# Where does pharmaceutical testosterone come from? **URL:** \ **Category:** Factual Questions\ **Created:** [October 6, 2012, 5:24am UTC](https://boards.straightdope.com/t/where-does-pharmaceutical-testosterone-come-from/636880 "2012-10-06T05:24:57Z")\ **Posts on this page:** 7\ **Page:** 2
**Author:** ![blamtastical](https://avatars.discourse-cdn.com/v4/letter/b/6de8d8/32.png) [@blamtastical](https://boards.straightdope.com/u/blamtastical)\ **Post date:** [February 13, 2018, 8:05am UTC](https://boards.straightdope.com/t/where-does-pharmaceutical-testosterone-come-from/636880/21 "2018-02-13T08:05:09Z")
> [@R.P.McMurphy](#): > > I may be totally wrong but I seem to have read that it get synthesized from soy. That is the reason that it can be detected in drug tests. It’s very similar but not exactly the same as human produced testosterone. Now, CMIIW. 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. ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [February 14, 2018, 6:24pm UTC](https://boards.straightdope.com/t/where-does-pharmaceutical-testosterone-come-from/636880/22 "2018-02-14T18:24:41Z")
> [@blamtastical](#): > > 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… > [@buddy431](#): > > It’s typically from wild yams or soy. Synthetic testosterone is chemically identical to that produced by the body. The way they tell it apart (for drug testing purposes) is from the isotopic composition, specifically the [carbon-12/carbon-13 ratio](http://pipeline.corante.com/archives/2006/08/01/testosterone_carbon_isotopes_and_floyd_landis.php). > > The difference in the isotope ratio is pretty darn small (carbon-13 makes up only about 1% of carbon atoms anyway, and then you get a small variation on that 1%), but can be measured with a modern mass spectrometer. You wouldn’t expect any difference physiologically from the testosterone itself (although other components, concentration, etc. etc. could affect the physiological response) ---
**Author:** ![SamuelA](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@SamuelA](https://boards.straightdope.com/u/SamuelA)\ **Post date:** [February 14, 2018, 8:09pm UTC](https://boards.straightdope.com/t/where-does-pharmaceutical-testosterone-come-from/636880/23 "2018-02-14T20:09:14Z")
> [@blamtastical](#): > > 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. Don’t forget the other reason. Most pharmaceutical and black market steroids actually have an some extra stuff. See [this image](http://www.isteroids.com/steroid-esters/steroids-images/orally-active-steroids-4.jpeg). 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. ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [February 15, 2018, 12:20am UTC](https://boards.straightdope.com/t/where-does-pharmaceutical-testosterone-come-from/636880/24 "2018-02-15T00:20:42Z")
Regarding the OP’s original question (5 years ago) about whether testosterone is “harvested” from men’s semen… According to [this paper](https://www.ncbi.nlm.nih.gov/pubmed/1030919), 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. ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [February 15, 2018, 12:40am UTC](https://boards.straightdope.com/t/where-does-pharmaceutical-testosterone-come-from/636880/25 "2018-02-15T00:40:47Z")
> [@markn\_1](#): > > Regarding the OP’s original question (5 years ago) about whether testosterone is “harvested” from men’s semen… > According to [this paper](https://www.ncbi.nlm.nih.gov/pubmed/1030919), 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? ---
**Author:** ![obbn](https://avatars.discourse-cdn.com/v4/letter/o/d6d6ee/32.png) [@obbn](https://boards.straightdope.com/u/obbn)\ **Post date:** [February 15, 2018, 2:14am UTC](https://boards.straightdope.com/t/where-does-pharmaceutical-testosterone-come-from/636880/26 "2018-02-15T02:14:23Z")
OP here. Just so you know, I was joking about harvesting from humans. I kinda figured that wasn’t the way. ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [February 15, 2018, 2:56pm UTC](https://boards.straightdope.com/t/where-does-pharmaceutical-testosterone-come-from/636880/27 "2018-02-15T14:56:19Z")
On the other hand, “Equivalent to 50 million ejaculations” would be an awesome marketing slogan. [Previous page](https://boards.straightdope.com/t/where-does-pharmaceutical-testosterone-come-from/636880.md?page=1)