Related Experiment Video
Updated: Jul 5, 2026
06:24
Establishment of Rat Models Mimicking Gender-affirming Hormone Therapies
Published on: January 10, 2025
Male hormonal contraception: a double-blind, placebo-controlled study
Ellen Mommers1, Wendy M Kersemaekers, Jörg Elliesen
1Global Clinical Development Department, Organon, part of Schering-Plough, Oss, The Netherlands. ellen.mommers@organon.com
The Journal of Clinical Endocrinology and Metabolism
|April 17, 2008
Summary
This study shows a new etonogestrel implant and testosterone undecanoate injection combination effectively suppresses sperm production in men for contraception. The method is well-tolerated and reversible, with good recovery rates after treatment cessation.
Area of Science:
- Reproductive Endocrinology
- Contraceptive Development
- Male Reproductive Health
Background:
- Assessing novel hormonal male contraception methods.
- Evaluating etonogestrel (ENG) implant and testosterone undecanoate (TU) injections.
- First large-scale placebo-controlled trial for male hormonal contraception.
Purpose of the Study:
- To evaluate the efficacy and safety of a combined etonogestrel implant and testosterone undecanoate injection regimen for male contraception.
- To assess the degree and duration of spermatogenesis suppression.
- To determine the reversibility and recovery of sperm production post-treatment.
Main Methods:
- Double-blind, multicenter randomized controlled trial.
- 354 healthy men received either low- or high-release ENG implants with TU injections or placebo.
- Treatment duration of 42-44 weeks with at least 24 weeks of follow-up.
Main Results:
- Spermatogenesis suppression to ≤1 million/ml achieved in 89% of men by week 16, maintained in 91% through treatment.
- Median sperm concentration recovery to >20 million/ml was 15 weeks (mean 17 weeks).
- Treatment was generally well-tolerated, with minor increases in adverse events like weight gain and mood changes compared to placebo.
Conclusions:
- The ENG implant and TU injection combination is an effective and reversible male hormonal contraceptive.
- The method demonstrates good tolerability and spermatogenesis suppression.
- Potential for improvement exists through dose regimen or application mode adjustments.
Related Concept Videos
01:22Birth Control Methods
Vasectomy is a surgical form of male sterilization that involves severing and sealing the vasa deferentia, preventing sperm from mixing with semen during ejaculation. Because a vasectomy does not impact the testes' ability to produce testosterone, hormone levels, libido, and sexual function generally remain unchanged. While vasectomy is highly effective in preventing pregnancy, with a success rate near 99.85%, rare cases of recanalization (spontaneous reconnection) can occur. Although vasectomy...
01:11Blinding
Blinding is a commonly used method of not telling participants which treatment a subject is receiving. Blinding is a critical part of a randomized control trial or RCT. It reduces the bias that affects the results. In an RCT, blinding is used in the form of a placebo. A placebo effect occurs when untreated subjects falsely believe they have received the treatment and report improved symptoms. A placebo or a dummy treatment is administered to subjects to negate the bias caused by such an effect.
02:07Blind Procedures
Ideally, the people who observe and record the children’s behavior are unaware of who was assigned to the experimental or control group, in order to control for experimenter bias. Experimenter bias refers to the possibility that a researcher’s expectations might skew the results of the study. Remember, conducting an experiment requires a lot of planning, and the people involved in the research project have a vested interest in supporting their hypotheses. If the observers knew which child was...
01:22Hormonal Regulation of the Menstrual Cycle
The ovarian cycle regulates endometrial changes throughout a single menstrual cycle via the coordinated action of gonadotrophin-releasing hormone (GnRH) and gonadotrophins.
At puberty, GnRH begins a pulsatile release pattern, which triggers the anterior pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The frequency and amplitude of GnRH pulses vary across the menstrual cycle, with faster pulses favoring LH release and slower pulses favoring FSH release.
At puberty, GnRH begins a pulsatile release pattern, which triggers the anterior pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The frequency and amplitude of GnRH pulses vary across the menstrual cycle, with faster pulses favoring LH release and slower pulses favoring FSH release.
01:33Hormonal Regulation
The renin-aldosterone system is an endocrine system which guides the renal absorption of water and electrolytes, thus managing blood pressure and osmoregulation. Activation of the system begins in the kidneys with a small cluster of cells adjacent to the afferent and efferent blood vessels of the renal corpuscle. As the nephrons are filtering blood, juxtaglomerular cells monitor blood pressure. If they detect a decrease in pressure, they release the hormone renin into the bloodstream.
01:40Hormonal Regulation
Hormones regulate a significant portion of digestion through activation of the neuroendocrine system. The neuroendocrine system of digestion contains many different hormones all with multiple functions that are both, directly and indirectly, involved in digestion.