If you have, you are either living in South Korea, or lying, or possibly both. Derbisol is rarely discussed now, but at one point it was supposed to be the drug that caught out the kind of people who lie about taking drugs.
Derbisol is a debatable urban legend. Exactly what it is, and how it's used, is a mystery to most, including the people who are supposed to have used it. It gained fame when it was revealed as a drug that people sometimes add to a list of drugs in surveys to ascertain widespread drug use. After seeing survey after survey of teens that showed that the kids were taking everything they could get their hands on every day of the week, it occurred to researchers that that maybe kids weren't avatars of chemical depravity. Maybe they were just liars.
One research group proposed adding a fictitious drug to the list of real ones, and asked kids if they did that drug. Derbisol (which appears at least now to be an actual drug in Korea), was added, and a few fanciful street names, like DB and Derbs, were made up. In the end, a little over 18 percent of kids said they had used a fictitious drug. That wasn't all they (weren't) doing. The Derbisol group had a much higher rate of reported drug use than the non-Derbisol group for all drugs.
Since then, Derbisol seems to have become a parallel legend. It's got out that it's a fictitious drug, and other fake drugs have subsequently been invented. At the same time, it seems to have gotten a minor street reputation. One teacher wrote about her students taunting her with the necessarily-sketchy details of what Derbisol is and how one did it, which made her dig until a healthcare worker let her in on the secret. It's a clever idea, at least. Perhaps it could be pushed even further. There must of been kids who were lying about some of their experiences with drugs but didn't happen to lie about Derbisol. I wonder how a list of half-real, half-fake drugs would come out.