With the summer festival circuit in full swing, party drugs are more ubiquitous than ever. But are those little pills really what they promise to be? And do users actually care? No, and yes, according to a new research paper in the Journal of Psychopharmacology.

The street drug Methylenedioxymethamphetamine (MDMA) has seen a resurgence and an evolution over the last 10 years. The once-popular variety called Ecstasy has given way to Molly, which is supposedly both purer and safer than its predecessor. 

But the thing about illegal drugs is that, well, they're illegal, which means they're unregulated, which means there's no formalized quality control or consumer protection. You can't know for sure what you're getting. This could mean that the drug fails to get you high. It could also kill you. 

Looking at this problem, behavioral scientists at Johns Hopkins University had two questions: First, if party drug users had a way to check their drugs, would they do it? And second, what would they find?

To find out, the researchers teamed up with the nonprofit DanceSafe, which aims to make the electronic-music scene a safer place. Part of that work involves on-site adulterant screening, better known as pill testing. DanceSafe volunteers bring a mobile lab to a festival or other event and offer attendees cost-free, judgment-free chemical analysis of their pills and powders. 

Over a five-year period between 2010 and 2015, DanceSafe volunteers collected and tested 529 samples of drugs sold as MDMA. To test them, they scraped a tiny sliver or a few grains into a vial, and then mixed it with color-changing chemicals. The testers then compared the resulting color inside the vial with the color-test profile of 29 different substances, including MDMA, sugar, caffeine, and cocaine. 

Unsurprisingly, the results were not great. About 40 percent of the samples contained no MDMA at all and had been adulterated. The most common substitutes included methamphetamine and the compounds called "bath salts." Three samples included the amphetamine called PMA, which has been strongly linked to overdose and death. And the pills sold as Molly were no safer or purer than those sold as Ecstasy.

After sharing the results of a pill test, DanceSafe volunteers typically ask each person if they still intend to take the drugs. Only 26 percent of people with adulterated pills said they did. Interestingly, that number was only 46 percent for people whose MDMA was real—which suggests that the test itself may have caused them to reconsider.

"Our results suggest that some people will reject taking a pill to get high if it doesn't contain what they thought it did, or has harmful additives," corresponding author Matthew W. Johnson said in a statement.

Because their plans were self-reported, it's hard to know for sure what any of these people actually did next. They might have taken the drugs anyway, given them away, or sold them.

Judgment-free pill testing is not without controversy, and it's hard to design controlled experiments when illegal substances are involved. Still, the researchers say, these findings should give us pause.

"People would be safest not taking any street drugs at all," Johnson said. "But if free, no-fault testing can reduce deaths and other catastrophic consequences, it may be a service worth having."

Johnson and his colleagues urge would-be MDMA users to think hard about these findings: "People who take pills and first responders need to know that no matter how the pills are branded or what name they are sold as, they almost always contain a mix of ingredients."