There’s a reason pills aren’t included on this list. Vaccines, along with DNA, RNA, and antibodies, belong to a class of drugs called biologics, which are made of molecules too large to be administered orally—their size means that they’d be broken down by the enzymes in the digestive system before they could be absorbed into the blood. But researchers at the Massachusetts Institute of Technology think they’ve found a workaround, albeit one that seems a little bit counterintuitive at first: To avoid the sting of an injection, swallow a pill that’s covered in needles.

In a study recently published in the Journal of Pharmaceutical Sciences, the researchers found that such a pill safely delivered insulin to pigs by injecting it into the lining of their stomachs without causing any harm. The reservoir for the insulin was hidden by the pill’s dissolvable coating; as it made its way through the gastrointestinal tract, the coating melted away, revealing five-millimeter needles that successfully injected the drug—a discovery that could have implications for a wide range of (human) treatments currently administered with a needle and syringe.

“If you look at medication noncompliance, a significant portion can be attributed to some of the difficulties that are associated with injectables,” says study co-author Giovanni Traverso, a gastroenterologist at Massachusetts General Hospital. An injection “means training a patient or having a nurse or a physician administer it, and it can be uncomfortable.”

With the ease of an oral alternative, he says, “Our sense is that there would be more patients who would be more adherent with their treatments, and therefore be treated appropriately for their conditions.”

Well, sure, if you can convince them to swallow a needle pill.

But “these are very small needles,” Traverso says. “Things like bones would be bigger, people who accidentally ingest fish bones.” (For additional reference, he also compared them to “the hair on a kiwi,” and a hangnail.) Because there are no pain receptors in the gastrointestinal tract, he says, patients wouldn’t be able to feel the needle stick.

And because of the pliable nature of the GI tract, he added, it wouldn’t shred, tear or otherwise damage a patients’ insides. “There’s a great deal of compliance at the level of the tissue,” Traverso explains. “It’s not a hard surface that you can push against. It’s very soft. In order to cut something, you need something else pushing in order for that sharp edge to pierce.”

So, okay, it’s safe to swallow, and it’s safe as it winds its way through the body. But what about, um, the other end?

They’re working on it, he tells me. For now, “you would pass it just as you would with any waste product.” But for next steps, Traverso and study co-author Carl Schoelhammer, a graduate student at MIT, are working on a fully biodegradable version of the pill, as well as one with needles made of sugar that dissolve after doing their job.