Muscle protein synthesis is a key process in muscle growth that aids in recovery and mass building.
Changes in muscle mass have an onset of 3-6 months and continue well into 1-2 years on therapy. As your testosterone levels decline, so does your metabolism for muscle protein synthesis. Due to this, there is less muscle growth in response to exercise and weight lifting. Not only will your muscles become less sensitive in terms of growth, but you will also lose muscle mass as well. This will affect your strength and you may find that you are not as strong as you were prior to starting therapy.
These changes can be reversed if androgen suppression therapy is stopped.
As you lose muscle mass, you will also lose some of your muscle definition. While on therapy, your body will begin to hold onto fat under the skin, which will also soften your definition. Studies have shown that those undergoing feminizing hormone therapy may not gain weight, but rather their weight will redistribute from muscle mass to fat content. Your shoulders and arms will become more feminine and slender, as well as the rest of your physique.
You should be aware that the skeletal anatomy you were born with will not change unless therapy was started before the completion of puberty.
Your height and shoulder width will remain the same.
Anatomy & Orientation
The illustration above depicts mature muscular anatomy of the biological male, post puberty. This image is representative of the starting point to your transitioning. The medical illustrator purposefully illustrated the figure with low body fat percentage and high muscle growth in order to depict muscle mass decline more effectively. This also emphasizes how muscle decline will result in a more feminine physique.
Muscular Changes Over a Timeline
Ghosted Muscle Anatomy
Increased Muscle Mass
No Breast Development
Muscle Mass Decline
Less Muscle Definition
Onset Breast Development
Leaner muscle mass
Increased Hip Diameter
Maximum Breast Development
Figures may appear idealized because they are based on an individual who already has a low body fat percentage and regularly exercises
This approach was taken to best depict the effects of therapy, so do not be discouraged if your muscle changes vary from the figures.
All changes from hormone therapy vary on an individual basis and rely upon genetics.
The illustrations above depict the muscular changes you could expect from therapy. You can follow the muscles that were defined in the first image decline in mass along the following two illustrations.
Although you may be holding on to less muscle mass, this should not discourage you from continuing a healthy exercise regimen. The CDC recommends 150-300 minutes of aerobic exercise a week with at least two days of strength training. The Physical Activity Guidelines for Americans (2nd Edition) from the CDC can be found here.