The injectable material that I see most frequently in patients presenting to my office is hydrogel. That is also probably the material that you may have heard of and seems to be the most popular for buttock augmentation. Hydrogel is a synthetic liquid polymer that is NOT approved for injection for ANY cosmetic indication in the United States. In other words, it cannot be obtained in this country except by illicit methods. We do not know the effectiveness or, more importantly, the safety of the material. So, fat taken from one part of your body and injected into the buttocks appears to be the safest material available at this point in time. Good luck!