Validity of midday total testosterone levels in older men with erectile dysfunction

R. Charles Welliver*, Herbert J. Wiser, Robert E. Brannigan, Kendall Feia, Manoj Monga, Tobias S. Köhler

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Purpose Based on studies showing the circadian rhythmicity of testosterone the optimal time of day to draw total testosterone in men has classically been reported as between 8 and 11 a.m. However, further studies demonstrated that the testosterone circadian rhythmicity becomes blunted with age. Materials and Methods We retrospectively reviewed the charts of 2,569 men who presented with erectile dysfunction for total testosterone and draw times. We compared the men by age group, including less than 40 years and 5-year groupings after age 40 years. Total testosterone was analyzed for variability during the most common draw time hours (7 a.m. to 2 p.m.). Results Mean total testosterone at 7 to 9 a.m. and 9 a.m. to 2 p.m. clinically and statistically differed only in men younger than 40 vs 40 to 44 years old (mean difference 207 ng/dl, 95% CI 98-315, p = 0.0004 vs 149 ng/dl, 95% CI 36-262, p = 0.01). No other group showed a clinically and statistically significant difference between those periods. Conclusions Total testosterone in men with erectile dysfunction who are younger than 45 years should be drawn as close to 7 a.m. as possible because a statistically and clinically relevant decrease in testosterone will occur during the course of the day. Men older than 45 years with erectile dysfunction can have total testosterone drawn at any time before 2 p.m. without misleading results.

Original languageEnglish (US)
Pages (from-to)165-169
Number of pages5
JournalJournal of Urology
Issue number1
StatePublished - Jul 2014


  • age groups
  • circadian rhythm
  • erectile dysfunction
  • testis
  • testosterone

ASJC Scopus subject areas

  • Urology


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