"And 60 to 80 percent of men surveyed in such studies say if there was a reversible contraceptive available, they would be very interested in using it".
The researchers found that the proposed hormone pill, called dimethandrolone undecanoate or DMAU, effectively reduced testosterone and other hormone levels responsible for sperm production without any serious side effects, according to Dr. Stephanie Page, an endocrinologist at the University of Washington School of Medicine and a lead author of the study.
The new pill is known as DMAU and works similarly to the female birth control pill, using a combination of hormones to lower sperm count below the amount needed for a female to become pregnant, according to US News & World Report.
Long-term studies are the next step towards a male contraceptive pill a day.
However, DMAU contains undecanoate, a long-chain fatty acid, which Page said slows this clearance.
The investigators tested three different doses of DMAU - 100, 200, and 400 milligrams, or mg.
At the end of the study the 83 men gave their blood samples for testing hormone levels as well as cholesterol levels.
"Despite having low levels of circulating testosterone, very few subjects reported symptoms consistent with testosterone deficiency or excess", Page added. The men gained between 3 and 9 pounds, and their HDL or "good" cholesterol levels fell slightly - something that might, over time, raise heart disease risk.
Talks about developing a male contraceptive pill have been discussed for years.
Dr Page said longer term studies are now underway to confirm that when taken every day, DMAU blocks sperm production.
The researchers administered the pill to a man for one month saying that it did not damage the liver - a side effect shown in previous trials of oral hormonal contraceptives. It's 99 per cent effective when taken perfectly, Planned Parenthood wrote, but added that it's hard to do this.
Volunteers took the drug for 28 days once daily with food.
Researchers, however, said that further studies are still needed to verify that the pill can indeed block sperm production. "They would have hot flashes just like women do when they go through menopause, and they would have marked changes in sexual desire and function", she said.
The study did not also show if the pill could stop couples from conceiving, and it only involved a small number of participants.