The relationship between marijuana use and sexual activity is still not clear, but a large study now strongly suggests that regular cannabis use may increase sexual drive.

The link between marijuana and sex may be stronger than previously believed.

The findings come from a team of researchers led by Dr. Michael Eisenberg, who is an assistant professor of urology at Stanford University School of Medicine in California.

Dr. Andrew Sun, a resident in urology, is the first author of the paper. It was published in the Journal of Sexual Medicine.

Speaking about the motivation for the study, Dr. Eisenberg says, “Marijuana use is very common, but its large-scale use and association with sexual frequency hasn’t been studied much in a scientific way.”

In fact, the National Institute on Drug Abuse report that in 2015, 22.2 million people reported having used marijuana in the past month. But so far, research into the effects of marijuana on sexual satisfaction has yielded mixed results.

Experiments in rats found that the active compound in marijuana leads to fluctuations in sex drive. However, more recent studies suggest that endocannabinoids heighten sexual arousal in women, and that the drug enhances the sexual experience for both men and women.

In order to gain a better understanding of marijuana’s impact on sexual function, Drs. Eisenberg and Sun examined data from the National Survey of Family Growth (NSFG), which is a large-scale investigation conducted by the Centers for Disease Control and Prevention (CDC) on fertility, childbearing, family life, marriage, divorce, and men and women’s health.

The NSFG offers insight into the overall population of the United States and includes questions on the frequency of sexual intercourse and marijuana use.

More specifically, 28,176 heterosexual women and 22,943 heterosexual men were asked how many times they had had sex in the past 4 weeks, as well as how frequently they had used marijuana in the previous 12 months.

Participants were aged between 25 and 45, with women being 29.9 and men being 29.5 years old, on average. The researchers included data that had been gathered since 2002 as part of the NSFG.

The researchers adjusted for possible confounding factors such as the use of other drugs such as cocaine and alcohol.

Overall, 24.5 percent of the men and 14.5 percent of the women said that they had used marijuana in the previous 12 months.

The researchers noticed a correlation between how often people smoked marijuana and how often they had sex. More specifically, people who used marijuana had 20 percent more sex than those who did not, and this applied to both genders.

Women who refrained from having marijuana in the past year reported having had sex six times, on average, in the past 4 weeks, while for marijuana users, this number was 7.1.

Men who abstained from marijuana had sex 5.6 times in the past 4 weeks, while men who used marijuana daily reported an average number of 6.9 times.

The overall trend we saw applied to people of both sexes and all races, ages, education levels, income groups, and religions, every health status, whether they were married or single and whether or not they had kids.”

Dr. Michael Eisenberg

Despite these strong associations, Dr. Eisenberg cautions, this study does not prove causality. “It doesn’t say if you smoke more marijuana, you’ll have more sex,” he notes.

However, the overall message from this research is clear: “Frequent marijuana use doesn’t seem to impair sexual motivation or performance. If anything, it’s associated with increased coital frequency,” concludes Dr. Eisenberg.