Delta-9 THC can be detected and quantified in the semen of men who are chronic users of inhaled cannabis.

Purpose: The purpose of this proof-of-concept study was to determine whether delta-9-tetrahydrocannabinol (THC) and THC metabolites (11-OH THC and THC-COOH) can be detected in semen.

Methods: Twelve healthy men aged 18-45 years who identified as chronic and heavy users of inhaled cannabis were recruited. THC and THC metabolite levels were measured in serum, urine, and semen of the participants. Semen analyses were performed. Serum reproductive hormones were measured.

Results: The median age and BMI of participants were 27.0 years and 24.7 kg/m, respectively. Over half the participants were daily users of cannabis for over 5 years. Serum reproductive hormones were generally within normal ranges, except prolactin, which was elevated in 6 of 12 participants (mean 13.9 ng/mL). The median sperm concentration, motility, and morphology were 75.5 million/mL, 69.5%, and 5.5%, respectively. Urinary THC-COOH was detected in all 12 participants, and at least one serum THC metabolite was present in 10 of 12 participants. Two semen samples had insufficient volume to be analyzed. THC was above the reporting level of 0.50 ng/mL in the semen of two of the remaining participants. Seminal THC was moderately correlated with serum levels of THC (r = 0.66), serum 11-OH THC (r = 0.57), and serum THC-COOH (r = 0.67). Seminal delta-9 THC was not correlated with urinary cannabinoid levels or semen analysis parameters.

Conclusion: This is the first study to identify and quantify THC in human semen, demonstrating that THC can cross the blood-testis barrier in certain individuals. Seminal THC was found to be moderately correlated with serum THC and THC metabolites.