SACRAMENTO, Calif. — Every evening before he goes to bed, graduate student Daniel Castaneda does something that only a handful of men in the world can do right now: he applies his birth control.
“You just put it on your shoulders, both sides, and it’s usually pretty quick,” Castaneda said.
The birth control takes the form of a gel, dispensed from a pump canister similar to some hand sanitizers or liquid soaps. Once a day, Castaneda pumps a dose about the size of a tablespoon for each shoulder, rubbing it in completely so that it’s absorbed by his skin.
But this gel is not available to everyone yet. It’s still under study.
Daniel Castaneda and his partner Nina Gonzalez are one of several couples currently participating in trials for the male contraceptive gel at UC Davis. This writer is also a current participant.
If trials are successful, the drug would be the first of its kind on the market.
“It’s been nice for me not to have to worry about it,” Gonzalez said. “And it’s also fun just to tell my friends like, 'Oh, I’m actually not on birth control, my partner is.'”
The gel was developed by the Population Council and Eunice Kennedy Shriver of the National Institute of Child Health and Human Development (NICHD). UC Davis Health joined several other institutions around the world as a trial site in Phase 2 of testing.
“Male contraception has always been that enigma,” said Dr. Mitchell Creinin, the Director of Family Planning and the lead study investigator at UC Davis Health. “And people have been asking for years: why isn’t there the male pill?”
For men, options for birth control are limited to condoms and vasectomies. There are no hormonal contraceptive drugs available to men, as there are to women. This gel could change that. It’s currently known by the names of the two hormones that make up its formula: nesterone and testosterone.
“The nesterone part just tells the body to stop stimulating the testes from doing what it does, which is making hormones and making sperm. And that’s great! If it doesn’t make sperm, then you can’t cause a pregnancy,” explains Dr. Creinin.
Nesterone is also used in some women’s birth control. In men, one of the hormones it tells the body to stop producing is testosterone. Without testosterone, men tend to lose energy, focus, and their sex drive, among other things. The gel includes testosterone to try to keep men’s testosterone levels normal while using the gel.
“We already have gels that are available on the market to help men who have naturally low testosterone,” Dr. Creinin said. “So that part in the gel isn’t hard. It’s getting the other part correct, and that’s what’s been the special part of this product.”
Couples considering participating in the trial may have some of the same questions that Castaneda and Gonzalez did.
“Well, just whether it’s going to work, right?” Castaneda said of his concerns. “Am I going to be able to have children if I want to have children down the line?”
Nesterone does not suppress a man’s sperm count immediately. While it tells the male body to stop producing new sperm, millions of sperm stored in the body must first be emptied before levels are low enough to not cause a pregnancy. For that reason, couples in the study are expected to use other forms of contraception in addition to the gel until the man’s sperm count has reached a low enough level.
Dr. Creinin says that a very small percentage of men across all study sites did not suppress their sperm count to sufficiently low levels on the gel, but those couples do not continue with the study.
“We don’t let anybody use this as a contraceptive in their relationship until we’re certain that their counts are suppressed incredibly low,” he said.
Men’s sperm counts are continuously monitored throughout the study, including after they’ve stopped using the gel to make sure their sperm counts return to normal. Dr. Creinin says all male participants in the trial thus far have returned to normal levels after discontinuing use of the gel.
As for how well the gel seems to be working, Dr. Creinin says results to this point have been very good.
“In men who use the gel and their sperm counts go down to very low levels–in fact, they go down pretty much to zero–we find that with continued use of the gel, we're not seeing anything that shows any signs of pregnancy. We’re not finding any pregnancies thus far,” he said.
Like with most drugs, there can be side effects.
“For me, I mean I haven’t really noticed any significant side effects. The only thing possibly is gaining some weight, but not anything significant or cause for concern,” Castaneda said.
Dr. Creinin adds that some men can “feel a little bit moody” or have skin irritation from the alcohol-based gel, and for some these side effects go away over time, while some experience them for longer.
Couples are allowed to leave the study at any time, for any reason. Dr. Creinin says that the study’s discontinuation for side effects are low, and reports of side effects from participants in general also remain low for the time being.
“As far as we can tell, everything looks really promising,” he said.
Despite the promising outlook of trials, it could be a long time before the contraceptive gel is available. Dr. Creinin estimates at least ten years before it might be available on the market.
If that day comes, Dr. Creinin says it would be a “huge victory for couples.”
“I think there’s a lot of men who want to step up and be a very active part of highly effective contraception,” he added.
Castaneda and Gonzalez said they would strongly consider getting back on the gel if it were to be approved. For Gonzalez, she says it’s been a good experience for her not to have to experiment with different contraceptives and their various side effects for herself.
“I just had kind of not good experiences being on contraception,” she said. “As I’m sure is the tale for most women.”
And they both agree that it would be a step in the right direction to give men a new opportunity to shoulder the responsibility of birth control.
“I think that’s pretty exciting, right? Something that hasn’t really been a possibility,” Castaneda said.
“In an ideal world, it would sort of flip the script that we currently have where we sort of villainize young women who get pregnant as though it’s their own fault,” Gonzalez said. “And it might put more of the responsibility on young men as well.”
UC Davis Health is currently recruiting more couples for continued study of the contraceptive gel. More information is available here.