Testosterone propionate was introduced in 1937 by Schering AG in Germany under the brand name Testoviron .  It was the first ester of testosterone to be introduced,  and was the major form of testosterone used medically before 1960.  In the 1950s, longer-acting testosterone esters like testosterone enanthate and testosterone cypionate were introduced and superseded testosterone propionate.  Although rarely used nowadays due to its short duration,  testosterone propionate remains medically available and is still marketed in the United States .  
Hmmmm interesting. Funny you mention it because I was taking gaba not too long ago and it was in a mixture with some other stuff. Anyways, I think it was causing me to wake up kind of uncoordinated and feeling just kind of weird. Dissociative I guess you could say, which makes sense because it’s related to the NMDA receptors somehow I think. It supposedly “can’t” cross the blood brain barrier, at least this is repeated despite the fact that it can and does, it’s just an unreliable mechanism in which it does. Low levels of gaba were insinuated to absorb more in the brain also. I didn’t have this issue as if I took the full 750 mg I felt very strange consistently and none of the other supplements in the mixture would seem to do this.