Marijuana is a drug derived from the hemp plant Cannabis sativa or Cannabis indica. Its main psychoactive component is tetrahydrocannabinol (THC), which is linked to altered sensual perception, mood changes and impaired body movements. Other components of cannabis (cannabinoids) have unique pharmacologic effects without the psychoactive effects of THC.
There are only a few conditions where cannabinoids have been proved to be useful and approved by the US Food and Drug Administration (FDA). These include:
Chemotherapy-induced nausea and vomiting
Appetite stimulation in conditions that cause weight loss, such as AIDS
Specific types of seizure disorders in children
Other indications that have been less well studied include chronic pain, muscle spasticity from multiple sclerosis, Parkinson's disease, post-traumatic stress disorder (PTSD) and Tourette syndrome.
As of August 2019, 33 states and the District of Columbia have initiated policies allowing the use of cannabis or cannabinoids for the management of specific medical conditions. Eight states have now legalized marijuana for recreational use. The federal government, however, still classifies cannabis as illegal, complicating its medical use and research into its effectiveness for the various conditions its use is supposed to benefit. A lot of the research is based on animal and laboratory studies.
The negative effects of acute cannabis use are well documented. These include impaired learning, memory, attention and motor co-ordination (making driving dangerous). It can affect judgement leading to risky decisions that one would not otherwise make. Chronic use is associated with increased risk of psychiatric illness (e.g. schizophrenia) and addiction. Chronic use can lead to cannabis use disorder (CUD, near-daily use of more than one-eighth of an ounce of cannabis per week) and contributes to impairment in work, school and relationships.
There is a decrease in sperm count and concentration in both human and animal studies. A study in 20 chronic marijuana users who smoked marijuana at least 4 days per week for 6 months and those who smoked 10 or more times per week had a significantly lower average sperm count than men who smoked 5 to 9 marijuana cigarettes per week.
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. It takes 5 to 6 weeks of high dose marijuana use for the sperm count and concentration to decrease.
There is extensive evidence showing cannabis having a negative effect on sperm motility. This is seen with both medicinal and recreational use. The effect on motility is seen after 4 weeks of high dose marijuana.
Cannabis use also decreases sperm viability and its ability to fertilize an egg. Male hormones are also negatively impacted by marijuana. Animal studies have shown that testosterone levels are suppressed with chronic marijuana use. Animal studies have shown a reduction in size of the testes with marijuana use.
Cannabis has been used as an aphrodisiac since ancient times and has been described to enhance sexual performance and enjoyment. Recent studies have confirmed that its short-term use does increase sexual desire. However, chronic use of marijuana is associated with erectile dysfunction.
In conclusion, chronic marijuana use has a negative impact on male fertility. It results in lowering of both sperm count and concentration, motility as well as shape of the sperm. Testosterone levels are reduced and there is a decrease in testicular volume with chronic marijuana use. Short-term use of marijuana may enhance sexual performance and enjoyment. Chronic use, however, may cause erectile dysfunction.
At InVia Fertility Specialists, our board certified physicians are available for consultation at our four locations in the Chicagoland area. We advise our patients to not use marijuana because of its negative effects.
Dr. Karande is Board Certified in the specialty of Obstetrics and Gynecology as well as the subspecialty of Reproductive Endocrinology and Infertility. He is a Fellow of the American College of Obstetricians and Gynecologists and Member of the American Society for Reproductive Medicine.