New Studies: How Marijuana Affects Sperm Health

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According to new research, marijuana might damage sperm in more than one way.  Not only can marijuana affect the size, shape and quality of men’s sperm (those parameters they measure on a semen analysis), but it can also impact the way they swim.


In the first of two new studies to show this, published in Human Reproduction, sperm samples from 1,970 men younger than age 30 were evaluated. They showed that men who had smoked marijuana in the last three months had negatively affected size and shape of their sperm.


The other study, done through Buffalo University, discovered that men who frequently smoked marijuana had considerably lower sperm count and less volume of seminal fluid.  Their sperm also had altered mechanics – they swam too fast too soon, which could cause them to burn-out before reaching an egg, thus impacting fertility potential. 


There are a number of chemicals implicated here: THC (tetrahydrocannabinol) is the main mood-altering chemical in marijuana.  Scientists believe that THC may impact how sperm swim, or it may block mechanisms designed to remove malfunctioning sperm.  THC has been shown to cause sperm to swim abnormally and lose their ability to attach to the egg (so fertilization cannot take place).


The studies did not examine whether sperm returns to normal after the men stop smoking marijuana, or how long that may take.  But one of the study directors did comment that men with borderline fertility could ‘tip the scales into infertility’ by smoking marijuana.


We know that it takes three months for a man to fully develop a sperm – so at least a period of 3 months marijuana-free would be required to increase the quality of sperm.  We also know a number of antioxidants and natural supplements can help with sperm quality and motility, I would combine these with a healthy diet and lifestyle regime, along with cessation of marijuana smoking, to increase fertility in a man with a history of use.


Both studies concluded that marijuana smoking contributes to infertility in men, and point to two different mechanisms as to why.  Bottom line – if you’re trying to conceive, stop smoking (anything).  You want to contribute the most optimal quality sperm to create the healthiest baby possible.


To learn more about how natural medicine and acupuncture can improve sperm quality and egg quality, come out to one of our natural fertility talks (next one is June 23rd, 2014).  Or call Acubalance at 604.678.8600 to schedule your free 15 minute consult with me or one of my colleagues!


In health,


Dr. Kali MacIsaac HBSc, ND

Naturopathic Doctor



A. A. Pacey, A. C. Povey, J.-A. Clyma, R. McNamee, H.D. Moore, H. Baillie, N.M. Cherry, and Participating Centres of Chaps-UK. Modifiable and non-modifiable risk factors for poor sperm morphology. Human Reproduction, June 2014 DOI: 10.1093/humrep/deu116


Baker, L. Sperm from marijuana smokers move too fast too early, impairing fertility, UB research shows.  University at Buffalo.