Twenty-four-hour mean plasma testosterone concentration declines with age in normal premenopausal women

J Clin Endocrinol Metab. 1995 Apr;80(4):1429-30. doi: 10.1210/jcem.80.4.7714119.


The 24-h mean plasma concentration of total testosterone (T) was measured in 33 healthy, regularly cycling, nonobese women between 21 and 51 yr of age. Percent free T was measured in 17 of them. Plasma dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) were measured in 24 of them, and the DHEA-to-T and DHEAS-to-T ratios were calculated. It was found that the concentration of total T showed a steep decline with age; the regression equation was: T (nanomoles per L) = 37.8 x age-1.12 (r = -0.54; P < 0.003). According to this equation, the expected T concentration of a woman of 40 would be 0.61 nmol/L, about half that of a woman of 21 (1.3 nmol/L). The percent free T did not vary significantly with age, so free T concentration likewise showed a steep decline with age. The DHEA-to-T and DHEAS-to-T ratios were both age invariant, clearly because the levels of DHEA and DHEAS also decline steeply with age, as previously reported.

MeSH terms

  • Adult
  • Aging / blood*
  • Circadian Rhythm*
  • Dehydroepiandrosterone / analogs & derivatives
  • Dehydroepiandrosterone / blood
  • Dehydroepiandrosterone Sulfate
  • Female
  • Humans
  • Middle Aged
  • Osmolar Concentration
  • Premenopause / blood*
  • Reference Values
  • Testosterone / blood*


  • Testosterone
  • Dehydroepiandrosterone
  • Dehydroepiandrosterone Sulfate