I call it a waist of your money! I have unfortunately had many patients come to me after having their high hopes for buttock augmentation crushed by measly Sculptra results. Critical points of awareness are: 1) Sculptra is temporary, it will last 1.5 - 2 years at most, 2) if done correctly dermal fillers like Sculptra are cost prohibitive for 99% of potential buttock augmentation patients. In order to create a significant/noticeable result with a dermal filler, at least 200 mls of product must be injected into each buttock cheek for a total of 400 mls. At $1000 per ml, this equates to a minimum price of $400,000.00. Thus if your doctor is recommending to put in ONLY 20 or 40 mls of sculpture you will pay $20,000-$40,000 and get an insignificant miniscule result!, 3) Do not let anybody tell you that the product is so special that it's going to magically grow over the following months or years...this just doesnt happen to any noticeable degree!, 4) dermal fillers, when injected in large quantities, have a relatively high infection rate, guaranteed tendency to migrate away from the original area they were injected into, and almost always stimulate a lot of inflammation with a subsequent and disastrous amount of scar tissue/hardening, and 5) the one very serious complication that can rarely (< 1%) happen is "embolism" in which some of the filler gets into the blood stream and travels up into the lungs, heart, and/or brain causing serious problems, including death.
Hope I at least saved you some money and maybe even your life.
There are only two safe and predictable ways to reshape and augment the buttocks: gluteal implant and fat transfer, which is also referred to as Brazilian buttock lift.
In case that your main concern is the appearance of sagging buttocks (due to massive weight loss), only an excision-based surgery can provide you good results.