A new trial studying the effects of micro-dosing with psychedelics begins this week.
Micro-dosing involves taking around a 10th of a recreational amount, such as 10 to 20 micrograms of LSD, to improve psychological wellbeing and cognitive function.
At this low intake level, the psychedelic effects of these drugs cannot be perceived.
Some users say taking 10-20 micrograms at a time improves mood and creativity, and this is the first study to test whether those effects go beyond placebo.
The Beckley Foundation trial will use a "self-blinding method" on participants who already micro-dose.
Participants will create their own capsules of psychedelic micro-doses, and then put these pills - as well as placebos provided by the researchers - in unlabelled envelopes to take at random.
The envelopes will have barcodes so researchers can monitor whether a participant is taking a psychedelic or a placebo on any given day.
The effects will be tracked by online questionnaires and a series of cognitive tests.
This is the first trial of its kind, as it is the first trial on the effects of micro-dosing that involves a control element.
However, as it is a non-traditional controlled trial, researchers say the findings will only be somewhat reliable, though still helpful.
In recent years, micro-dosing with psychedelics has become popular in Silicon Valley, with the goal of boosting productivity.
Many indigenous cultures around the world have used psychedelic plants such as peyote and magic mushrooms for centuries.