Take Note, Men: New Male Contraceptives Are on the Way
Research is well underway for multiple male contraceptive methods, including a topical gel, a pill, and an injection.
A transdermal gel could be developed for market in as little as ten years.
Other products will take longer, but birth control methods like a non-hormonal pill for men show promise in animal models.
Men usually rely on just two options to take control of their reproductive ability. The only male-specific contraceptive options available for generations have been condoms or the more invasive option—vasectomies.
But those limits may expand in as little as 10 years, as male contraceptive research over the past few decades has been building toward multiple lines of contraceptive methods, including pills, injections, and perhaps most promising of all, a simple gel that men can apply to their shoulders once a day. And over the past two years, human trials for a hormone contraceptive gel have proven so far to be an easy and effective solution for men, with few and minor side effects, according to new research in the journal Andrology.
In the recent trial, nearly 100 monogamous heterosexual couples recruited from all over the world tried out the gel in question: Combined Nestorone/Testosterone gel.
Each man who started the gel therapy—a metered pump dispensed exactly the right amount, a little more than 2 milliliters, to be rubbed on their upper arm or shoulder daily—registered lowering sperm counts within weeks. Once the count was less than 1 million sperm per milliliter, as opposed to the normal level of millions of sperm, the woman in the couple stopped her own contraceptive method. For a year, the couples relied only on the male side of contraception to avoid pregnancy. At the end of one year, the man stopped using the gel, and his sperm count bounced back to normal levels in about 16 weeks.
Most men in the study experienced little to no side effects when they used the gel properly, and those effects were minor and similar to side effects some women taking hormonal pills may experience, such as weight gain, acne, lowered libido and slight mood changes.
Researchers say the therapy worked because none of the couples became pregnant, and sperm counts stayed low while the men continued using the gel for the trial year. Men were monitored frequently for sperm count and overall health. Some of these couples chose to start families after they finished using the gel, and they have gotten pregnant. Researchers are now close to recruiting 350 couples out of the 420-couple goal, in order to expand their data set.
Christina Wang of the Lundquist Institute at Harbor-UCLA Medical Center is involved in the gel development and trials and said she has seen men’s interest in family planning rise over the decades. “We feel that the man is more open in sharing an interest in family planning,” she tells Popular Mechanics. “I think the time has come, but we have to deliver the product, right?” It takes time to ensure a new drug is safe, so contraceptive development can’t be rushed, she says.
Male contraception research is sponsored by National Institute of Child Health and Human Development in collaboration with the Population Council, which developed the Nestorone. NIH provides the overall funding.
How does the gel work?
Nestorone/Testosterone gel is a combination of two hormones, a progestin and testosterone. The latter is known as the male hormone, because it is responsible not only for male reproductive function, including sperm production, but also for general good health in males. It affects bone mass, fat distribution, muscle mass and strength, and the production of red blood cells, according to the NIH.
When a person takes a dose of progestins, the resulting rise in the body’s progestin level shuts down the reproductive cycle before it begins. Adding back some testosterone maintains healthy levels in the body, as well as sex drive. For similar reasons, female hormonal contraceptives contain a progestin hormone and some estrogen, the “female” hormone that impacts health in myriad ways.
An oral version of testosterone has been tested, but because it adversely affects the liver, it’s not an attractive option. Plus, ingested testosterone breaks down too quickly and has to be taken multiple times a day, so it’s not very practical, Diana Blithe, program chief of the NIH Contraceptive Development Program (CDP) tells Popular Mechanics. A transdermal application, in which the body absorbs the hormones slowly through the skin, is easier to use and has shown to have fewer, if any, side effects.
A non-hormonal male contraceptive in the works
Debra Wolgemuth, a professor of genetics and development at the Columbia University Medical Center and associate director for research at the Institute of Human Nutrition, has been interested in gaining genetic control over sperm development for decades. That’s because from her view, it’s easier to work on sperm cells than eggs, she tells Popular Mechanics, because millions of new sperm are made each day. Females are born with about a million egg cells, but only about 300 to 400 eggs in a human female potentially can lead to pregnancy.
A second way researchers in Wolgemuth’s lab found to stop sperm production is through a pharmacological antagonist—a drug compound that inhibits a necessary chemical process in the body. In this case, the process the research team wants to prevent is spermatogensis, or the creation of new sperm cells.
Researchers like Wolgemuth and Sanny Chung, an associate research scientist in the Wolgemuth Lab, are looking for a drug that would prevent the body from using retinoic acid, a critical compound from vitamin A that’s necessary for sperm production.
Chung is testing possible drug compounds in mice. In a 2011 study published in Endocrinology, a drug compound successfully interfered with the signaling pathway of mouse cell receptors that are designed to pick up and use retinoic acid, making the mice sterile. At the same time, they experienced no bad side effects, Chung says.
Even though it was shown to work well in mice, future drug development steps will take time, Wolgemuth says. Since their mouse model studies began, the team has been able to lower the drug dose and still find it effective.
Hormonal treatments for women, like the pill, are blamed for side effects like weight gain, acne, and mood changes, to name a few. The same occurs to some extent in male hormone trials like the gel.
Blithe warns against thinking that a non-hormonal solution equals no side-effects. “I don't think anything that one takes systemically can be guaranteed to not have side effects. So we don't know… till we get into humans, but it's an exciting pathway. And I really think it’s going to work,” Blithe adds.
A Short History of Contraceptives
Condoms may date from the Bronze Age, with the first written mention of animal bladders and later, animal skins being used for protection against disease (but not necessarily pregnancy) during intercourse, according to an article in the Indian Journal of Urology. The modern condom was introduced in the mid-1800s, when inventor Charles Goodyear, of the Goodyear tire, introduced rubber vulcanization, whereby natural rubber and sulfur are combined under heat to create a durable, elastic material. By 1860, condoms were produced on a large scale, and were the earliest form of the latex condom we know today.
For women, a scientific and reliable method for prevention of pregnancy came much later. It wasn’t until around 1960 that “the pill” became the first well-known oral contraceptive method. It developed further, with several varieties of hormone combinations produced by different drug companies. Today, the pill is still exclusively a female method to prevent pregnancy, but women can also choose from several different methods, including the pill, the patch, the vaginal ring, the sponge, the injection, the intrauterine implant (IUD) and the diaphragm.
You Might Also Like
