Hi there- Unfortunately, "reputable doctors... who offer Hydrogel injections for the buttocks" is an oxymoron... There are no reputable doctors doing this, as hydrogel injections are not safe, and have been associated with serious problems, including infection, necrosis of tissue, and even kidney failure and death. It is unfortunate that many nice people like yourself may not realize that things that sound too good to be true still are, even in today's world. The only safe way to increase the size and change the shape of your buttocks is through a safe surgical procedure provided by a surgeon certified by The American Board of Plastic Surgeons. Please follow the link posted to read more about this problem- and be careful! I have seen many women who would gladly pay whatever necessary to just be rid of the "hydrogel" and feel healthy again- but once placed it is very difficult to remove. Scary.