The WHO/CONRAD Injectable Trials
1990s-2016 Hormonal Efficacy Studies and the Behre 2016 Halted Trial
Evidence grade 3 of 5, Mixed. Read how the Atlas grades evidence.
The written rationale for this grade is still being prepared.
- FDA
- Investigational; trials demonstrated efficacy but none led to an approved product
Reference only. Not medical advice.
What can go wrong
Reported adverse events in the 2016 study included acne, injection-site pain, increased libido, mood changes, and a small number of depression cases; there was also at least one reported event the committees weighed heavily. As with all hormonal regimens, the risk profile (mood, acne, lipids) is the central barrier, not lack of efficacy.
This is something to take to a clinician. The Atlas can tell you what is known about the who/conrad injectable trials in general. It cannot tell you what is happening in your body, and the difference matters most for exactly the symptoms that bring people to this page.
WHO-coordinated trials in 1990 and 1996 first proved that suppressing sperm to azoospermia or severe oligozoospermia gives effective contraception. The most cited modern trial - Behre et al., published in the Journal of Clinical Endocrinology & Metabolism (JCEM) in 2016 - tested injectable testosterone undecanoate plus norethisterone enanthate every 8 weeks. It achieved strong suppression and a low pregnancy rate, but the study's recruitment was stopped early by the funders' safety review committee over side effects including mood changes, depression, and acne, igniting a public debate about a contraceptive double standard.
The studies that proved it works - and the one that proved how easily it gets shelved.
What people take it for
These are the reasons people give for taking it. They are not effects it has been shown to have.
How it is supposed to work
Both the WHO androgen-only studies and the Behre androgen-progestin study work through the same axis: injected testosterone (plus, in later trials, a progestin) suppresses LH/FSH, collapses intratesticular testosterone, and halts spermatogenesis. The 8-weekly injection schedule of testosterone undecanoate aimed to reduce dosing frequency versus the weekly testosterone-enanthate regimens of the 1990s studies.
What the 2016 halt actually showed
Independent safety committees, not the investigators, stopped recruitment. Among the reported adverse events, most were rated mild-to-moderate, and many participants said they would use the method if available - yet the trial was paused. Commentators noted that depression, mood change, and acne are listed side effects of widely approved female hormonal contraceptives, and argued the asymmetric reaction reflected lower societal tolerance for risk in men who do not bear pregnancy. Others maintained the discontinuation was appropriate given the specific severity and frequency signals seen.
What people get wrong
Often saidThe 2016 trial failed because the drug didn't work
ActuallyIt worked - suppression and contraceptive efficacy were strong. Enrollment was halted over side effects, not lack of efficacy.
Often saidThe men in the trial wanted out
ActuallySurveys within the study found many participants would still use the method despite the side effects, fueling the double-standard argument.
Who profits, and who pushes back
Critics of the early halt
The side effects that stopped this trial - mood changes, acne - are accepted on female methods used by millions; the reaction reveals a double standard.
Defenders of the safety decision
Discontinuation followed predefined safety governance; specific severity signals, not squeamishness, drove the decision.
At a glance
- Behre 2016 regimen
- Testosterone undecanoate + norethisterone enanthate IM, every 8 weeks
- Behre 2016 journal
- J Clin Endocrinol Metab (JCEM), 2016
- Efficacy signal
- High suppression; low pregnancy rate among continuing couples
- Why halted early
- Funder safety committees stopped enrollment over mood/depression, acne, and other side effects
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about The WHO/CONRAD Injectable Trials. A short entry is not a safe entry.
- Cost and market. We have not documented what it sells for or who sells it.
- Supply chain. We have not mapped where it is made.
- Who uses it. We have not documented the user groups.
- What could change. No forward-looking summary yet.
- How it compares. We have not set it against the alternatives.
- Children and teenagers. We have not checked what is known about younger people.
- Where we land. We have not taken a position on this yet.
Sources
The studies below are named and described, but not linked. You cannot open them from here and check our reading against them, which means this page is our summary of the literature rather than a document you can verify. Weigh it accordingly until the links exist.
The studies that matter
WHO Task Force, Lancet1990
Testosterone enanthate-induced azoospermia provided effective, reversible contraception in most men
WHO Task Force, Fertil Steril1996
Severe oligozoospermia also gives high contraceptive efficacy, broadening the usable threshold
Behre, Zitzmann, Anderson et al., JCEM2016
TU + NET-EN every 8 weeks suppressed sperm effectively with low pregnancy rate, but enrollment was halted early by safety committees over side effects