Modified testosterone metabolites can cross the blood-brain barrier and act as GABA agonists.

“the blood-brain barrier, especially if it's 5-alpha and 3-alpha reduced, so it's modified a little bit, then it is both a GABA agonist, which helps sleep just like GABA does, gamma-amino butyric acid, the main inhibitory neurotransmitter of which lots of things work on, alcohol works on GABA as well. Gabapentin also works on GABA. Migraine medicines, many of them work on GABA. Benzodiazepines, and also non-benzos. So an example of a benzo would be Xanax. An example of a non benzo would be Ambien. So those all work on GABA.”