Free testosterone linked to muscle gene activity, not strength
In 81 healthy males aged 18–80, an observational study linked free testosterone to muscle gene activity, but not muscle mass or strength.
Limit: Age could confound the testosterone–gene activity link because both changed with age
Edited by Boris Djordjevic · AgingResearch.News
In an observational study, 81 healthy males aged 18–80 underwent body and muscle scans, leg-strength testing and thigh-muscle biopsies. Older age was associated with lower free testosterone, muscle mass and strength. Free testosterone—the portion not bound to proteins in blood—was strongly associated with patterns of muscle gene activity. Total testosterone was not. Neither measure was associated with muscle mass or strength.
The researchers also compared muscle cells grown in the lab from five young and seven older donors, with and without added testosterone. In these cells, testosterone increased the amount of its receptor, a protein that responds to the hormone. It also increased the receptor’s presence in cell nuclei, which house DNA.
Why it matters
Testosterone’s role in muscle aging remains unclear. The authors suggested it may mainly help establish male muscle characteristics during puberty, then take a supporting role in adulthood.
Caveats
The human findings were observational and cannot establish cause and effect; participants were healthy males aged 18–80. This bioRxiv preprint has not been peer-reviewed.
- Testosterone
- Free testosterone
- Total testosterone
- AR abundance and nuclear localization
- Leg press estimated one-repetition maximum
- Humans
The paper
Deakin University
bioRxiv, Oct 17, 2026, Open access, CC BY-NC-ND, Preprint, not peer-reviewed
