New forms of birth control are always an exciting thought for anyone who can become pregnant—especially if it means letting men take on some of the responsibility of contraception. So we understand why the Internet totally freaked out this week about the possibility of a new male birth control pill. But, sadly, the study everyone’s excited about is just barely the beginning. And a new pill isn’t even close to being available.

The study, presented this week at Endo 2018, this year's annual meeting of the Endocrine Society, looked at whether or not two different formulations of dimethandrolone undecanoate (DMAU) could suppress male hormones (including testosterone) to the level that they would prevent sperm production. However, this was a Phase 1 trial, meaning it was only looking at a small number of people for a short amount of time, and it focused mostly on whether or not DMAU, a compound that binds to both androgen and progesterone receptors, is safe—not its effectiveness at preventing pregnancy.

The study found that taking DMAU could lower men's testosterone levels. But it didn’t actually look at how this affected their sperm production.

For the study, 100 men between the ages of 18 and 50 were randomly assigned to receive either DMAU or a placebo for 28 days. The men getting DMAU got one of three doses (100, 200, or 400 mg) and one of two formulations (castor oil and benzyl benzoate, or powder in a capsule), all taken with food.

At the end of the 28 days, 83 of the 100 participants finished the study. All of the men taking DMAU had lower levels of testosterone after 28 days, with the most significant changes seen in men taking the 400 mg dose. Taking 400 mg of DMAU also significantly suppressed two other important hormones: follicle stimulating hormone (FSH) and luteinizing hormone (LH).

Here’s the thing: The researchers didn’t look at how all this affected the participants’ sperm. Even though previous research found that testosterone, FSH, and LH levels this low suppressed sperm production, this study didn't test for that, Stephanie Page, M.D., Ph.D., lead study author and a professor in the department of medicine at the University of Washington, tells SELF. So we can’t make any claims about how this would actually work as a birth control pill for dudes.

There’s a reason it’s so damn hard to create a birth control pill for men: Lowering testosterone to a point that would inhibit sperm production comes with some pretty horrible side effects.

Let’s back up a bit to explain how testosterone and sperm are related. Sperm production is the result of a complicated process involving multiple hormones, Peter J. Stahl, M.D., an assistant professor of urology at Columbia University Medical Center, tells SELF. “The testicles do two things: They make sperm and they make testosterone,” he says. In fact, testosterone is necessary for the production of sperm.

But testicular function and sperm production are regulated by the hypothalamic-pituitary-gonadal (HPG) axis. Essentially, the brain’s hypothalamus produces gonadotropin-releasing hormone, which causes the pituitary gland to produce FSH and LH. Those then signal the testicles to produce testosterone. But if the receptors in the pituitary sense that there’s too much testosterone in the bloodstream, that forms a negative feedback loop. As a result, the body will slow down and eventually halt the production of testosterone, causing sperm production to drop as well.

Theoretically, then, giving someone extra testosterone would cause the body to produce less of its own testosterone and, therefore, less sperm. So why don’t we just use testosterone as a male contraceptive?

Well, shutting off the testosterone valve has, historically, been pretty disastrous. Testosterone does a ton of different things, and not all of them are related to sex, Dr. Stahl explains. Low testosterone is associated with symptoms such as decreased libido, erectile dysfunction, and depression, he says. And in the long-term it can also cause low bone density, changes in body composition, and changes in red blood cell production.

So, a male birth control pill that lowers testosterone (and sperm production) would need to do so without all the side effects of low testosterone.

“We really want for these medications to suppress [the production of sperm], but we know other parts of our body are sensitive to these hormones,” Paul Gittens, M.D., urologist and sexual medicine expert at the Centers for Sexual Medicine, tells SELF. So, the ideal situation would be to find a drug that could affect testosterone’s role in sperm production without setting off those other side effects—and that’s what researchers are hoping DMAU can do.

Because DMAU is a synthetic hormone that mimics the effects of testosterone, it can fool the pituitary into suppressing the body’s natural testosterone production, Peter Schlegel, M.D., urologist in chief at NewYork-Presbyterian and a professor of reproductive medicine at Weill Cornell Medicine, tells SELF. If testosterone is suppressed enough, it won’t be signaling the testicles to produce sperm. Eventually, the idea is that sperm production will be suppressed to the point that a patient wouldn’t be able to get someone pregnant. At the same time, it would ideally provide the effects of an androgen (a male sex hormone) in the rest of the body, to mitigate the side effects of low testosterone.

Another unexpected challenge: making this a daily pill. “The challenge with giving testosterone by mouth is that it goes straight to the liver and causes all kinds of liver complications and side effects,” Dr. Schlegel says. So the preferred method of giving people testosterone has become injections or topical gels. But because DMAU isn’t an active form of testosterone (it’s a prodrug, meaning it needs to be metabolized by the body to turn into its active form), the liver doesn’t have to deal with breaking down actual testosterone.

Some of the men in this study did report side effects associated with low testosterone, but we’ll need longer and larger studies to really know how serious they are.

Several of the participants reported weight gain, acne, and a decreased sex drive. And most of those effects were significantly more common among those taking DMAU than those getting the placebo. However, there wasn’t a specific dose at which the side effects started showing up, Dr. Page says.

The libido effects will likely be the most important—and the trickiest—ones to figure out, says Dr. Page. The sexual diaries and questionnaires the researchers gave participants to fill out during the study didn’t show any reduction in sex drive, she says, but eight participants in the DMAU groups and one in the placebo group did report a decrease in libido when asked in person. “We aren’t sure what to make of the discrepancy, but we are going to be examining this more in the next study,” Dr. Page says.

The decreased libido is especially concerning, Dr. Gittens says. “It’s something you really have to pay attention to” in future studies, he notes. Dr. Stahl agrees, pointing out that a drug you’re taking so that you can relax and enjoy your sex life probably isn’t going to be super helpful if it also causes a decrease in sex drive. (Pretty sure every woman who experiences low libido as a result of their birth control method can attest to that.)

Experts all agreed that it would take longer studies with more participants to really see the full potential for side effects, particularly because other side effects of testosterone suppression could take years to appear. “For some of the effects on bone marrow density, you might not see anything for two or three years,” Dr. Stahl says. And changes in body composition might take between six and 12 months. So, ideally, he’d like to see studies showing effects of the drug after three, six, and 12 months. And, because it takes between two and three months to produce sperm, it could take up to three months to assess whether or not sperm production really stops, Dr. Schlegel says.

The next step for Dr. Page’s team is to do a longer study anyway, which would also help them find the right dose with the fewest side effects. "The fine tuning will hopefully help mitigate some of [the side effects]," she says, meaning that researchers could find a lower dose that's still effective at suppressing sperm but doesn't produce as many other issues. But the potential longer-term side effects of taking DMAU (and whether or not sperm production would return after stopping the drug) aren't clear yet.

“This is an early study, but it’s an encouraging, different approach because it’s a pill you can take on a daily basis,” Dr. Schlegel says. There isn’t anything like that available for men right now.

This is one of many male birth control options currently being studied, but all of them are a long way away from being available.

Other forms of male birth control in the works include a topical gel, a gel injected into the vas deferens that mimics the effects of a vasectomy, and an injectable hormone combination. Unfortunately, all of these are years away from being available. Dr. Page says she's "hopeful" that with adequate funding her team could accelerate the production of the drug to have it available within 10 years.

Until then, we have plenty of other effective contraceptive options, including combined oral contraceptives, long-acting reversible forms (such as the IUD), and good ol' condoms, which have the added benefit of protecting against STIs. Men also have the option of a vasectomy, which involves cutting the vas deferens to prevent semen from making it from the testicles to the prostate.

So, yes, the burden of birth control continues to fall mainly on women. But that doesn't mean men are trying to stay out of it. In fact, according to results from several international surveys, the majority of men would definitely be ready to get on board if they had more options.

"Men are interested in taking a role in contraception, but they don’t have a lot of choices now," Dr. Page says. "We’re excited about trying to provide men those choices."