Related Experiment Video
Updated: Jul 12, 2025
11:51
Combining Behavioral Endocrinology and Experimental Economics: Testosterone and Social Decision Making
Published on: March 2, 2011
15.2K
Seasonal Variation in Serum Testosterone Levels: Evidence from 2 Large Institutional Databases
David Miller1, Aaron Gurayah2, Alexander Weber2
1Department of Urology, UPMC, Pennsylvania, USA.
Urology Research & Practice
|October 25, 2023
Summary
This study found no significant seasonal variations in testosterone levels in men across different climates. Testosterone testing can be done any time of year without seasonal adjustment.
Area of Science:
- Endocrinology
- Men's Health
- Clinical Chemistry
Background:
- Previous studies on seasonal variations in testosterone levels have yielded inconsistent results.
- Understanding potential seasonal influences on testosterone is crucial for accurate clinical interpretation.
Purpose of the Study:
- To investigate the existence of clinically relevant seasonal variability in testosterone levels.
- To compare testosterone levels in men from distinct climatic regions (seasonal vs. non-seasonal).
Main Methods:
- Analysis of a large cohort of men (ages 18-99) from Pittsburgh (seasonal) and Miami (non-seasonal) between 2010-2021.
- Utilized liquid chromatography with tandem mass spectrometry for testosterone level measurements.
- Excluded patients on testosterone-altering medications to prevent confounding.
Main Results:
- No statistically significant seasonal variation in total testosterone levels was observed in either Pittsburgh or Miami cohorts.
- Stratification by age group also revealed no significant seasonal variability in testosterone levels.
- A difference in overall testosterone levels was noted between the two climates, but not seasonally.
Conclusions:
- Findings suggest that seasonal changes do not significantly impact testosterone levels in men.
- Testosterone levels can be reliably checked and interpreted regardless of the season.
- This eliminates the need to consider the time of year when scheduling or interpreting testosterone tests.
Related Concept Videos
01:26Testosterone: Functions and Regulation
696
The intricate hormonal interplay essential for male reproductive health begins with the release of gonadotropin-releasing hormone (GnRH) by the hypothalamus. This hormone prompts the pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). LH targets the Leydig cells in the testes, stimulating them to produce and release testosterone. In concert with testosterone, FSH acts on the Sertoli cells within the seminiferous tubules to facilitate the release of...
696
01:20Disorders of the Male Reproductive System
431
Men's health issues are increasingly recognized as significant, with several conditions posing common threats. Among these, testicular cancer is especially prevalent in younger men, particularly those aged 20 to 35 years. The disease often manifests as a painless mass in the testicles, sometimes accompanied by a sensation of heaviness or a dull ache.
Prostate disorders are another major concern. These conditions can impair urinary flow due to the prostate's location around the urethra....
Prostate disorders are another major concern. These conditions can impair urinary flow due to the prostate's location around the urethra....
431
01:27Signs of Puberty
375
Puberty is a critical phase, typically beginning between the ages of 8 and 13 in girls and 9 and 14 in boys, though timing can vary based on genetics, environmental factors, and overall health. This period is characterized by the development of secondary sexual characteristics and the attainment of reproductive potential. Endocrine changes underpin puberty, with hormonal surges of Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) instigated by Gonadotropin-Releasing Hormone (GnRH)...
375
01:23Infertility in Males
276
Male infertility affects millions of couples worldwide, arising from various factors that impact different stages of the reproductive process. An endocrine imbalance resulting from conditions like hypogonadism, Klinefelter syndrome, or pituitary disorders can disrupt hormone levels and reduce sperm production. Testicular defects, such as tumors, cryptorchidism, atrophic testes, abnormal sperm morphology, and low sperm count or motility, may arise due to genetic factors, structural...
276
02:45Biological Clocks and Seasonal Responses
34.7K
The circadian—or biological—clock is an intrinsic, timekeeping, molecular mechanism that allows plants to coordinate physiological activities over 24-hour cycles called circadian rhythms. Photoperiodism is a collective term for the biological responses of plants to variations in the relative lengths of dark and light periods. The period of light-exposure is called the photoperiod.
34.7K
01:09Wilcoxon Signed-Ranks Test for Matched Pairs
140
The Wilcoxon signed-rank test for matched pairs evaluates the null hypothesis by combining the ranks of differences with their signs. It essentially tests whether the median of the differences in a population of matched pairs is zero. Since the test incorporates more information than the sign test, it generally yields more trustable conclusions. This test also does not require the data to follow a normal distribution, but two conditions must be met for it to be applicable: (1) the data must...
140