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Updated: Jan 15, 2026
Skeletal Muscle Gender Dimorphism from Proteomics
Published on: December 14, 2011
Muscle Strength and Power Changes With Gender-Affirming Hormone Therapy
Mathilde Kamp Nørlund1, Jakob Lindberg Nielsen2,3, Marianne Skovsager Andersen1
1Department of Endocrinology, Odense University Hospital, Odense, Denmark.
Background:
Androgen receptors are highly expressed in upper body muscles, but changes in maximal muscle strength and power in major upper body muscles have not been investigated during gender-affirming hormone therapy (GAHT).
Objective:
To assess prospective changes in maximal muscle strength and muscle power from before and after 1 year of GAHT.
Design And Methods:
Clinical prospective study in 92 transgender persons: 26 transmasculine treatment-naïve (TransM_naïve), 27 transmasculine treatment-ongoing (TransM_ongoing), 29 transfeminine treatment-naïve (TransF_naïve), and 10 transfeminine treatment-ongoing (TransF_ongoing) were examined at baseline and after 1 year of GAHT. Primary outcomes were unilateral upper body maximal muscle strength (kg) and mean and maximal power (watt) measured by low-row dynamic testing. Dual-energy X-ray absorptiometry was conducted in all participants.
Results:
In transmasculine persons, the median (quartiles) age was 22 (20; 30) years in TransM_naïve and 26 (22-29) years in TransM_ongoing (median GAHT duration 3 (2; 5) years) at study inclusion. Maximal muscle strength increased 6.3 kg (12%) in TransM_naïve (p ≤ 0.001) and 5.0 kg (7%) in TransM_ongoing (p ≤ 0.001), while maximal muscle power remained unchanged. ∆-muscle strength was positively associated with ∆-lean mass in arms and negatively associated with age at GAHT initiation. In transfeminine persons, the median age was 24 (22; 30) years in TransF_naïve and 40 (31-64) years in TransF_ongoing (median GAHT duration 4 (2; 6) years) at study inclusion. Maximal muscle strength decreased 17.5 kg (23%) in TransF_naïve and -5.0 kg (8%) in TransF_ongoing, which was accompanied by a decrease (23%) in maximal muscle power in TransF_naïve.
Conclusion:
Upper body muscle strength but not power increased during masculinizing GAHT, whereas muscle strength and power decreased within the first year of feminizing GAHT.
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