Research

Hormonal

In elderly men, bioavailable testosterone (specifically non-SHBG-bound T) is positively associated with muscle strength and bone mineral density, while being inversely associated with fat mass.

For elderly men experiencing muscle loss or bone density decline, standard total testosterone tests may be misleading due to age-related increases in SHBG. Bioavailable or free testosterone levels are better indicators of muscle and bone health. While this study is observational, it suggests that maintaining higher bioavailable testosterone is associated with better physical function.

ModerateSupportsMEDIUM confidence
T (total and non-SHBG-T) was positively related with muscle strength and total body BMD... An inverse association existed between T and fat mass... non-SHBG-T and calc-FT were more strongly related to muscle strength, BMD, and fat mass than TT
Annewieke W. van den Beld et al. · The Journal of Clinical Endocrinology & Metabolism · 2000

Why this rating

Cross-sectional observational study; strong statistical associations but explicitly states it cannot differentiate cause and effect.

Source

Measures of Bioavailable Serum Testosterone and Estradiol and Their Relationships with Muscle Strength, Bone Density, and Body Composition in Elderly Men*

Annewieke W. van den Beld et al. · The Journal of Clinical Endocrinology & Metabolism · 2000

DOI 10.1210/jcem.85.9.6825

cross_sectional · n=403Cited 607×
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DOI resolved against Crossref · corpus check 2026-06-10

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