Full Breakdown
Cannabis Use Raises Testosterone in Young Swiss Men, Study Finds
5/28/2026, 8:05:08 PM
Study Overview
A joint study by the University of Geneva (UNIGE) and the Swiss Centre for Applied Human Toxicology (SCAHT) analysed plasma from 94 Swiss conscripts aged 18-23, equally divided between confirmed cannabis users and non-users. The research was led by Professor Serge Rudaz. Hormone profiling revealed a roughly 23 % higher testosterone level in users. Results appeared in *Communications Medicine* and identified two novel biomarkers of regular cannabis exposure.
Context and Prior Findings
Earlier work on cannabis and male reproductive hormones has been mixed: small studies linked use to reduced sperm count and lower testosterone, while recent large surveys in Denmark and the United States reported higher testosterone among users. The UNIGE analysis adds a mechanistic focus by pinpointing the rise to testicular Leydig cells, with unchanged adrenal androgen output.
Core Findings
- Sample: 94 conscripts (47 users, 47 non-users).
- Testosterone ~23 % higher in users; source is testicular Leydig cells; adrenal production unchanged.
- No direct link to improved sperm quality; increase may reflect compensatory response or behavioral correlation with higher baseline testosterone.
Interpretation and Criticism
UNIGE researchers stressed that the testosterone rise should not be taken as evidence of enhanced fertility, noting the hormone’s complex role and the possibility of a physiological compensation. The accompanying press release warned against extrapolating the finding to clinical outcomes and urged longitudinal research. Earlier studies have reported opposite effects, and some critics argue that short-term hormonal changes may not affect health and could be confounded by lifestyle factors. The present work does not determine whether the increase influences sperm quality, fertility rates, or overall reproductive health, and the mechanisms linking cannabis to Leydig-cell activity remain speculative.
Verbatim Quotes
- “Increase in Testosterone “Our results show that cannabis use would lead to an increase of about 23% in testosterone in young men,’’ explains Serge Rudaz.” — Serge Rudaz, Professor, UNIGE.
- “‘‘But by taking a closer look at all male sex hormones — the androgens — we were able to locate the source of this increase specifically in the testes.” — Serge Rudaz.
- “No direct link to fertility However, the researchers warned against interpreting the increase in hormone levels as an indicator of better sperm quality.” — SwissInfo press release.
- “The observed increase could be a compensatory reaction of the body to a reduced sensitivity of certain hormone receptors.” — SwissInfo press release.
Next Steps
The authors propose extended monitoring of cannabis-using cohorts to evaluate potential impacts on sperm quality and fertility over time. Validation of the newly identified biomarkers could improve epidemiological tracking of cannabis exposure in future research.
