Diurnal Variation of Serum Total Testosterone in Women: A Single-Center Study From Basrah

Background The diurnal variation of testosterone in women has received limited attention, despite its growing recognition as a crucial factor in female health and well-being. This study aims to investigate the diurnal fluctuations of total testosterone levels in apparently healthy women with regular menstrual cycles. Methodology A cross-sectional study was conducted at Faiha Specialized Diabetes Endocrine and Metabolism Center in July 2023. This study involved 46 apparently healthy women volunteers aged between 21 and 40 years. To explore diurnal variations in total testosterone, blood samples were collected from each participant at two distinct time points, i.e., 8:30 AM and 1:30 PM. These samples were collected regardless of fasting status with the exclusion of the menstruating phase. Results The mean total testosterone level at 8:30 AM was 23.4 ± 12.4 ng/dL and at 1:30 PM was 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. Conclusions This study showed a significant diurnal variation in serum total testosterone levels among apparently healthy women, with higher levels observed in the morning.