Does Weed Lower Testosterone? The Evidence Is More Complicated Than You Think

Cannabis is the most widely used illicit substance worldwide, and as legalization expands, more men are asking a reasonable question: what does it do to testosterone? The internet offers two opposing narratives. One claims weed destroys your testosterone. The other insists it has no effect whatsoever. The actual evidence is messier than either, and a precise number such as “15 to 20 percent lower” is not backed by the studies we reviewed.

The short version: the evidence on testosterone is inconsistent, while the evidence on sperm quality is more consistent. Some studies suggest lower hormone levels, others find no difference or even higher testosterone in users. This article is educational information, not medical advice.

The Endocannabinoid System and Your Hormones

Your body produces its own cannabinoids, called endocannabinoids, that act on CB1 and CB2 receptors. Cannabinoid receptors are present at each level of the hypothalamus-pituitary-gonadotropic axis, the feedback loop that controls testosterone production, which is why researchers have long asked whether cannabis could affect it.^[5]

The proposed pathway is that THC, the main psychoactive compound, could reduce GnRH signaling and therefore luteinizing hormone (LH) output from the pituitary, which in turn would reduce the signal for the testes to make testosterone. This is a hypothesis. The review of cannabis and male fertility did report lowered LH in studies of hormonal changes, but found testosterone effects inconclusive.^[1]

What the Human Studies Actually Show

An early study published in 1974 reported depressed plasma testosterone in men after chronic intensive marijuana use, which helped start the idea.^[6] Since then, results have not lined up neatly:

• In the Danish study of 1,215 young men, the authors reported that marijuana smokers had higher levels of testosterone, within the same range as cigarette smokers.^[2]
• In a Swiss cohort of young men, androgens, estradiol and SHBG were all higher in cannabis users, particularly chronic, recent and CBD-positive consumers, while gonadotropin levels did not differ significantly.^[5]
• In a large claims-database analysis, a cannabis abuse or dependence diagnosis was associated with a higher risk of a testosterone deficiency diagnosis (defined as a level below 300 ng/dL). The absolute rates were small and the authors list the inability to assess dose and the use of diagnosis codes as proxies for use as limitations.^[3]
• A systematic review concluded that hormonal studies suggest inconclusive effects on testosterone.^[1]

The honest reading is that we cannot say how much, or even reliably whether, cannabis lowers testosterone in a typical user. Most of these are observational studies, so differences between users and non-users (sleep, body weight, alcohol use, other drugs, timing of the blood draw) could explain the results either way. Frequency of use appears to matter in the sperm data, but we found no solid human data defining a testosterone effect for occasional versus daily use.

Is Any Effect Reversible?

You will often see claims that testosterone normalizes within weeks of quitting. We could not find solid human data to support a specific recovery timeline for testosterone, and given how inconsistent the evidence on testosterone is, that is not surprising. The authors of the fertility review called for further studies to validate the findings and to understand the effects over time.^[1]

THC vs. CBD: Do Not Assume CBD Is Neutral

Cannabis contains many cannabinoids, but the two most discussed are THC and CBD (cannabidiol). Because CBD is non-intoxicating, it is often assumed to be harmless for hormones. The research does not support that assumption. A literature review of 32 studies (cells, animals and some human data) found that CBD exposure was associated with reduced testis size, fewer germ and Sertoli cells, lower fertilization rates and lower plasma hormone concentrations in mammals, and the authors concluded that CBD has negative effects on the male reproductive system, while stressing that knowledge is still limited and that most treatment periods were acute or subacute.^[4]

Human data are different from animal data, and the Swiss cohort found higher androgen levels in CBD-positive users.^[5] The takeaway is uncertainty in both directions. There are no controlled human trials we could find showing that CBD products raise or lower testosterone in healthy men, so claims either way are premature.

Sperm Quality: A More Consistent Finding

The evidence on sperm is firmer than the evidence on testosterone. A systematic review reported that the strongest evidence of cannabis-induced changes in male fertility is in semen parameters, with research supporting a role for cannabis in reducing sperm count and concentration, causing morphology abnormalities, and reducing motility and viability.^[1] A separate systematic review of 91 articles concluded that, using semen parameters as a surrogate, cannabinoids likely play an inhibitory role in male fertility.^[7] The Danish study above found a 28 percent lower sperm concentration with regular use.^[2]

For men who are trying to conceive or planning to, the sperm data may be more relevant than the testosterone data. The Journal of Urology review recommends that clinicians consider cannabis use as a possible component of a male infertility workup.^[1]

Confounding Factors: What Else Changes With Cannabis Use

Separating direct hormonal effects of cannabis from lifestyle patterns that sometimes accompany regular use is difficult. Sleep, body weight, alcohol use and other recreational drugs each have their own associations with testosterone, and the Danish study found that combining marijuana use more than once a week with other recreational drugs was linked to a 52 percent lower sperm concentration.^[2] As one example of how much sleep alone can matter, a small experiment in 10 healthy young men found that a week of 5-hour sleep opportunities lowered daytime testosterone by 10 to 15 percent.^[8] Our guides to sleep and testosterone, body fat and testosterone and alcohol and testosterone cover these factors.

If You Use Cannabis

There is no evidence-based amount or schedule of cannabis use that is proven safe for male hormones, so we are not going to invent one. Practical points that follow from the research above:

• If you are trying to conceive, talk to a doctor about cannabis use, since sperm parameters are where the evidence is strongest.^[1]
• If you have symptoms such as low libido, erectile difficulties or fatigue, mention your cannabis use to your doctor, who can test testosterone properly with a fasting morning blood draw and consider other causes.
• Protect the basics that are better established: sleep, physical activity and body weight.
• If you feel your use is hard to control, a doctor or local support service can help.

The Bottom Line

The relationship between cannabis and testosterone is unsettled. Reviews describe the testosterone data as inconclusive, some large studies of users found higher rather than lower testosterone, and other analyses found an association with testosterone deficiency diagnoses.^[1,2,3] The sperm quality evidence is more consistent.^[1] Anyone who tells you cannabis definitely lowers testosterone by a set percentage, or that it has no effect at all, is going further than the evidence goes.

How Thrive Helps

Thrive helps you track the lifestyle factors that are better established for hormonal health, including sleep, training consistency and daily habit streaks. Thrive is a wellness app, not a medical device, and it does not diagnose or treat any condition. Try Thrive free.