Changes in muscle mass typically begin over the first 12 months and achieve maximum potential between 2-5 years. Testosterone therapy alone will increase muscle protein synthesis, making it easier to build muscle. With higher protein synthesis, your muscles will become more sensitive to bulking, and will hypertrophy faster and more noticeably if a proper weight lifting regimen is maintained. This concept goes hand in hand with increased strength, and you may be able to lift heavier than before. 

Muscle mass and strength changes may reverse if testosterone therapy is stopped.

The most noticeable area you will increase mass is in your upper body, giving it a more masculine silhouette. However, you should be aware that the skeletal anatomy you were born with will not change and you will continue to have the same height and width of your pelvic bones. This means that if you developed wide hip bones after puberty, you will still maintain the integrity of their shape.

The exception to this rule is with those who are undergoing therapy prior to the completion of puberty.

The illustration to the right depicts the muscular anatomy of an individual who has been undergoing testosterone therapy for 6-12 months. The illustration defines a few muscles of the upper body for you to follow in their growth presented in the illustrations below.


Muscle protein synthesis is a key process in muscle growth that aids in recovery and mass building.

Hypertrophy is the scientific word for muscle cell bulking. As your muscle cells enlarge, your muscle mass will as well. 

Anatomy & Orientation

Upper Body Muscle Anatomy

Rectus Abdominus
Pectoralis Major

Muscle Growth 

Ghosted Muscle Anatomy

Before Therapy

6-12 Months

2-5+ Years

  • Less Muscle Mass

  • Feminine Silhouette

  • Breast Fullness

  • No Facial or Body Hair

  • Muscle Mass Increased

  • Sharper Muscle Definition

  • Breast Fullness Decline

  • Increased Face & Body Hair

  • Maximum Muscle Mass

  • Increased Shoulder Width

  • Maximum Decrease Breast Tissue Decline

  • Maximum Face & Body Hair

Above you can visualize the potential of muscle mass development while undergoing therapy. These illustrations focus on the possible extension of muscle growth in contrast to the aspects about your physique that will not change. Things that will not change include: pelvic bone structure, height, and complete loss of breast tissue. These illustrations show a slight decrease in hip diameter, but that is only because testosterone therapy will cause your body to store less fat in your hips.  On the other hand, you can also observe other changes that will occur, such as body and facial hair growth.

The illustrations above depict the potential of increased muscle mass. The image furthest to the right illustrates the potential of muscle mass growth if you maintain a proper diet and exercise routine with strength training and a high protein intake. However, since these figures are based on an idealized physique, do not be discouraged if therapy alone does not give you the desired muscle growth you hope to achieve.


Unfortunately, pelvic bone structure will remain intact and you may not achieve the narrowed hips you desire. This is because biological men and women have a different pelvic bone structure. Pelvic bone structure may change, however, if therapy is started before puberty is completed.

These illustrations may appear idealized because they are based on an individual who already has a low body fat % and regularly exercises. 

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.

© 2019 Sam Nigro, Augusta University

Hormone therapy is not required for any transition or queer experience. Changes from hormone therapy that are outlined in this website are not guaranteed. All changes from hormone therapy are dependent on genetic makeup and can be different for everyone. 

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