An attempt to develop a safe and effective "male pill" is progressing, according to the preliminary results of a small study.
In a four-week trial of men under the age of 50, a hormone-based experimental contraceptive pill was found to be "well tolerated".
And the participants' testosterone levels significantly decreased along with two hormones essential for sperm production, the study team observed.
Study author Dr. Stephanie Page described the results as "a promising step forward" in the development of a male version of the female contraceptive pill.
But do not get rid of your condoms at the moment. Page added that "clearly larger and longer-term studies are needed to address possible side effects."
The interest in a male contraceptive pill is strong, he said.
"Women have many options, but many women can not hormonal and other methods available to them," said Page, who heads the division of metabolism and endocrinology at the University of Washington in Seattle.
"Men are increasingly interested in sharing the burden of contraception, as well as controlling their own fertility," he noted.
For the study, the researchers evaluated three doses (100, 200 and 400 milligrams) of a once-a-day birth control prototype called dimendrolone dimetanolate (DMAU). Two formulations were tested inside the capsules, either powder or castor oil.
DMAU combines the activity of a hormone such as testosterone and a progestogen. It was developed by the US National Institutes of Health. UU., That funded the study.
Differ from previous attempts to create a male contraceptive pill in several ways. It contains only one steroid, instead of two, and was not associated with any liver toxicity, something that has plagued the previous efforts of the male pill, Page said. And "unlike other oral testosterone derivatives, DMAU only needs to be dosed once a day," he added.
For the study, the researchers randomly divided 100 men into groups of 20 or less. Some men received a sugar pill (placebo), while others were given a daily oral dose of DMAU in one of the three doses chosen. DMAU was always consumed with food.
Blood tests revealed that with the highest dose, DMAU suppressed the production of testosterone and two other hormones, LH and FSH, that are key to sperm production.
But none of the study participants shows complications that may arise from testosterone deficiency, such as mood swings or alterations in terms of sexual function.
However, all those who took DMAU experienced a slight weight gain (approximately 3 to 9 pounds) and a slight decrease in the so-called "good" cholesterol (HDL). No serious side effects were reported.
Page added, however, that a fall in sperm-producing hormones "is not the same" as the demonstration of an actual fall in sperm count.
"We have to do a longer test – three to six months – to show that sperm production is reduced with prolonged use of DMAU," he said. Twenty-eight days "is not long enough" to fully answer that question, he explained.
"However, we know from our work, and from many others in the field, that the degree of 'sperm support' of the hormonal suppression we have observed in this study should be adequate to prevent the sperm maturation, "said Page
He reiterated that" this was a very small study and there is still a lot of work to be done ". That follow-up effort is underway at the University of Washington and LA Biomed Harbor-UCLA.
According to Page, multinational surveys indicate that most men are interested in more options for reversible contraception.
Currently, the reversible male condom is the condom, which is not the most reliable method of contraception, he said.
The results of the study were presented in Chicago at a meeting of the Endocrine Society. Research published at meetings is generally considered preliminary until it is reviewed for publication in a medical journal.
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