A Brazilian Butt Lift (BBL) enhances the size and shape of the buttocks by transferring the patient’s own fat, a process known as autologous fat transfer. While initial results may appear dramatic, a reduction in volume is a common and expected part of the healing process. This reduction is caused by the resolution of temporary swelling and the natural biological process of fat cell survival. The final outcome depends on the body’s inherent healing response and the patient’s adherence to post-operative care instructions.
The Expected Process of Fat Resorption
The initial size reduction seen in the first few weeks is primarily the resolution of temporary volume. This immediate fullness is caused by the injected fat, residual fluid from liposuction, and surgical swelling (edema). As the body manages this trauma, inflammation and fluids dissipate, causing the initial size to decrease noticeably.
Permanent volume loss occurs because transferred fat cells (adipocytes) must establish a new blood supply to survive. This process of revascularization is biologically taxing, and not all cells integrate successfully. Only about 60% to 80% of the injected fat cells will survive and become a permanent part of the contour. The remaining cells are gradually resorbed and eliminated by the body.
This natural volume reduction, known as fat resorption, occurs predictably over the first three to six months post-surgery. The surviving fat cells stabilize and integrate during this period, which is when the final, stable result emerges. The fat that remains after six months is considered permanent and will behave like any other body fat. Surgeons often inject a higher initial volume to account for this expected loss.
Lifestyle Choices That Affect Graft Survival
The greatest influence a patient has on their final BBL volume is the meticulous avoidance of direct, sustained pressure on the grafted areas. Compressing the buttocks, such as by sitting or sleeping on the back, crushes the delicate new blood vessels forming around the transferred fat cells. This mechanical trauma starves the grafts of oxygen and nutrients, leading to cell death and greater volume loss. Patients must use specialized BBL pillows or lie on their stomach for several weeks to protect the grafts.
Nicotine use severely compromises the survival rate of the fat grafts. Nicotine is a potent vasoconstrictor, which narrows blood vessels. This constriction restricts blood flow and oxygen delivery to the grafted fat, suffocating the cells before they can establish circulation. This lack of nourishment increases the risk of fat necrosis, leading to greater volume loss and potentially uneven results.
Maintaining a stable nutritional intake is important during the healing phase. Fat grafts need energy to survive and integrate, so crash dieting or rapid weight loss negatively affects the outcome. Transferred fat cells shrink if the body is in a significant caloric deficit. Strenuous exercise that burns significant calories or places excessive pressure on the buttocks should be avoided during the initial recovery period.
Addressing Excessive or Uneven Volume Loss
When volume loss exceeds the expected 20% to 40% range, or if the resulting contour is asymmetrical, factors beyond natural resorption may be involved.
Surgical Technique and Injection Method
The technique used for harvesting and processing the fat is a contributing factor. Aggressive liposuction or improper handling can damage fat cells before transfer, reducing their viability. While purification steps like centrifugation isolate healthy cells, excessive force can damage the delicate adipocytes. The injection method also impacts survival; injecting too much fat into one area can overwhelm the local blood supply, causing cell death in the center of the graft.
Causes of Asymmetry
Uneven volume loss or asymmetry can result from differing graft survival rates between the two sides. This may be due to localized pressure applied during recovery or slight variations in the quality of the tissue at the recipient site. Scar tissue from prior procedures can also compromise the blood supply, making it difficult for new fat to survive in those areas.
Complications
In rare instances, excessive or rapid volume loss may be linked to complications. These include infection, seroma (fluid collection), or extensive fat necrosis. Fat necrosis occurs when a large cluster of transferred cells die and form a hard lump, which can distort the contour. Patients should consult their surgeon if they notice significant, rapid, or painful changes after the initial three-week period. A revision procedure may be considered after the six-month stabilization mark if the remaining volume is insufficient or the contour is significantly uneven.