Nelson Vergel
Founder, ExcelMale.com
"We demonstrate a clear seasonal fluctuation of both LH and testosterone in a large sample of adult human males. As expected, testosterone appears directly related to LH, but the annual fluctuation of these two hormones is not synchronous. LH shows a bi-annual fluctuation, with two peaks reached in spring and autumn, while testosterone shows only one summer peak. Moreover, the testosterone annual change shows a wider variability in annual values compared to LH, evident including levels below and above the laboratory reference ranges, while LH fluctuations remain irrespective of the reference range. Interestingly, the testosterone zenith is reached at least 3 months after the LH peak, a possible late consequence of the vernal LH peak. However, should this rhythmicity reflect a connection between the pituitary gland and the testicle, we should find two testosterone peaks every year. Rather, testosterone seasonal fluctuation could be mainly influenced by the environment. In particular, we show here an increasing trend of environmental temperatures across the years of observation, related to increasing testosterone serum levels. Moreover, when temperatures are higher during the year and the daylight duration is the longest (i.e., summer), testosterone serum levels reach their annual zenith. On the contrary, LH seasonality seems to be independent from environment, and a central mechanism, possibly regulating seasonal fluctuations of the hypothalamic gonadotropin-releasing hormone (GnRH), might be involved." Seasonal Changes of Serum Gonadotropins and Testosterone in Men Revealed by a Large Data Set of Real-World Observations Over Nine Years
