A Flat Buttock?
Hybrid Buttock Augmentation When You Have Little Fat There

Why a flat buttock is a concern

A buttock does not look flat only because of a lack of fat. Its overall shape is determined by gluteal fat, muscle, the way the pelvis and thighs connect, and volume in the upper and outer buttock. Especially in slim people or those with almost no buttock fat, dieting can further reduce volume that is already lacking. In this case, rather than simply filling in a lot of fat, it is important to create volume where it is needed and refine the surrounding lines. Buttock surgery is not just about increasing size; it is closer to body contouring that creates projection and the waist–pelvis–thigh connection together.

Why fat grafting is difficult when the buttock has little fat

Fat grafting buttock augmentation harvests fat from the abdomen, flanks or thighs and grafts it into the buttock. Its advantage is that it uses your own fat to contour the harvest site and improve buttock volume at the same time. But when there are not enough harvest sites, or when you need a certain degree of projection, it can be hard to plan with fat alone. Part of the grafted fat may be absorbed, so the size right after surgery is not maintained as is. In such cases, a hybrid approach can be used: the implant secures the base volume, and the available fat is used to refine the outer line and curves.

What is hybrid buttock augmentation?

Hybrid buttock augmentation uses a buttock implant together with fat grafting. The two are not simply done at the same time; each takes on a different role. The implant creates the central volume and projection of the buttock, while fat is used to soften the outer contour and the boundaries with surrounding tissue that an implant alone cannot express. This combined method has been described as a way to design projection and a natural appearance at the same time. Put simply, it is surgery that "creates volume" with the implant and "refines the line" with fat.

In a study of 147 patients who had implants and fat together, an average of 300 cc implants and 380 cc of fat were used, with the implant placed intramuscularly to create the central volume.^[1]

Related readingA plan that changes a flat buttock and the pelvic line together is covered in "Hybrid buttock augmentation: can a flat buttock and pelvic line be changed together?" (Korean).

What role do the implant and fat play?

The implant creates base volume and projection

For people with little buttock fat, an implant can make up for missing volume. Especially when you want three-dimensional projection in the center of the buttock, an implant makes it easier to design a size and shape that are hard to achieve with fat alone. In other words, the implant's biggest advantage is securing a certain volume even when fat is lacking. Implant-based buttock augmentation has been studied as a representative method for people without enough fat.

Fat refines a natural contour

Fat can be used to smoothly connect the areas around the implant, where the buttock meets the thigh, and hollows on the sides. This helps create a curve in which the whole buttock flows naturally, rather than emphasizing only the central volume created by the implant. Harvesting fat from the abdomen or flanks also has the advantage of refining the lines of those areas.

Advantages of hybrid buttock augmentation

The biggest advantage of the hybrid approach is that it uses both the reliable volume of an implant and the natural contour of fat.

First, base volume can be created even without much buttock fat.

Second, the outline and boundary areas that may fall short with an implant alone can be refined with fat.

Third, beyond enlarging the buttock, the lines of the abdomen or flanks where fat is harvested can be refined too.

Fourth, rather than simply making the buttock bigger, it is well suited to designing the proportions from waist to pelvis and pelvis to thigh.

Why it is possible even with little buttock fat

Many people ask, "Can I have fat grafting if I have no fat on my buttocks?" Hybrid buttock augmentation does not use only buttock fat. The needed amount of fat can be harvested from other areas such as the abdomen, flanks and thighs. So if your buttock is flat but you have some fat on the abdomen or thighs, a plan combining an implant and fat can be made. Conversely, if body fat is very low and not enough fat can be harvested, fat grafting cannot take a large share. In that case, creating the missing volume mainly with an implant can be the more direct approach. In short, a lack of buttock fat does not mean hybrid buttock augmentation is impossible.

How hybrid buttock augmentation differs from fat grafting

Fat grafting buttock augmentation enlarges the buttock with your own fat, while hybrid buttock augmentation adds an implant to secure base volume. So if you have enough fat and want a natural increase in volume, fat grafting can be used; but if fat is lacking and you want clear projection, the advantages of the hybrid approach grow. In particular, creating central volume with the implant and connecting the surrounding hollows with fat allows the line to be built more finely than with one material. However, injecting fat into the buttock carries serious risks such as vascular injury and fat embolism, so safe surgical principles — staying in a safe injection plane and using real-time ultrasound — are important.

How does volume change after surgery?

After hybrid buttock augmentation, the implant and fat change in different ways. The implant's volume is maintained as its position stabilizes after surgery, while part of the fat may be absorbed during recovery. So the buttock size right after surgery is not the same as the final volume.

At first, swelling can make the buttock look larger; over time, as swelling subsides and the fat stabilizes, the final line settles.

That is why, with hybrid buttock augmentation, it is important to look not only at the size right after surgery but at the overall curve once the implant's central volume and the fat have settled.

In a study that followed 50 patients with fat grafted into the buttock subcutaneous layer using ultrasound, the fat-layer thickness that increased right after grafting had decreased by an average of 18.2% at 12 months.^[2]

Hybrid buttock augmentation: common myths and facts