Explore testosterone research on muscle size, lean mass, strength and physical function. These outcomes and the populations studied are not interchangeable.
Browse the studiesDistinguish replacement in deficient patients from supraphysiologic experimental exposure.
Read resistance training, nutrition and hormone-suppression methods.
Keep measured lean mass separate from strength and long-term safety.
Selected from the completed-summary collection, not a systematic review or exhaustive literature search. Human reports appear first; reviews and preclinical work retain their labels.
A randomized dose-response experiment compared five testosterone-enanthate groups over 20 weeks after suppressing participants' natural testosterone production. Energy and protein intake were standardized.
No author-stated limitations were available in the abstract. This was a 20-week experiment with experimentally suppressed natural testosterone, rather than an untreated comparison.
Randomized trial comparing weekly testosterone enanthate or placebo, each with or without standardized resistance training.
This was a small, 10-week study in normal men using a supraphysiologic regimen. The abstract reports mood and behavior but no longer-term safety assessment or author-stated limitations.
A randomized trial tested testosterone added to nutrition and exercise for cirrhosis-associated muscle wasting.
Abstract-based assessment. No placebo comparator was described; attrition and incomplete safety detail matter. Disease-specific DEXA results cannot establish healthy-lifter hypertrophy or long-term safety.
This randomized study tested whether an eight-hour daily eating window changes body composition, strength, metabolism and biomarkers during resistance training.
The short study included only experienced, steroid-free men, so it does not establish longer-term effects or generalize to women, novices or enhanced athletes.
A randomized trial tested whether testosterone could improve strength, body composition, physical function, symptoms, and quality of life in frail older men with low or borderline-low testosterone.
This was a single-center, six-month study in older frail men. The abstract does not report adverse-event results, and DXA lean mass is not a direct measure of muscle hypertrophy.
A randomized, double-blind human trial tested testosterone dose responses, with comparison against previously studied younger men.
The age comparison used previous younger-men data rather than concurrent age groups. No author-stated limitation was available in this abstract.
A randomized placebo-controlled study tested androgen effects on muscle and bone in men requiring long-term systemic glucocorticoid treatment.
The study addressed a glucocorticoid-treated clinical population and cannot be used to infer the effects or safety of anabolic treatment in healthy athletes.
A 180-day active-comparator study evaluated transdermal testosterone gel effects on sexual function, mood, strength, DXA body composition, and safety in hypogonadal men.
This abstract assessment reports no placebo group. DXA lean mass is not direct muscle-size measurement, and the dose-adjustment design complicates fixed-dose comparisons.
A double-blind comparison examined how androgen doses affected body composition and muscle strength in healthy men.
The authors describe detectable changes beyond weight gain as highly variable and relatively small.
A muscle-biopsy analysis examined whether testosterone-associated fiber growth accompanies increases in satellite cells and muscle-fiber nuclei.
These are associated cellular changes; the analysis does not establish that satellite-cell increases caused hypertrophy or persisted after treatment.
This dose-ranging study examined whether testosterone-related muscle enlargement reflects growth of individual muscle fibres.
Study limitations were not stated in the abstract. Methodological quality has not been appraised.
A double-blind crossover experiment examined whether methandienone (Dianabol) changed body composition, strength, performance and endocrine function during weight training.
The authors could not establish whether the body-composition changes reflected an anabolic effect or increased intracellular fluid.
This Endocrine Society clinical-practice guideline addressed evaluation and treatment of androgen-deficiency syndromes in adult men.
The panel advised against starting therapy with breast or prostate cancer, high hematocrit, severe untreated sleep apnea, severe urinary symptoms, or poorly controlled heart failure.