New Study Suggests Microdosing May Be a Macro Placebo Effect

A study suggests psychedelic microdosing may have mostly to do with expectations

Posted Mar 03, 2021 | Reviewed by Gary Drevitch

  • A new study of psychedelic microdosing found that many of the beneficial effects of the practice may be due to the placebo effect.
  • The research was based on a "citizen science" approach, recruiting people who were already microdosing.
  • Many participants reported having intense spiritual experiences on the placebo.

Oh, microdosing, the psychedelic equivalent of tapas. For years, microdosing has been creating a macro-hype. Interest has ballooned with “microdose coaches” charging massive prices and how-to articles on microdosing your dog

But a new, groundbreaking study by Imperial College in London has shown that a majority of the effects felt by microdosing can be explained by the placebo effect. This most recent microdosing study is a peer-reviewed study that uses blind control groups instead of anecdotes. While its findings join a litany of articles skeptical of the effects of microdosing, this study is unprecedented in its comprehensiveness. 

Psychedelics are difficult to study because, to put it politely, most governments don’t like them. So in this London-based experiment, researchers used a “citizen science” approach to study 191 participants over four weeks. Participants who were already planning to microdose psychedelics, specifically LSD or psilocybin, were instructed on how to create placebo pills and randomize their doses based on envelopes labeled by QR codes. Participants were randomly assigned to a microdosing group, a placebo group, and one group that received a half dose. 

For long-term effects, all groups had significant improvements in mindfulness, and a decrease in paranoia. However, there was no difference in the placebo versus the microdosing group, implying the improvement was mostly likely due to the placebo effect. 

Over the short term, the microdosing group had significantly higher scores for acute drug intensity and improved scores for acute emotional state, mood, energy, and creativity. In the tests taken several days after the dose, the microdosing group had reduced anxiety compared to the placebo group.

When researchers compared people based on what they believed they had taken, 21 out of 22 of their tests were significantly different — with the group who thought they had a microdose always performing better). However, when they compared people based on what they actually took, all of the differences disappeared except one: the measurement of drug intensity.  

This just goes to show that the positive effects of microdosing may have been primarily due to the expectation and belief of positive effects, rather than to the substances themselves.

Is microdosing the new “homeopathy”?

For starters, there’s a paradox: The actual doses within a microdose regimen have been defined as “sub-perceptual.” Yet the reasons for microdosing are. . .perceptual. Subsequently, microdosers may be easily manipulated by self-appointed experts since the users themselves have a hard time accurately perceiving the effects.

There may be suspect motives behind the trendiness of microdosing. One possibility is that proponents are trying to shoehorn psychedelics into a pharmaceutical model. Taking a drug every day is a familiar routine for SSRI users. But psychedelic-assisted therapy is not a daily occurrence. Second, microdosing seems predominantly aimed at improving productivity rather than mental well-being, which, while a relatable goal, may not be the best application of psychedelics. 

While microdosing is likely benign if not ineffectual, there may be some negative behavioral impacts. Microdosing protocols put less emphasis on “set and setting.” While macro-dosing involves preparation of mindset (set) and environment (setting), microdosing seems more likely to take place in an office on a Tuesday morning than at a weekend retreat in a psychedelic ceremony. 

That said, microdosing certainly sounds more cost- and time-effective. Without a guru and in the short term, what a bargain!

There is room for argument. The placebo effect did not explain the entirety of the positive effects of microdosing, just a majority. The study did find a small positive effect of microdosing over the placebo group which was not statistically significant; however, it could potentially be significant in a larger study with greater statistical power. The study group also skewed very young and came into the experiment with very positive expectations of microdosing. Perhaps the long-term benefits of microdosing are felt after the nine-week survey used in this study. Finally, a placebo is not nothing. The users’ expectations of the benefits of psychedelics come from rigorous studies of macro doses and many participants reported an intimate knowledge of these studies. Just because the results were psychosomatic does not mean the effects weren’t real. In fact, many participants in this study reported having intense spiritual experiences on the placebo, and were shocked to find out they had not taken the microdose.

Overall, whether microdosing wins or loses public approval, this study is a win for psychedelic science. For decades, LSD was administered in back alleys in sugar cubes. Now LSD placebos are measured in sugar pills and written about in mainstream publications. Perhaps, we can only appreciate this bigger picture with a smaller dose.


‘Self-blinding citizen science to explore psychedelic microdosing’ by Szigeti, B. et al. is published in eLife. DOI: 10.7554/eLife.62878