 at the most popular psychedelic. The runner-up was MDMA or ecstasy at just over one percent, followed closely by LSD. Half of people who took mushrooms said they chose to microdose. Dr. Joshua Woolley, a researcher at UCSF, says microdosing is increasingly popular, but much of the evidence on psychedelics is based on people taking much larger doses while also receiving therapeutic support. We don't actually know that much about microdosing.