Chronic CBD exposure reduced testosterone and sperm quality in young male mice

Male Swiss mice at 21 days of age received oral CBD at 15 or 30 mg/kg daily for 34 consecutive days, with a control group receiving sunflower oil. After a 35-day recovery period, reproductive organs were weighed, testosterone measured, and spermatogenesis, sperm production, and sperm morphology were assessed through histomorphometry.

CBD is increasingly used chronically, including by young people and children with epilepsy. The finding that chronic exposure reduces testosterone, impairs sperm production, and causes morphological abnormalities raises important safety questions that have not been adequately addressed in human studies. The persistence of effects after a recovery period is particularly concerning.

As CBD products become mainstream wellness products used daily by millions, reproductive safety data become critical. This animal study adds to limited evidence suggesting cannabinoids may affect male reproductive function. The growing use of CBD in pediatric epilepsy makes these findings particularly relevant, as long-term treatment during development could have reproductive consequences.

This is a mouse study, and doses relative to body weight are much higher than typical human CBD use. The reproductive physiology of mice differs from humans in important ways. Only two doses were tested, and lower doses closer to human clinical use were not examined. The study assessed a single time point after recovery and could not determine if longer recovery would reverse the effects.