The first injectable male contraceptive could be on the way after a trial in Australia proved 100 per cent effective, scientists said today.
In the study, 55 men received hormone treatment over a year containing a combination of the male hormone testosterone and progestin, which is used in female contraceptive pills, in an attempt to "switch off" sperm production.
None of the men showed any side effects and none of their partners became pregnant, scientists from the Anzac Research Institute in Sydney said.
Prof David Handelsman said in a statement on the institute's website: "This is the first time a reversible male contraceptive that will suppress sperm production reliably and reversibly has been fully tested by couples.
"We used a hormonal implant to replace testosterone given every four months and the progestin DMPA was injected every three months.
"This shows the way for a final product to be a single injection containing testosterone and a progestin which will easily be given by local doctors on a three-four monthly basis and still maintain male sexual health," Prof Handelsman said.
Previous attempts to develop an effective and convenient male contraceptive have encountered problems over reliability and side effects, such as mood swings and a lowered sex drive.
Prof Handelsman added: "As researchers we have done as much as is possible. It is now over to the companies to develop a convenient and acceptable product. We have proved that it is possible for them to do it."
PA