- A Swiss study found that young men who used cannabis had around 23% higher testosterone than non-users.
- The researchers also identified two possible hormone biomarkers that may help detect regular cannabis exposure.
- The findings do not prove cannabis improves fertility, and the clinical meaning of the hormone changes remains unclear.
Cannabis and male fertility have been debated for years.
Some studies have suggested cannabis may reduce sperm count, concentration or motility.
But evidence on testosterone has been inconsistent.
A new study from the University of Geneva looked at the question in more detail by measuring hundreds of steroid hormones in blood samples from young Swiss men.
The study included 47 confirmed cannabis users and 47 non-users aged 18 to 23.
The researchers found that cannabis users had about 23% higher testosterone.
By looking across a wider set of androgens, they traced the increase to the testes rather than the adrenal glands.
That suggests cannabis may be affecting Leydig cells, which produce testosterone.
The team also identified two progesterone-derived metabolites that were much higher in cannabis users.
These were hydroxyprogesterone and dihydroprogesterone.
The researchers suggest these may become useful biomarkers for tracking endocrine disruption linked to regular cannabis exposure.
But the fertility question is still unresolved.
Higher testosterone does not automatically mean better sperm quality or improved fertility.
The relationship between hormones and reproductive function is more complicated than that.
- Gut condition seen to be why cannabis users are ending up in A&E
- Lower back pain could be treated with cannabis extract
- Cannabis use may quadruple the risk of type 2 diabetes
It is also possible that the increase reflects a compensatory response, or that men with naturally higher testosterone are more likely to use cannabis because of risk-taking behaviour.
So this study challenges the simple claim that cannabis lowers testosterone.
But it does not show cannabis is harmless for male reproductive health.
The honest conclusion is that cannabis appears to alter steroid metabolism in young men, but what that means clinically still needs more work.
