Where does pharmaceutical testosterone come from?

I don’t know whether it is made from soy, but that is not why it is detectable.

The laboratory-created molecule and the body-created molecule differ in the ratios of C-12 and C-13 present. Mass spectrometry can detect these ratios, and scientists looking at that can determine whether the molecule was made by a person’s body or in a laboratory.

Also, many people who are dosing testosterone will have higher than average blood stream testosterone levels.

Thanks for clearing something up that was already cleared up in this thread 4 years ago, in post #13

Don’t forget the other reason. Most pharmaceutical and black market steroids actually have an some extra stuff. See this image. See the various stuff attached to the base testosterone molecule? Apparently, those extra molecules come off at some point, I think the liver removes them. And once they do, the testosterone is now active.

This allows someone to have high levels of testosterone all the time while only receiving 1-2 injections per week.

Anyways, the molecules of this drug with the extra ester hang around in someone’s bloodstream in small concentrations for months, and are a dead giveaway that someone has been using steroids. There’s not really any innocent explanation other than some improbable accident to have these specific molecules in your bloodstream.

Regarding the OP’s original question (5 years ago) about whether testosterone is “harvested” from men’s semen…
According to this paper, semen contains about 0.7 ng/mL of testosterone. A typical male ejaculation produces about 2-5 ml of semen, or at most about 3.5 ng of testosterone. A typical testosterone injection, as far as I can determine, contains 200 mg of testosterone. So to get enough for one injection from semen, they would have to obtain the semen from over 50 million ejaculations. It’s pretty obvious that that’s not happening.

You don’t remember Jr. High, do you?

OP here. Just so you know, I was joking about harvesting from humans. I kinda figured that wasn’t the way.

On the other hand, “Equivalent to 50 million ejaculations” would be an awesome marketing slogan.