• Posted June 1, 2026

Weed Linked To Higher Testosterone Levels In Young Men

Weed might boost young men’s testosterone levels, a new study says.

However, researchers say it’s not clear what this means for weed’s effect on male fertility.

Researchers found elevated testosterone levels among a small group of Swiss male weed users, compared to non-users of a similar age, researchers reported recently in the journal Communications Medicine.

“Our results show that cannabis use would lead to an increase of about 23% in testosterone in young men,’’ said senior researcher Serge Rudaz, a professor at the University of Geneva in Switzerland.

Analysis of the seven major sex hormones showed that this increase in testosterone is linked to the testicles, researchers said.

‘‘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. Androgens produced by the adrenal glands were not affected by this increase,” Rudaz said in a news release.

Cannabis thus appears to have a direct effect on the testicles, and more specifically on Leydig cells, which produce testosterone, researchers concluded.

But just because weed might boost testosterone does not rule out any potential negative effects it might have on fertility, they said.

“It is now essential to further investigate how this hormonal profile relates to semen quality in the context of cannabis exposure,” they wrote in their report.

Previous studies have indicated that weed might harm fertility by reducing sperm count, concentration and motility. These effects are thought to be linked to a network of receptors in the brain and reproductive organs that respond to cannabis compounds, known as the endocannabinoid system, they said in background notes.

For the new study, researchers took blood samples from 94 Swiss males drafted for military, half of whom were confirmed weed users and the other half non-users.

The team performed a deep-dive analysis of the sex hormones found in the men’s bloodstreams and found that weed was linked to increased testosterone levels.

It could be that cannabis promotes testosterone production in the testicles, researchers said.

However, “another possibility is reverse causality, that men with inherently higher testosterone could be more prone to cannabis use due to increased risk-taking behavior,” the team wrote.

The researchers also were able to identify two potential new biomarkers (or measurable characteristics in the body) of cannabis use: hydroxyprogesterone (11B-OHP4) and dihydroprogesterone (5B-DHP4).

“These are two metabolites derived from progesterone, another important sex hormone,” said lead investigator Mathieu Galmiche, a postdoctoral researcher at the Karolinska Institute in Stockholm.

“The increase in their concentration among users is so high that they could be used to monitor endocrine disruptions linked to regular cannabis exposure,” Galmiche said in the release. “Above all, this discovery should encourage the scientific community to expand studies to new hormones that have so far been overlooked, and which may also play a role in the male reproductive system.”

More information

The American Society for Reproductive Medicine has more on tobacco or marijuana use and infertility.

SOURCES: University of Geneva, news release, May 28, 2026; Communications Medicine, April 16, 2026