from the least viscous Juvederm Hydrate all the way to Juvederm Voluma. Which one is indicated for lips? It all depends on what is available. In the US the initial recommendation was Juvederm Ultra or Ultra Plus because no other Juvederms were available. More recently Juvederm Volbella was approved by the FDA and it became Allergan's filler of choice for lips. In other countries there is also Juvederm Smile, indicated for lips. So there are no absolutes here except for your injectors preference or your desire if you have previous experience. Juvederm Ultra 2, 3 and 4 are not available in the US, but they have their equivalents, e.g.. Ultra 4 is Juvederm Ultra Plus. From those available in the US the Juvederm Ultra may have the shortest longevity, so it would make sense to use at least Ultra Plus or any other available Juvederms, including Voluma. There are many other great fillers that can be used for lips e.g.. Restylane line or Allofill. If you live in other countries your choice extends beyond these. The issue of longevity of Juvederms, as well as other fillers, is more confusing. On one hand the manufacturers claim certain longevity for each filler but you will not find anyone who will absolutely guarantee you that the injected filler will last that long. Here is an example that is not related to lips. One of the filler available in the US is Radiesse. It is a wonderful filler and at the time of its approval it was said that, on average, it would last about 18 months. Later on, a study was done on its longevity which revealed that 36 months later there was still approximately 10% of Radiesse remaining in tissue. It depends now what you do with this information. Yes, you can claim that there is a confirmed evidence that Radiesse may last up to 3 years but, if you look at it from more practical point of view, having 10% of filler left makes nearly zero impact on what you see in the mirror, not enough to give you any enhancement. If this is the first time you will have filler injection my suggestion would be not to jump to the most expensive filler, no matter whether it is "indicated" for lips or not. This would give you some idea about the longevity and the next time you may make a different choice. Your last concern about not looking fake is filler-independent. It is 100% dependent on the injector. Any fake lips you may see around are caused not by the type of filler but how and where it was injected. Always remember about the proportion between the upper and lower lip, quite intricate curvatures of both lips, and your own lip volume. Then, you may consider looking at the "before and after" photos, the work of your injector. Use rather less than too much. Good luck!