T Nation

Can a Smart Person Explain This to Me?


Can anyone explain to me why and how this would stop sperm production and why it would also lower libido?


New male contraceptive injection appears effective

Updated Tue. May. 5 2009 1:11 PM ET

CTV.ca News Staff

An injection for men appears to be just as effective at preventing pregnancy as the birth control pill, finds new research that could revolutionize contraception.

In testing in China, only one man in 100 fathered a child while on the injections, the study in the Journal of Clinical Endocrinology & Metabolism reports.

The contraceptive is a form of testosterone that is injected into the buttocks once a month. It works by temporarily blocking sperm production.

Chinese researchers injected 1,045 healthy Chinese men aged 20 to 45 years with a 500 mg of testosterone undecanoate in oil, once a month for 24 months. All of the study participants had had at least one child and all their female partners, aged 18 and 38 years, also had normal reproductive function.

They found the contraceptive was almost 99 per cent effective, with a failure rate of only 1.1 per 100 men.

There were no serious side effected reported in any of the men, unlike previous studies on hormonal male contraceptive. Some of the side effects of those formulations have been mood swings and a lowered sex drive.

In all but two of the men in this study, reproductive function returned to normal range within six months of stopping the injections.

"For couples who cannot, or prefer not to use only female-oriented contraception, options have been limited to vasectomy, condom and withdrawal," said Dr. Yi-Qun Gu, of the National Research Institute for Family Planning in Beijing, China.

"Our study shows a male hormonal contraceptive regimen may be a potential, novel and workable alternative."

It should be noted though that almost a third of the 1,045 men in the 30-month trial did not complete the study. No reason was given.

Gu says while the results of this trial are encouraging, more long-term testing needs to be done on the safety of the regimen, with a focus on cardiovascular, prostate and behavioral safety.

Gu said if further tests proved successful, the treatment could become widely available in five years.


Because it suppresses the Hypothalamus-Pituitary-Testicular Axis (HPTA)

Simply put, the HPTA is 2 areas of the brain and the balls - the 3 components that secrete the necessary chemicals to A) Produce Testosterone and B) Produce Sperm... among other hormones both primarily (Prolactin) and secondarily (DHT).

If this (the HPTA) is inhibited by external sources of Test'rone, then the hormones that tell the testes to make sperm and testosterone cease to be produced.

The reason libido drops when trying to suppress sperm production is the resulting drop in testosterone due to them both being signalled from the same part of the brain - the Pituitary, HOWEVER it seems that 500mg of test undecanoate (the longest ester of test available) per month is enough for TRT which 'replaces' the missing testosterone which was once produced naturally.

This however is info that they have had for years, (all men on TRT do the same exact thing except with weekly or fortnightly injections of a shorter estered Test'rone, instead of monthly) and using external androgens to create a male contraceptive is nothing new - i am quite surprised that THEY are surprised by this, as to me this is nothing short of what we talk about here everyday!

I am surprised it has taken them so long to try the undecanoate ester and a dose that is equivalent to TRT dose to keep libido high as well as suppress. It cant be as cut and dried as they have reported to the papers/media - as i mentioned, this isnt much of a breakthrough otherwise.

I was under the impression that they were trying to avoid the resulting testosterone decreases by trying to JUST inhibit the secretion of Follicle Stimulating Hormone (FSH) and not Leutenizing Hormone (LH) - as is the case with normal androgen supplementation for contraceptive purposes.

I am sure there is more to it for this reason... but maybe they gave up trying to do it right, and are continuing with the second best option - thus the introduction to the media with the 'breakthrough'.



You have misread the article in thinking it said that this treatment lowered libido. Rather, it said that other, differing treatments have done so.


Bill, on this topic - do you know the details on some of the other trials?
As i mentioned in my post - i thought that exogenous testosterone mediated suppression has been researched for years as the male contraceptive and they were not happy with it due to all the possible sides; suppression of natural T, prostate enlargement, and the risk of TRT being needed after long periods.

I was sure i read about this being done years ago and i assumed they were looking for a different kind of androgenic suppression - as this is no different to TRT! Same dose, just different ester - are people that naive?




Why do they keep saying in the next 5 years. I think I seen this 5 years ago with maybe test. Just cause they tryed a new ester this is suppose to be new. I just don't get it. I read some of the comments by joe public and they were amazed this was out there. Gawd we have a long way to go about peoples knowledge of these drugs.


No, I don't know what the other hormonal treatments that decreased libido were, but being the Chicoms, what would have stopped them from trying, for example, progestin-based drugs? As an example only.


Yes I did misread it. I guess it was too early this morning.


Easy enough to do, for sure. I hate when I do that :slight_smile:


So basically this is a mild form of taking steroids and apparently the medical community is ok with that now cause a huge pharmacuetical company will get rich off it?


Read TRT.


But just think how much easier it will be to get whatever ester they decide on.


Oh for sure don't get me wrong!

I was coming from the angle that up until now all we ever hear is steroids are bad, steroids will kill you.......... but now they're ok because we stand to make a profit!


I don't think anyone outside of true for-life TRT guys are going to want to deal with the undecanoate ester. Waaaaaay too long.


I don't get how this is 99% effective. I have always heard that the best success rate that could be derived from most past trials of testosterone based "male birth control" ended up resulting in success rates at around 80% or less. How many of you guys know someone who got their wife or girlfriend pregnant in the middle of a heavy cycle? Hell, my child was conceived in the middle of a heavy cycle!


You're just a man though! = )


we all know that everyone reacts slightly different to all drugs. this will end up being no different. doses for female hormonal contraceptives vary. back in the 60's doses were much more than they use now. I forsee this being just the same it will just take some time.


I'd guess either or both of two possibilities:

1) Ethnic difference
2) Chinese culture has an incompatibility with sound science in that being in agreement with the leader and proving the leader right are pretty much moral and/or social imperatives.

There are any number of outcomes in Chinese studies that are hard or impossible to account for in any way other than the more junior scientists and researchers in the group being bound and determined to prove the group leader right.

I agree, the claimed very high success rate particularly on so modest a dose makes little sense, barring either of the above 2 explanations (or both.)


Ha ha! Good point. Your guess is certainly a lot easier for me to swallow than those purported results.


A virile man, my friend! :wink:


Thanks for the info Cortes. I've got friends asking me about this and i know very little about steroids so if possible can you explain further what you mean by undecanoate ester and it being too long to deal with, and why a short ester is preferred?

Much appreciated if you can :slight_smile: