A first-of-its-kind study has found evidence that microdosing LSD may help to manage pain. The study, which was led by researchers from the Netherlands’ Maastricht University and the University of Basel in Switzerland, lends some new empirical credence to theories first explored in the 1960s by psychedelic researcher Eric Kast, who administered LSD to 300 patients, most in the throes of pre-terminal cancer, in 1965.

As reported in JAMA, Kast said results were both “encouraging and puzzling.” “Encouraging — because LSD relieves pain much longer than other drugs; puzzling — because many of the patients declined a second administration.” 

Unlike this 1960s experiment, the new study in Maastricht was much different in that it involved microdosing LSD for pain. When you microdose LSD, you take minute amounts of the drug—certainly not enough to induce a trip.

Here’s how the study was conducted: On four separate days, the 24 participants received either a placebo or varying doses of LSD — 5, 10, and 20 micrograms — each day. An hour and a half after microdosing LSD (or a placebo), the subjects had their pain tolerance tested using a Cold Pressor Test, and they were tested again 5 hours after administration. 

In a Cold Pressor Test, subjects immerse their hands into extremely cold water — a few degrees above freezing, in this case. Subjects let the researchers know when they start feeling pain in the water and then pull their hand out when the pain becomes unbearable. The longer you can keep your hand in, the stronger your pain tolerance apparently is.

The researchers found that, when participants received the 20 microgram dose, the drug appeared to “significantly increase the time that participants were able to tolerate exposure to cold (3°C) water and decreased their subjective levels of experienced pain and unpleasantness,” compared to how they did on the other doses and placebo. The effect persisted for at least five hours after the microcode, too.

So, what does this tell us?

Back in 1964, Kast theorized that the LSD distracted people from the pain, but in this study, the LSD was microdosed and thus no one tripped. The modern-day researchers offered a couple of theories, including LSD hitting brain receptors that mitigate pain, or triggering something called hypertension-associated hypoalgesia, wherein high blood pressure can lessen pain.

With that said, the sample data is still too small, and more research must be done before any big conclusions can be made about LSD’s ability to reduce pain.