Diurnal Variation of Serum Total Testosterone in Women: A Single-Center Study From Basrah.
Level 4 - case-series / case-control
Cross-sectional observational study evaluating paired time-point samples in a single cohort
PubMed 38021833 · doi:10.7759/cureus.47677
What was done
A cross-sectional study evaluated diurnal variations in serum total testosterone among 46 healthy female volunteers aged 21 to 40 years with regular menstrual cycles at a single center in Basrah in July 2023. Blood was collected from each participant at two distinct time points (8:30 AM and 1:30 PM) regardless of fasting status, with the exclusion of the menstruating phase.
What was found
Mean total testosterone was significantly higher at 8:30 AM (23.4 ± 12.4 ng/dL) than at 1:30 PM (21.7 ± 12.9 ng/dL), with a p-value of 0.03. Neither age nor body mass index demonstrated a significant impact on testosterone levels.
Why it matters
This study shows that circulating testosterone fluctuates during daytime hours in healthy women, emphasizing the need to standardize sampling time when measuring female androgen levels.
Limits
The study had a small sample size (n = 46) from a single center. Assessments were limited to two daytime points rather than a 24-hour circadian profile, fasting status was not controlled, and exact menstrual phases beyond excluding active menstruation were not tracked.
Cited by
- context Unlike men who experience a 24-hour diurnal testosterone rhythm, women experience a peak in testosterone in the week just prior to ovulation.