Several substances are used for buttock injections, ranging from your own body fat to synthetic fillers, but no injectable filler is currently FDA-approved for buttock augmentation. That distinction matters because it shapes the safety profile, legality, and longevity of every option available. Here’s what’s actually being used, how each one works, and what the risks look like.
Fat Transfer (Brazilian Butt Lift)
The most common method for buttock augmentation is autologous fat transfer, widely known as the Brazilian Butt Lift or BBL. A surgeon harvests fat from another part of your body through liposuction, processes it, and reinjects it into the buttocks. Most patients receive around 1,000cc of fat total, split between both sides. Thinner patients may get closer to 220cc per side, while plus-size patients can receive upward of 1,160cc depending on how much donor fat is available.
The catch with fat transfer is unpredictable survival rates. Your body reabsorbs 30 to 50 percent of the injected fat cells, meaning only about half of the initial volume typically remains long-term. In the best cases, around 70 percent survives. How much fat lasts depends on your genetics, the surgical technique, and how well you follow aftercare instructions.
Fat transfer also carries serious risks. By 2017, the BBL had earned the highest mortality rate of any cosmetic surgery, primarily from fat entering the bloodstream and traveling to the lungs. When large fat particles reach the pulmonary arteries, the event is almost always fatal. A review of 16 BBL deaths found that half of patients died on the operating table and the other half within three hours. Safety campaigns encouraging surgeons to inject fat only into the superficial tissue layer (not into or beneath the muscle) brought the estimated mortality rate down to roughly 1 in 20,000 by 2020. Still, in South Florida alone, 25 deaths from fat embolism were recorded between 2010 and 2022, with 92 percent of those surgeries performed at high-volume, budget clinics.
Recovery After Fat Transfer
Most surgeons recommend avoiding sitting directly on your buttocks for at least three to four weeks. During that window, you sleep on your side or stomach and use a specially designed BBL cushion that shifts your weight onto your thighs when you do need to sit. After the initial recovery period, you can gradually increase sitting time to about 30 minutes at a stretch, still using a cushion. Getting up and moving every 30 to 60 minutes helps reduce blood clot risk and supports circulation to the area.
Poly-L-Lactic Acid (Biostimulatory Filler)
Poly-L-lactic acid, sold under brand names like Sculptra, works differently from traditional fillers. Rather than adding volume directly, the injected particles trigger a controlled immune response. Your body sends immune cells to surround the particles, and in the process, nearby cells ramp up production of collagen and even stimulate new fat cell development. The result is a gradual increase in volume and improved skin quality that builds over weeks to months.
Results from PLLA typically last two years or longer, depending on your metabolism and lifestyle. Because the effect is gradual, multiple treatment sessions are usually needed. PLLA is not FDA-approved for buttock use, but it is used off-label by some dermatologists and cosmetic practitioners.
Calcium Hydroxylapatite
Calcium hydroxylapatite, marketed as Radiesse, is another biostimulatory filler sometimes used in the buttocks. For body applications, the product is diluted well beyond its normal concentration, which reduces its immediate volumizing effect and enhances its ability to stimulate collagen. For buttock sagging, a 1:2 dilution ratio is commonly referenced in clinical protocols. The goal is typically skin tightening and texture improvement rather than dramatic size increase, with results lasting at least seven months.
Hyaluronic Acid Fillers
Hyaluronic acid is the same naturally occurring substance found in popular facial fillers. For buttock augmentation, high-viscosity formulations are needed to provide structural support in a much larger treatment area. In Europe, products like HYAcorp MLF2 are used for this purpose. An earlier product called Macrolane, made by the same company behind Restylane and Juvederm, was once widely available but has been largely replaced.
HA fillers in the buttocks typically last 14 to 20 months before the body gradually breaks down and absorbs the material. One advantage of hyaluronic acid is that it can be dissolved with an enzyme injection if complications arise. These products are not FDA-approved for buttock use in the United States.
PMMA (Permanent Filler)
Polymethylmethacrylate, or PMMA, is a permanent filler made of tiny plastic microspheres suspended in a collagen solution. The product is designed to provoke tissue fibrosis, essentially encouraging your body to build scar tissue around each microsphere to create lasting volume. The problem is that this reaction can become uncontrolled, leading to foreign body granulomas: hard, inflamed masses that form as the immune system tries and fails to break down the plastic particles.
Complications are demonstrably more common with permanent fillers than with temporary ones. PMMA-related granulomas are notoriously difficult to treat. Surgical removal is generally not recommended because it can cause scarring, deformity, and residual inflammation from particles left behind. Medical management with steroid injections and other medications can help reduce the immune reaction, but there is no clear consensus on the best approach.
Illegal and Unregulated Substances
Outside of clinical settings, a dangerous underground market exists for buttock injections using nonmedical-grade substances. Industrial-grade liquid silicone is one of the most common. Injectable silicone is not FDA-approved for any aesthetic procedure. Other substances that have been documented in emergency rooms include mineral oil, cement, commercial adhesives, and even tire sealant. In one widely reported case, a mixture of cement, glue, mineral oil, and Fix-a-Flat was injected into a patient’s buttocks by an unlicensed provider.
Large-volume injections of these substances can cause life-threatening complications including pulmonary emboli (material traveling to the lungs), tissue death, severe infections, chronic pain, permanent disfigurement, and inflammatory masses that can appear months or years later. Migration of the injected material to other parts of the body is another documented risk, as is chronic lymphedema, a painful and persistent swelling condition. These procedures are often performed in private homes, hotel rooms, or unlicensed facilities, sometimes referred to as “pumping parties,” and they account for a disproportionate share of injection-related hospitalizations and deaths.
Why No Filler Is FDA-Approved for Buttocks
The FDA explicitly recommends against using any injectable filler for buttock augmentation or body contouring. This applies to every filler category: hyaluronic acid, PLLA, calcium hydroxylapatite, PMMA, and silicone. The buttocks require far larger volumes than the face, which amplifies the risk of vascular complications, migration, and immune reactions. When practitioners use these products in the gluteal region, they are doing so off-label, meaning the safety and efficacy for that specific use have not been evaluated through the FDA’s approval process. Fat transfer, while also carrying significant risks, is classified as a surgical procedure rather than a filler injection and falls under different regulatory oversight.