White Coat, Black Art

A male contraceptive that works!

A male contraceptive needle is almost as effective as the female birth control pill - but side effects could be a deal breaker.
The male contraceptive is an injectable mixture of two medications. ((iStock))

Step up gents, there's a new contraceptive in town.

In 1960, the U.S. became the first country in the world to approve the pill as an oral contraceptive, ushering in the sexual revolution, and giving women control over unwanted pregnancy. But for more than a half century, birth control medication for men has remained unavailable. That may be about to change, thanks to developments around a new male contraceptive.

The male contraceptive is a needle that is a mixture of two medications. One is a long-acting progesterone called norethisterone enanthate. The other is a long acting drug called testosterone undecanoate.

The progesterone gets the pituitary - the so-called master gland - to switch off sperm production. But shutting down the pituitary also reduces levels of the male hormone testosterone, which is necessary for well being. The testosterone injection is supposed to counteract that effect.

The injections turned out to be extremely effective. Researchers from five countries and the World Health Organization recruited more than 300 men in long-term monogamous relationships. In the first phase of the trial, the men received injections of each of the drugs every eight weeks for up to 26 weeks. Doctors monitored their sperm counts. Once the count was reduced to less than 1 million sperm per ml of semen, couples were instructed to rely on the male contraceptive as their primary method of birth control and not to use any other method during the study.

They were followed for just over a year - with the men continued receiving periodic injections. The male contraceptive was 96 per cent effective in preventing pregnancy. Among the 274 men who achieved a low sperm count, there were four pregnancies. That made it more effective  than condoms - which have eighty-two percent success - and approaching similar effectiveness as the pill.

As with the pill, there are side effects. They included pain at the injection site, muscle pain, and acne.  Some men had increased libido. Side effects probably caused by the medications (according to the researchers)  included one case of depression, one intentional overdose of acetaminophen, and an irregular heart beat that returned normal after stopping the injections. Twenty men quit the study because of adverse effects. In particular, the risk of depression convinced researchers to stop enrolling new participants. They're trying to figure out how to tweak the dose of hormones to get birth control with fewer side effects.

There are other male contraceptives in the pipeline. Researchers from the United Kingdom and Portugal have discovered a peptide chemical that penetrates the sperm cell and switches off its ability to swim, thereby causing temporary infertility. This kind of male contraceptive could work almost instantly. The researchers say it could be packaged into a skin patch, pill or a nasal spray that could be taken hours of possibly even minutes prior to having sex. The effects would wear off within hours or days. The peptide has been tested on animal and human sperm in the lab.  Animal testing is expected to begin in the next two to three years.

There's no doubt that a male contraceptive would change things between men and women. It might turn birth control into a shared responsibility. If women have their doubts, consider this: despite side effects like depression, three quarters of the men who got the male contraceptive needle said they were willing to continue receiving it.

I wonder just how likely it is that women will trust their male partners to go to their appointments and get their birth control shots.


To encourage thoughtful and respectful conversations, first and last names will appear with each submission to CBC/Radio-Canada's online communities (except in children and youth-oriented communities). Pseudonyms will no longer be permitted.

By submitting a comment, you accept that CBC has the right to reproduce and publish that comment in whole or in part, in any manner CBC chooses. Please note that CBC does not endorse the opinions expressed in comments. Comments on this story are moderated according to our Submission Guidelines. Comments are welcome while open. We reserve the right to close comments at any time.

Become a CBC Member

Join the conversation  Create account

Already have an account?