Erica, Thanks for the question. The most commonly used lip fillers in our practice are hyaluronic acids, including Juvederm Ultra and Restylane. Although the use of these products is off-label in the lips, their results are highly predictable, reproducible, and reversible with the use of hyaluronidase. The longevity of these products are typically in the 6 to 12 month range. Additionally, they have no intrinsic allergic components, as compared to their collagen counterparts. An alternative to hyaluronic acid as a lip filler is autogenous fat. Fat augmentation of the lips has a very predictable and natural appearing result. The advantage of this "filler" over hyaluronic acid is that it will theoretically last indefinitely, following the predictable amount of atrophy that occurs in the first several weeks following the procedure. The disadvantage, of course, is that fat augmentation is a surgical procedure with a greater amount of post-procedural swelling, bruising, and subsequent downtime than its hyaluronic acid filler counterpart. Regardless of what procedure you choose, review all your options with your plastic surgeon so that you may make an educated choice. Best of luck.