People interested in learning what's really in the drugs they bought (or manufactured) can send a sample to Energy Control in Barcelona, Northern Spain. This lab will check for adulterants and purity levels of MDMA, speed, cocaine, and other drugs.
From Grace Caffyn's CoinDesk story, "Inside Barcelona's Bitcoin Drug Lab":
Energy Control has been carrying out drug checking in raves and at its labs since 1998. Its dark web service, introduced in April 2014, operates under the same premise: to reduce harm among users by arming them with facts.
The idea for the project can be traced back to a family physician named Fernando Caudevilla, commonly known as Dr X. Following his first post to the Silk Road forum in April 2013, six months before the market's FBI shutdown, he became a trusted source of guidance on drug safety across many dark markets.
Up until this point, Energy Control, which is over 90% government funded, had only offered services inside Spain. However, Caudevilla – who has worked with the organisation since 2000 – saw the potential for a drug checking service for the dark web – completely anonymous, of course.
Previously: Inside the Deep Web Drug Lab