Does Marijuana Affect Testosterone Levels?

Most large human studies find that marijuana does not significantly lower testosterone, and a few even report slightly higher levels in users compared to non-users. This runs counter to a long-standing popular belief, largely built on early lab studies showing that cannabinoids can suppress testosterone production in isolated cells. The disconnect between what happens in a petri dish and what happens in a living person is a recurring theme in this research, and it makes the real-world picture more complicated than either “marijuana kills your T” or “marijuana has no hormonal effect at all.”

What Cell and Animal Studies Suggest

The idea that cannabis lowers testosterone traces back to laboratory work from the late 1970s and 1980s. In one classic experiment, researchers exposed rat testicular cells directly to various cannabinoids and found that even very low concentrations cut stimulated testosterone production by about half.¹ The cells responsible for making testosterone, called Leydig cells, appeared to have their protein synthesis disrupted as well. More recent cell-culture work has confirmed the basic finding: both THC and CBD reduce androgen production in steroidogenic cells in a dose-dependent way, with CBD appearing to interfere with a specific enzyme involved in the process.²

These findings are biologically plausible. The body’s own endocannabinoid system, which responds to compounds in cannabis, interacts directly with the hormonal axes that regulate testosterone production, including the signals sent from the brain to the testes.³ So the biological machinery for cannabinoids to influence testosterone clearly exists. The question is whether real-world cannabis use, at the doses and frequencies people actually consume it, produces the same effect that flooding isolated cells with cannabinoids does.

What Human Studies Actually Find

When researchers measure testosterone in actual cannabis users, the results look surprisingly different from the lab studies. A systematic review looking across the available human evidence on cannabis and male fertility described the effects on testosterone as “inconclusive.”⁴ That is a polite way of saying the studies go in different directions depending on how they were designed.

A large U.S. study using nationally representative data found essentially no difference in testosterone between men who had ever used marijuana and those who never had, after adjusting for age, weight, exercise, tobacco, alcohol, and other factors. The adjusted averages were nearly identical at about 3.7 ng/mL for both groups.⁵ If anything, current users had slightly higher testosterone than non-users, though the difference was small enough that it could easily be due to chance.

Another analysis using the same national dataset but with a different approach confirmed the pattern: after controlling for a long list of health and lifestyle factors, regular THC users had a small but statistically significant increase in testosterone compared to non-users.⁶ And a study of young men aged 18 to 23 who tested positive for THC in urine found that their testosterone and androstenedione levels were significantly higher than in THC-negative men.⁷ That study also noted a roughly 7% higher testosterone concentration in marijuana users from an earlier large Danish cohort, after adjusting for confounders.

Meanwhile, a study comparing frequent, moderate, and infrequent marijuana users against non-using controls found no significant effect of chronic use on testosterone in either men or women.⁸ The historical literature has gone back and forth on this for decades, with one case-report article noting that while one study found a dose-related effect of marijuana on testosterone, another study by a different group found no relationship at all.⁹

The overall pattern is that most well-controlled human studies either find no effect or find a slight increase. Almost none find the dramatic drop that cell studies would predict.

Recency of Use Matters More Than Amount

One of the more interesting patterns in the data involves when someone last used cannabis, rather than how much they use overall. In the large U.S. study, there was no dose-response relationship between testosterone and frequency of use, joints smoked per day, or total years of regular use.⁵ In other words, heavier users did not have lower testosterone than lighter users.

What did show a relationship was recency. Testosterone was inversely associated with time since last regular use, meaning that men who had used marijuana more recently tended to have slightly higher testosterone. Among younger men aged 18 to 29, this pattern was even stronger. This is the opposite of what you would expect if cannabis were steadily suppressing testosterone: in that case, more recent and heavier users should have the lowest levels, not the highest.

Why recent use might temporarily nudge testosterone upward is not well understood. One possibility is that an acute stress or arousal response triggered by THC causes a brief spike in certain hormones. Another is that younger men who use cannabis differ from non-users in ways that are hard to fully control for in a study, such as social behavior or sleep patterns. The finding is consistent across multiple analyses of the same dataset, but nobody has a clean mechanistic explanation for it yet.

Why the Lab and Real-Life Results Clash

The gap between cell-culture findings and human data is worth sitting with, because it comes up constantly in cannabis research. In the lab, you can drench Leydig cells in THC at specific concentrations and measure the output. In a living person, THC gets metabolized, distributed across tissues, and interacts with feedback loops that try to keep hormone levels stable. The body has robust compensatory mechanisms for maintaining testosterone within a range, including adjustments in signaling hormones from the brain. A short-term dip caused by cannabis could be corrected within hours by these feedback loops, so it never shows up in a single blood draw taken hours or days later.

There is also a timing problem. Most human studies measure testosterone at a single point, often long after the person’s last use. If cannabis causes a brief suppression that resolves quickly, cross-sectional studies would miss it entirely. The handful of controlled dosing studies that gave people marijuana in a lab and then tracked hormones over hours are quite old and had small sample sizes, making them difficult to generalize from.

Women and Testosterone

Women produce testosterone too, though at much lower levels, and it plays a role in energy, libido, and bone health. The evidence for cannabis affecting testosterone in women is even thinner than in men. One study comparing chronic cannabis users who used at least weekly with non-users found that cannabis use did not affect testosterone, cortisol, or other reproductive hormones, and breaking the analysis down by frequency of use did not change the result.¹⁰ The older study that grouped users by frequency also found no significant effect in women.⁸

That said, the research in women is especially sparse. Most of the larger studies focused exclusively on men, and the few studies that included women had small sample sizes. Cannabis may have effects on other aspects of female reproductive health, such as ovulation timing and menstrual regularity, but the specific testosterone question has barely been explored with adequately powered studies.

Adolescents and Puberty

If there is one group where the concern about cannabis and testosterone carries more weight, it is teenagers. The hormonal surges of puberty are orchestrated by a tightly regulated sequence of signaling events, and disrupting those signals during a sensitive window could have outsized effects compared to the same disruption in a fully mature adult.

The direct evidence here is thin but concerning. A systematic review on cannabis and pubertal outcomes described a case report of a 16-year-old boy who was a heavy cannabis smoker and had delayed puberty along with low testosterone levels. When he stopped using cannabis, his testosterone rose, his growth accelerated, and pubertal development progressed.¹¹ A single case report is far from conclusive, but it aligns with the biological plausibility from cell studies: if cannabinoids interfere with the signaling chain that triggers testosterone production, a developing body with less hormonal reserve might be more vulnerable than an adult whose system has fully matured.

No large, controlled study has been done on this topic in adolescents for obvious ethical reasons, so the evidence sits at the level of case reports and animal models. For parents and teenagers, this is arguably the area where the precautionary principle makes the most sense, since the stakes of disrupting pubertal timing are higher than the stakes of a brief, reversible hormonal blip in an adult man.

Synthetic Cannabinoids Are a Different Story

Products sold as “synthetic marijuana” or “spice” contain lab-made compounds that bind to the same receptors as THC but often with far greater potency and different pharmacological profiles. These should not be conflated with plant-derived cannabis when thinking about hormonal effects. Research on the synthetic cannabinoid AB-FUBINACA found that it caused a dose-dependent drop in testosterone in animal models, without corresponding changes in the brain-derived hormones that normally regulate testosterone production.¹² This suggests the compound was acting directly on the testes rather than through the usual brain-to-gonad signaling pathway.

Synthetic cannabinoids also caused testicular toxicity in the same study, with structural damage to the tissue. The profile of harm from synthetic cannabinoids is generally more severe and more unpredictable than from THC, and the testosterone findings fit that pattern. If you are using synthetic products and worried about hormonal effects, the evidence gives you considerably more reason for concern than if you are using plant-based cannabis.

CBD Specifically

As CBD products have become ubiquitous, a natural follow-up question is whether CBD alone affects testosterone. The cell-culture data suggests it can: in one study, CBD reduced androgen production in a dose-dependent manner, similar to THC, and additionally appeared to interfere with a specific enzyme in the steroid-synthesis pathway that THC did not affect.² This is a somewhat surprising finding given that CBD is often marketed as the “non-psychoactive” and by implication “harmless” component of cannabis.

However, the same caveat from THC research applies here with even more force: no large human study has specifically measured testosterone changes from CBD-only products. The concentrations used in cell studies may not correspond to what reaches the testes after you take a CBD gummy or use a tincture. Until someone runs that human study, the cell data is a signal worth tracking rather than something to panic about.

Why This Research Is So Hard to Do Well

Almost every study on cannabis and testosterone faces the same cluster of design challenges, which partly explains why results vary so much. The young-men study that found higher testosterone in THC-positive participants noted that while they could control for age, BMI, time of blood draw, and tobacco use, they could not account for diet, alcohol intake, sleep quality, or stress levels.⁷ Any of those unmeasured variables could push testosterone in one direction or another and create a false impression of a cannabis effect.

Testosterone also fluctuates throughout the day, dropping through the afternoon and spiking during sleep. A study that draws blood at a standardized morning time point will get different results from one with more variable timing. Self-reported cannabis use is another weak link: people underreport use, misremember frequency, and vary wildly in the potency of what they consume. A joint from 1991 contained substantially less THC than one from today, which makes comparing older and newer studies hazardous. Even studies that use urine testing for THC metabolites can only confirm recent exposure, not the pattern of use over months or years.

The gold standard would be a randomized trial where some men are assigned to use cannabis and others a placebo, with testosterone measured repeatedly over months. These trials are extraordinarily rare, partly because of regulatory barriers around cannabis research and partly because the hormonal effects, if they exist at all, appear to be subtle enough that you would need a large trial to detect them reliably. The result is that most of the evidence comes from cross-sectional studies, which can show associations but cannot prove that cannabis caused a change in testosterone rather than the other way around, or that both are driven by something else entirely.

Gynecomastia and Other Hormonal Concerns

One persistent claim is that marijuana causes gynecomastia, or the development of breast tissue in men, which is sometimes linked to low testosterone or elevated estrogen. This idea has been floating around since the 1970s, but the evidence for it is remarkably weak. A review of the topic noted that researchers were unable to confirm a relationship between cannabis use and gynecomastia even in the study that found a dose-related effect on testosterone.⁹ The case reports that do exist tend to involve dronabinol, a synthetic form of THC used as a prescription medication, rather than smoked cannabis, and they remain anecdotal rather than supported by controlled data.

Similarly, concerns about cannabis causing infertility through testosterone suppression are not well supported by the hormone data in humans, though cannabis may affect sperm quality through other mechanisms that do not involve testosterone at all. The systematic review on cannabis and male fertility noted that while testosterone effects were inconclusive, there was evidence of lowered luteinizing hormone, the brain signal that tells the testes to produce testosterone.⁴ A drop in this signaling hormone without a corresponding drop in testosterone could mean the body is compensating, or it could mean the timing of measurement is missing a transient effect. Either way, the fertility conversation is broader than testosterone alone, and focusing only on testosterone levels may miss other ways cannabis affects reproductive function.

1
PubMed. Effects of cannabinoids on testosterone and protein synthesis in rat testis Leydig cells in vitro
2
PubMed. Tetrahydrocannabinol (THC) and cannabidiol (CBD) inhibit androgen biosynthesis in H295R cells
3
PubMed Central. Endocannabinoids and the Endocrine System in Health and Disease
4
PubMed Central. Cannabis and Male Fertility: A Systematic Review
5
PubMed Central. Marijuana use and serum testosterone concentrations among U.S. males
6
PubMed. The effect of tetrahydrocannabinol on testosterone among men in the United States
7
PubMed Central. Cannabis consumption is associated with altered steroid metabolism in young men
8
PubMed. Effects of chronic marijuana use on testosterone, luteinizing hormone, follicle stimulating hormone, prolactin and cortisol in men and women
9
The American Journal of Medicine. Dronabinol-induced Gynecomastia
10
PubMed Central. The Effects of Cannabis on Female Reproductive Health Across the Life Course
11
PubMed Central. The effect of cannabis exposure on pubertal outcomes: a systematic review
12
PubMed Central. Synthetic Cannabinoid AB-FUBINACA Negatively Impacted the Male Fertility and Induced Testicular Toxicity