SOURCE-LINKED STUDY SUMMARY
Testosterone-induced increase in muscle size in healthy young men is associated with muscle fiber hypertrophy.
What was studied?
This dose-ranging study examined whether testosterone-related muscle enlargement reflects growth of individual muscle fibres.
What changed?
Thigh muscle volume rose with testosterone dose, from a 4 mL decline at 25 mg to a 48 mL gain at 600 mg weekly. Type I fibres enlarged significantly at 300 and 600 mg; type II fibres at 600 mg. Fibre-type proportions did not significantly change.
Who was studied?
61 healthy men aged 18–35 received treatment. Thigh imaging and paired muscle biopsies were studied in 39 men.
Studied exposure
Monthly injections of a hormone-suppressing GnRH agonist plus weekly testosterone enanthate injections of 25, 50, 125, 300 or 600 mg for 20 weeks. Comparisons were across dose groups and against baseline.
What remains uncertain?
Study limitations were not stated in the abstract. Methodological quality has not been appraised.
Review record & corrections
Summary prepared: . Source scope: abstract. This is an AI-assisted source summary, not an independent clinician sign-off.
No public field-by-field revision history is available for this card yet. The date above is the summary date, not proof that every field was updated then.
Inspect the source · Correction policyResearch findings apply to the population and conditions studied. This educational summary is not a treatment recommendation or a formal assessment of study quality.
Original publication ↗ · DOI: 10.1152/ajpendo.00502.2001