Marijuana use and “gardening” has exploded in the United States, but only a handful of states still allow public access to marijuana. As of 2023, 38 states allow marijuana for medical use, and 24 states have legalized marijuana for recreational use.
Marijuana (or weed) is the most commonly used drug in the U.S. According to the Centers for Disease Control and Prevention (CDC), about 18% of Americans used marijuana at least once in 2019.
As cannabis becomes more accessible, research on its health benefits and risks is also on the rise. With regards to fertility, researchers have looked at both how cannabis affects female fertility, and how cannabis affects male fertility, sperm, and sperm health.
So, does smoking marijuana affect sperm? Learn how cannabis affects sperm count, motility, DNA, and fertility.
Marijuana’s effects on sperm count and motility
“Tetrahydrocannabinol (THC), the active compound in marijuana, binds to receptors in various glands and tissues involved in sperm production,” says Matthias Hofer, M.D., a urologist in San Antonio, Texas. “These receptors are located in the hypothalamus and pituitary gland, and they decrease the production of hormones needed for sperm production.”
When it comes to research, most studies have concluded that marijuana is bad for sperm.
“There are numerous experimental studies showing that marijuana has adverse effects on sperm. Surprisingly, very few studies have been done in humans, but all of them show that marijuana use reduces sperm concentration, sperm motility (ability to swim), or both,” said Doron Stember, MD, associate professor of urology at the Icahn School of Medicine at Mount Sinai.
The main reason no studies have been done on humans is because marijuana is classified as a Schedule I drug on the federal drug schedule, even though it is legal in most states. Its Schedule I classification means that researchers must meet strict federal requirements, including registering with the U.S. Drug Enforcement Administration (DEA), undergoing background checks, and tracking and destroying the drug.
Still, some research does exist. For example, a 2015 study evaluated the association between cannabis use and reproductive hormones and semen quality. Among 1,215 Danish participants aged 18 to 28, researchers found that those who smoked cannabis regularly, at least once a week, were associated with:
- Sperm concentration less than 28%
- Total sperm count decreased by 29%
- Combining marijuana with other recreational drugs reduces sperm concentration by 52%
- When combined with other recreational drugs, it reduces total sperm count by 55%
Marijuana’s effects on sperm DNA
Several studies have shown that smoking marijuana can not only affect sperm count and motility, but can also fundamentally change sperm.
A study published in the journal Epigenetics found that cannabis does indeed mutate sperm DNA. The study, published in 2018, was the first to report disruptions to sperm DNA in cannabis users. Researchers suspect that these changes may be due to the THC component of cannabis.
The researchers say the increased risk of exposure is due to two important trends affecting cannabis use.
- Fewer and fewer young people believe that regular marijuana use is harmful.
- Cannabis potency has increased dramatically over the decades (the ratio of THC to cannabidiol increased from approximately 14:1 to approximately 80:1 between 1995 and 2014).
Marijuana’s effects on sexual function
An older study from 2010 found that marijuana use reduced men’s orgasmic ability and caused them to orgasm too soon or too late, but more recent studies have found the opposite.
For example, a 2023 study of 811 participants of all genders and sexual orientations found that people of all genders felt that cannabis improved their sexual function and satisfaction, as well as increased the intensity of their orgasms.
Additionally, some studies have denied that cannabis has any adverse effects on fertility.
Marijuana’s effects on fertility
While studies have shown that inappropriate cannabis use can negatively affect sperm, there are limited studies evaluating moderate consumption. A 2019 study looked at how smoking marijuana affects sperm by comparing men who had smoked marijuana with those who had never smoked marijuana.
The researchers were surprised to find that sperm concentrations in men who had ever used marijuana were significantly higher than in men who had never used marijuana, and they found no significant differences in sperm concentrations between current and past users.
Another 2017 study of 1,577 men found that marijuana use was associated with, but did not necessarily cause, higher testosterone levels. The researchers noted that the time of a subject’s last cannabis use had a greater impact on testosterone levels than the duration or frequency of their cannabis use.
This may make it difficult to give clear answers about cannabis and fertility, but doctors believe more research is needed.
“There is a large body of scientific evidence that THC can negatively affect fertility at various levels, but it is important to note that some of these studies are limited by small patient numbers and some have shown conflicting results,” said Dr. Hofer. “Clinical trials — the highest quality studies that will produce the most reliable results — have yet to be conducted, and we will learn more.”
Does the method of consumption matter?
How you consume cannabis or THC (smoking vs. edibles, for example) may not affect sperm differently. “Reabsorption of THC occurs after inhalation and after ingestion, so we would expect the effects on sperm to be similar,” says Dr. Hofer. But, says Dr. Stember, “there have been no studies comparing the effects of smoking, vaping, or eating cannabis.”
So if you smoke marijuana and are having trouble getting pregnant, your marijuana use may not be the only cause of your infertility.
“Fertility is affected by many factors, THC is only one of them,” says Dr. Hofer. “While there is some evidence that THC may affect sperm count and quality and overall fertility (low sperm counts can be enough to conceive), recent studies suggest that fertility does not appear to differ between cannabis users and non-users.”
The study Hoffer was referring to was a 2018 study that evaluated the association between cannabis use in men and women and the chances of getting pregnant during their menstrual cycle. The study found little overall association between marijuana use and fertility.
The risks and benefits of smoking marijuana
So, does smoking marijuana affect sperm? Should people trying to conceive stop using cannabis?
While there has been a lot of research into the effects of cannabis on sperm , medical professionals generally do not recommend its use. In addition to potential fertility concerns, the CDC lists the following possible adverse health effects of marijuana:
- Poisoning
- Negative effects on brain health (especially memory, learning ability, attention, decision-making, coordination, emotions, and reaction time)
- Drinking and driving
- Cardiovascular effects (increased heart rate and blood pressure immediately after use, increasing the risk of stroke, heart disease, and vascular disease)
- Lung Damage from Marijuana Smoking
- Increased risk of mental health problems
- Children mistake plant-based foods for candy and eat them
- Especially when taken in excess with food
- Passive smoking for people around you
However, the CDC also notes known potential benefits, such as reducing the side effects of cancer and cancer treatments. Although evidence of cannabis’s pain-treating abilities is limited, many people use it to relieve chronic pain.
Key Points
“Based on current evidence, in the absence of other factors associated with reduced sperm count, it may be advisable to discontinue THC use if you are planning to conceive, even if your sperm count may be adequate,” says Dr. Hofer. Dr. Stember agrees, saying that people concerned about fertility should stop or reduce their cannabis use. The more marijuana you use, the more likely you are to develop sperm problems.
