In diabetic male rats, cannabis treatment caused a dose-dependent decrease in sperm motility at higher doses, and both cannabis and metformin negatively affected testosterone levels.
Diabetic men using cannabis, endocrinologists, and researchers studying cannabis effects on fertility.
Significant sperm motility decrease at 5 mg/kg THC dose
What the researchers found
Cannabis induced a significant concentration-dependent decrease in sperm motility at 5 mg/kg THC. Metformin increased sperm counts and lactate dehydrogenase activity. Both cannabis and metformin negatively affected testosterone concentrations.
Why it matters
Cannabis use is reportedly increasing among people with type 2 diabetes for pain and inflammation management. This study suggests cannabis may compound reproductive risks already associated with diabetes.
The numbers in context
35 rats. Cannabis 5 mg/kg THC: significant decrease in sperm motility (p=0.009). Metformin: increased sperm counts (p=0.035) and LDH activity (p=0.002). Both cannabis and metformin reduced testosterone.
How the study worked
Male Wistar rats (n=35) were fed a high-fat diet and injected with streptozotocin to create a type 2 diabetes model. Treatment groups received cannabis at THC concentrations of 1.25, 2.5, and 5 mg/kg and metformin (50 mg/kg) every other day for 10 weeks. Measured organ weight, testosterone, sperm count, motility, and enzyme activities.
What this study cannot tell us
Animal study in a chemically induced diabetes model. THC doses and frequency may not match human use patterns. Small sample (n=35 across all groups). Short duration relative to human chronic use.
How to read the evidence
Preliminary: small animal study with chemically induced diabetes model.
When this study was published
Published in 2022.
The bigger picture
Diabetic men already face reproductive challenges. If cannabis worsens sperm motility and testosterone in this population, it adds an important consideration for the growing number of diabetic patients turning to cannabis.
Questions still open
- Are these effects reversible after stopping cannabis? Would lower doses be safe for reproductive parameters? Do diabetic men who use cannabis show similar fertility effects?
Common questions
Did all cannabis doses affect sperm?
Did cannabis affect testosterone?
Should diabetic men avoid cannabis?
Read the original research
Cannabis and metformin on diabetic male Wistar rat sperm and reproductive organ parameters.
Journal of diabetes and metabolic disorders, 21(2), 1451-1458
Citation
van Losenoord, Wynand; Levendal, Ruby-Ann; Frost, Carminita Lara. (2022). Cannabis and metformin on diabetic male Wistar rat sperm and reproductive organ parameters.. Journal of diabetes and metabolic disorders, 21(2), 1451-1458. https://doi.org/10.1007/s40200-022-01079-z
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