A recent study from Harvard Medical School found that trace amounts of THC metabolites were detected in semen samples from frequent cannabis users. However, some samples did not test positive for substantive amounts of THC, which stumped researchers.
The study, published several weeks ago in Reproductive Physiology and Disease, was conducted by scientists at Harvard Medical School’s Center for Infertility and Reproductive Surgery. The study looked at semen samples from 12 “healthy” males who reported that they were “chronic and heavy users of inhaled cannabis.”
The study didn’t just look at THC and the primary THC metabolite, 11-OH-THC, in semen samples. It also assessed THC and metabolite levels in the subjects’ blood and urine. All urine samples contained detectable amounts of THC and 11-OH-THC, which confirmed that the subjects had consumed cannabis. Yet only two of the semen samples contained THC and metabolites above the reporting level of 0.5 ng/mL: at “0.97 nanograms per milliliter and 0.87 ng/mL,” Marijuana Moment reported.
Researchers were unsure why only two samples showed THC above the reporting level, in other words, at values high enough for chemists to reliably declare, There’s definitely weed in this seed. Possibly, THC does not readily enter the testes as it does urine or the blood. The small number of participants may have given the researchers a bad batch of samples, too.
In addition, if those ng/mL values look like a foreign language to you, they indicate that only incredibly tiny amounts of THC will pass the blood-testis barrier, a membrane that keeps contaminants in the bloodstream from damaging the little fellas swimming around inside of the testicles. Some studies suggest that cannabis use can impair sperm motility, though other studies have not found conclusive evidence that cannabis use actually affects virility or fertility. In other words, there’s little to no evidence that weed compromises a couple’s ability to naturally have babies.
Furthermore, less than 1.0 ng/mL of THC in semen is barely any THC at all. In most cases, blood samples will show 20 ng/mL of THC immediately after someone takes a rip off a pipe. And if you’re wondering if you can get your partner lit AF with a blowjob, that’s not happening either.
A nanogram is one millionth of a milligram, as in, it takes one million nanograms to make just one milligram. The standard minimum dose of THC that can cause heady effects (in low-tolerance users) is generally considered to be 5 milligrams. Twenty nanograms doesn’t even come close to this dose.
So, what’s the ultimate takeaway here? First, cops, courts, and employers won’t be asking for semen samples to see if you’ve been smoking weed. It’s much easier to test for cannabis use through saliva, blood, or urine samples for, uh, obvious reasons.
Second, this study provides some minute evidence that cannabis use could compromise sperm health or virility, but a lot more research is still needed regarding THC and baby-making.
And third, please don’t cite this study to try and elicit oral sex from a partner. That’s just downright skeezy.