Although the link between marijuana and fertility is not straightforward—plenty of marijuana smokers get pregnant and get their partners pregnant—some research has demonstrated that marijuana use can negatively impact you, your partner, or the fertility of both of you.
Research suggests that marijuana can negatively affect female fertility in the following ways:
Furthermore, the effects of marijuana on fertility seem to accumulate over time. This means that although teenage girls who smoke marijuana are more likely to get pregnant, by the time a chronic marijuana smoking woman is in her mid-twenties, she may be more likely to experience a delay in getting pregnant.
And a 2019 study published in the journal Human Reproduction found that men who reported using cannabis had "significantly higher" sperm counts than men who reported never using cannabis.
If you’ve been confused by the facts surrounding the impact smoking weed can have on a man’s sperm count, you’re not alone. Here’s what experts are saying.
If the evidence seems stacked against marijuana use, there have also been some studies that negate marijuana's negative effects on fertility.
And a study published in the journal Epigenetics found that marijuana actually mutates DNA in sperm.
When it comes to research, most studies have concluded that marijuana is not good for sperm.
Another note: the method of marijuana consumption (i.e. smoking vs. edibles), is likely has the same impact on sperm.
While the research has gone both ways about marijuana's impact on sperm, doctors do not recommend men using marijuana.
A second major cohort study was done in 2017 by Thistle et al. 36 They used data on 1,577 American men using data from the 2011 to 2012 United States National Health and Nutrition Survey with several novel outcomes. No difference was observed in serum testosterone levels between ever and never users of marijuana. However, serum testosterone levels showed an inverse association with time since the last regular use of marijuana, and since the last marijuana use (p for trend 0.02 and <0.01, respectively). This indicated that recency rather than frequency of use may have the strongest relationship with serum testosterone levels. Additional large, population based samples are needed to clarify currently conflicting reported effects of cannabis on testosterone levels.
Cannabis binds to the CB1 and CB2 G protein-coupled cannabinoid receptors, which are the sites of action of endogenous endocannabinoids. 3 This signaling system is involved in a broad array of functions, including energy homeostasis, memory, movement and pain. 4 Exocannabinoids such as cannabis plant derived THC modulate cannabinoid receptors, likely interfering with the balance of downstream endogenous signaling pathways. 5
Medical cannabis has been used as an experimental remedy with varying degrees of success in a large number of disorders, including dementia, multiple sclerosis, Parkinson disease, social anxiety disorder, depression, tobacco use disorder and neuropathic pain. 7 Despite its growing popularity in the recreational and medical spheres, considerable research is still needed to understand the potential negative effects of marijuana. Particularly in the area of male fertility cannabis use has been linked to reproductive hormone changes, altered semen parameters and reductions in libido and sexual performance. 8 A detailed review of how marijuana affects male fertility at each point along the fertility axis is needed for clinicians to assess the potential risks that patients incur when using this substance.
Follicle Stimulating Hormone
We performed a literature search using PubMed®/MEDLINE® to identify relevant studies of the effects of cannabis on male fertility. Relevant studies were identified and reviewed.
Human studies have shown similar findings. In 20 chronic marijuana users who smoked marijuana at least 4 days per week for 6 months those who smoked 10 or more times per week had a significantly lower average ± SD sperm count than men who smoked 5 to 9 marijuana cigarettes per week (26.6 ± 7.3 vs 67.9 ± 6.3 million per ml, p <0.01). 12 This suggests an inverse relationship between marijuana use and sperm count. A Danish cohort study on marijuana use in 1,215 participants revealed similar changes. 13 Men who reported using marijuana more than once per week had a 28% lower sperm concentration and a 29% lower sperm count than men who had never used marijuana. In a study in which 16 chronic marijuana smokers were exposed to 4 weeks of high dose marijuana the time to a reduced sperm count was 5 to 6 weeks after initiating marijuana use. 14 In human and animal models cannabis has shown strong links to reduced sperm count and concentration which may be linked to arrested spermatogenesis. Future work is needed to elucidate causal mechanisms.
Cannabis, which has been used as an aphrodisiac since ancient times, was anecdotally described to enhance sexual performance and enjoyment. 42 In interview data on 800 chronic cannabis users collected by Kolodny et al 83% reported enhanced sexual pleasure while using cannabis. 43 A recent investigation by Androvicova et al validated these results by showing that cannabis intoxication increased activation of the right nucleus accumbens upon presentation of erotic stimuli, leading the authors to conclude that cannabis may help in the treatment of hypoactive sexual desire. 44
In a histological examination of the testes of mice exposed to cannabis Mandal and Das found fewer spermatogonia as well as basement membrane damage, scant cytoplasm and shrunken nuclei. 40 They also observed a reduction in seminiferous tubule diameter. Fortunately complete recovery of spermatogenesis and testicular cell function was seen 45 days after ceasing cannabis use, although testicular weight and seminiferous tubule size were not completely restored at that time. The authors speculated that testicular damage may be due to oxidative stress as a result of finding a significant decrease in antioxidant enzymes in affected testicles. This hypothesis was furthered by the work of Alagbonsi et al, who found that testicular damage induced by Cannabis sativa in rats was ameliorated by administering an antioxidant combination of melatonin and vitamin C. 41
With cannabis consumption on the rise and use prominent among males of reproductive age it is essential to understand the potential impact of cannabis on male fertility. We reviewed the literature regarding the effects of cannabis on male fertility.