Circatrigintan cycle of salivary testosterone in human male

Background. Circadian and circannual cycles of testosterone (T) in men are known. The results of our previous study have shown indices for the existence of a male circalunar cycle of T similar to the female one. Objective. The purpose of this study was to investigate possible infradian rhythms of salivary T in young healthy men. Subjects & Methods. Saliva samples from 31 healthy men (18-25 years of age) were collected every second day (for 1 month) and every third day (during the following 1.5 months). T levels were determined by radioimmunoassay. Data were statistically analyzed for infradian rhythmic changes using two different methods: moving averages - zones of extremes, and analysis of rhythmic variance. Results. The data showed rhythmic variations with 2 different infradian periods. The differences between extreme values of the circatrigintan (period of 30 days) and circavigintan (period of 20 days) cycles were found to be highly significant (p < 1E-9; p < 1E-8). Conclusion. We believe that this is the first study demonstrating the existence of circatrigintan and circavigintan rhythms of testosterone in human males. Our findings might have implications in human physiology and pathophysiology.