Is it dangerous to have hydrogel injected in the buttocks?

Hydrogel is not FDA approved for buttock augmentation. I do not recommend anything to be injected into the buttock for augmentation except your own fat.  Fat transfers to the buttock can give very natural, safe results. You can also use a gluteal implant for buttock augmentation however, they tend to have more complications than fat transfers.

Please consult with one or more board certified plastic surgeons prior to undergoing a buttock augmentation.

Best wishes,

Dr. Bruno

Allow me to answer your question another way.
The use of Hydrogel is Illegal in the USA. That means, that the FDA has not been convinced that its use is either safe and effective. ANY health care worker who administers Hydrogel risks losing his/her license and be the subject of Federal prosecution.
Also - of interests to the millions of lawyers out there, since the use of Hydrogel is NOT considered to be within the standard of care. Any complication regardless of severity, resulting from its use, automatically opens that health care worker to a lawsuit.
So - since most health care workers are FULLY aware of this, ask yourself, what kind of "doctor" would be willing to hurt me, risk loss of his/her license, risk Federal prosecution and expensive lawsuits?? - a really stupid callous one, in my opinion. Do you really want someone like this "treating" you?
Hope this answered your question.

Hydrogel is not approved by the FDA for injection in the U.S., therefore it should not be considered safe. There are proven techniques such as the Brazilian Buttock Augmentation which I routinely perform that are safe and very effective. This technique combines liposculpture to harvest (remove fat from unwanted areas) and re-injecting it into the buttocks to improve shape and firmness.
Dr. Sean Simon - check the Brazilian Buttock Lift section of before and afters for examples