Cannabis is one of the most widely used recreational drugs in the world, but scientists are still trying to understand exactly how it affects the human body. One area that has attracted significant attention is male reproductive health.
Many people have heard claims that cannabis lowers testosterone, reduces fertility, or harms sperm production. Yet scientific studies have often reached different conclusions.
A new study from the University of Geneva may help explain why the picture has remained unclear. Instead of finding lower testosterone levels in cannabis users, researchers found the opposite.
Young men who used cannabis actually showed higher testosterone levels than non-users. The research was published in Communications Medicine and provides new insight into the complex relationship between cannabis and the hormonal system.
The study was conducted by researchers from the University of Geneva and the Swiss Center for Applied Human Toxicology. The team wanted to look beyond testosterone and explore how cannabis might influence a wide range of hormones involved in male health.
The body’s hormonal system is incredibly complex. Hormones act as chemical messengers that help control growth, mood, metabolism, reproduction, and many other functions.
Testosterone is one of the best-known hormones because it is closely linked to male reproductive development and sexual health. However, testosterone works together with many other hormones, making it difficult to understand its role in isolation.
To investigate, researchers examined blood plasma samples from 94 young Swiss men between 18 and 23 years old. Half of the participants were confirmed cannabis users, while the other half did not use cannabis. Using advanced laboratory techniques, scientists measured hundreds of hormone-related substances in each blood sample.
This approach was different from most previous studies, which typically focused only on testosterone. By studying a much larger group of hormones, researchers hoped to gain a clearer understanding of what was happening inside the body.
Their analysis revealed that cannabis users had significantly higher testosterone levels. On average, testosterone concentrations were about 23 percent greater among users than among non-users.
The researchers then looked deeper to identify where this increase was coming from. They found evidence suggesting that the testes were responsible for the extra hormone production. Specifically, cannabis may influence Leydig cells, which are the cells responsible for producing testosterone.
At the same time, the researchers discovered two hormone-related compounds that were strongly associated with cannabis use. These substances, hydroxyprogesterone and dihydroprogesterone, come from progesterone metabolism.
Their levels increased so dramatically among cannabis users that researchers believe they could eventually be used as biomarkers to identify regular cannabis exposure.
This discovery is important because it expands scientific understanding beyond testosterone alone. It suggests that cannabis may affect a much wider range of hormones than previously recognized.
Despite these findings, the researchers caution against drawing simple conclusions. Higher testosterone does not necessarily mean better fertility. Fertility is influenced by many factors, including sperm count, sperm movement, sperm structure, hormone balance, and reproductive organ function.
In fact, some previous studies have suggested that cannabis may negatively affect sperm quality even when hormone levels remain normal. This means that testosterone is only one piece of a much larger puzzle.
The researchers propose several explanations for their results. One possibility is that cannabis affects hormone receptors, making them less responsive. In response, the body may produce more testosterone to compensate.
Another possibility is that individuals with naturally higher testosterone levels may be more likely to participate in behaviors such as cannabis use.
Because the study observed existing cannabis users rather than assigning people to use cannabis, it cannot determine which explanation is correct. More research will be needed to establish cause and effect.
One of the strongest features of the study is its comprehensive hormone analysis. Looking at hundreds of hormone-related compounds provided a much richer understanding than previous research.
However, there are also limitations. The study involved a relatively small number of participants and focused only on young men. It also did not directly measure long-term fertility outcomes.
The findings show that the relationship between cannabis and male reproductive health is far more complicated than many people assume. While the study challenges the idea that cannabis lowers testosterone, it does not prove that cannabis is harmless for fertility. The clinical meaning of these hormone changes remains uncertain.
Future studies will need to examine larger groups of people, follow participants over longer periods, and directly assess fertility outcomes. Until then, scientists say the effects of cannabis on male reproductive health remain an open question, with many important details still to be discovered.
The study was published in Communications Medicine.
Source: University of Geneva.
