Testosterone Levels in Elderly Men

Testosterone levels gradually decline with age at an average rate of 1.6% per year, beginning in a man's mid-30s 1, 2
The incidence of low testosterone in the United States is approximately 50% in men older than 80 years, though the prevalence of syndromic low testosterone (defined as at least 3 sexual symptoms with a total testosterone level <320 ng/dL) is lower 2

Clinical Considerations for Elderly Men

The American Urological Association defines a testosterone level below 300 ng/dL as a reasonable cut-off to support the diagnosis of low testosterone across all adult age groups 3

The diagnosis of low testosterone should only be made after two total testosterone measurements are taken on separate occasions, both conducted in the early morning 3
Morning measurements are critical as testosterone levels naturally fluctuate throughout the day, with highest levels typically occurring in the morning 3, 4
When evaluating low total testosterone in elderly men with obesity, measurement of morning serum free testosterone is essential, as obesity affects sex hormone-binding globulin levels 5

Testosterone deficiency in elderly males is associated with energy imbalance, impaired glucose control, reduced insulin sensitivity, dyslipidemia, increased abdominal fat mass, and reduced lean body mass 5

Many men receive testosterone therapy without proper diagnosis - studies estimate that up to 25% of men who receive testosterone therapy do not meet the criteria to be diagnosed as testosterone deficient 3
Nearly half of men placed on testosterone therapy do not have their testosterone levels checked after therapy commences 3

The Endocrine Society recommends measuring bioavailable testosterone, which includes free testosterone and albumin-bound testosterone, to assess physiologically active androgen, particularly in men with obesity or conditions affecting SHBG levels 6

When evaluating low total testosterone in men with obesity, morning serum free testosterone measurement is essential, as obesity-related decreases in testosterone are frequently attributable to low SHBG concentrations, and these men may have normal free testosterone despite low total testosterone 6
Measuring bioavailable or calculated free testosterone is necessary when total testosterone is low-normal but clinical suspicion remains high, rather than assuming adequacy based on total testosterone alone 6