Body fat redistribution typically begins within the first 6-12 months of therapy. While under the influence of estrogen, your body tends to store more fat than under the influence of testosterone. During hormone therapy, you will notice your subcutaneous fat becomes thinner over time. Studies have shown that transgender men will develop a lower body fat percentage over the course of therapy, however, this does not mean that you do not have the potential to gain fat. Rather, fat will redistribute and start to collect in different parts of your body.
These changes should finalize between 2-5 years of therapy. Changes in body fat distribution will reverse if testosterone therapy is stopped.
While under the influence of estrogen, your body will collect fat in the gynoid region; the region near your lower stomach and around the hips, thighs and buttocks. This area is presented in magenta on the figures to the right. Over time as your body readjusts to the testosterone, your body fat will migrate towards in your android region, or your “gut”. This area is illustrated in blue in the figures to the right. As your weight fluctuates naturally, you will find that your body stores less fat in the gynoid region and begins to store fat in your android region, giving you an “apple shape” body fat distribution as opposed to the “pear shape” that occurs under the influence of estrogen.
A poster illustrating this concept with data found from a study produced by the Endocrine Society can be found here.
Subcutaneous fat is the fat that exists directly under your skin. This is the same type of fat that will decline in your face, allowing you to have a more pronounced jaw bone.
Body Fat Regions
Body Fat Redistribution Along a Timeline
Gynoid Fat Collection
Less Muscle Mass
No Facial or Body Hair
Gynoid Fat Migration
Muscle Mass Increased
Breast Fullness Decline
Increased Face & Body Hair
Android Fat Collection
Maximum Muscle Mass
Increased Shoulder Width
Maximum Decrease Breast Tissue Decline
Maximum Face & Body Hair
Changes in breast definition also change due to fat redistribution. You may find that the fat in your breasts declines, and your breasts may lose some of their fullness. However, your breast tissue will not completely go away, and you may later consider breast reconstructive surgery.
Hormone therapy is not a prerequisite for breast reconstructive surgery, but many physicians recommend at least 6-12 months of hormone therapy before breast surgery. This is because the breast changes that occur with hormone therapy during that time may improve the final outcome of breast reconstructive surgery.
Significant weight gain in the android region is linked to metabolic syndrome. Metabolic syndrome is a collection of conditions such as high blood pressure, high cholesterol, and high blood glucose, rendering the individual prediabetic and at an increased risk for heart disease. Throughout your transitioning and beyond you should prioritize maintaining a healthy weight through regular diet and exercise.