A group of scientists from the French Institute of Health and Medical Research may have discovered the buzzkill in hormone form. It’s called Pregnenolone, and a new study suggests it may be released as a natural response to counteract the mental effects of marijuana. Researchers discovered the effect by administering massive doses of marijuana to lab rats. Monitoring the rats’ brains, they discovered elevated quantities of Pregnenolone being metabolized in response to the marijuana, which in turn reduced many of the mental effects of the drug. The same effect was replicated in human cell lines, indicating the human brain might show the same response.