Does lunar cycle affect biological parameters in young healthy men?

This study aimed to assess the effects of the lunar cycle on diurnal variation of biological, , hormonal, biochemical, and hematological, profiles of diurnally active healthy men. Blood samples of 20 males were collected on four occasions [full moon (FM) and new moon (NM), in the morning (06:00-07:00 h) and evening (19:00-20:00 h)]. The results showed that melatonin and testosterone levels and neutrophils count were lower during the FM as compared to the NM in the morning ( < .001; = 4.13, < .001; = 3.84, < .01; = 0.77, respectively) and evening ( < .001; = 6.36, < .001; = 4.03, < .05; = 1.07, respectively) samples. However, cortisol level was higher during the FM compared to the NM, in the morning ( < .001; = 0.74) and evening ( < .001; = 3.54). Hemoglobinemia was higher only in the evening during the FM compared to the evening of the NM ( < .01; = 1.22). In summary, this study confirmed that lunar cycle can affect human biological parameters independently of time of day.