If you’ve heard of psilocybin therapy, you’ve heard of COMP360. It’s the compound behind almost every major headline on this topic in the past few years. Anyone living with treatment-resistant depression and watching this space closely will also want to know what COMP360 exactly is, what the trials have found, and how close it really is to becoming something you could be prescribed.
What Is COMP360?
COMP360 is a proprietary, pharmaceutical-grade formulation of synthetic psilocybin, developed by the company Compass Pathways specifically for treatment-resistant depression. It isn’t mushrooms, and it isn’t something available at a dispensary or wellness retreat. It’s an investigational drug moving through the same regulated clinical trial process any new psychiatric medication has to go through.
In every trial so far, COMP360 has been administered as a single capsule, taken during a supervised, multi-hour session with trained support present, following a preparatory meeting and followed by structured integration sessions afterward. The drug and the surrounding therapeutic process are tested together, not separately, which matters for understanding what the results below actually represent.
The Trial Results, Step by Step
There have been three major trials so far. Here’s what each one found.
- Phase 2b (2022): This was the study that put COMP360 on the map. Published in the New England Journal of Medicine, it compared three doses (25 mg, 10 mg, and 1 mg) in 233 participants with treatment-resistant depression. Only the 25 mg dose produced a statistically significant reduction in depressive symptoms at three weeks compared to the 1 mg control, while the 10 mg dose did not clearly separate from the control group.
- Phase 3, COMP005 (2025): This was the first of two pivotal trials needed to support an FDA application. It tested a single 25 mg dose against a low-dose comparison and met its primary endpoint, showing a statistically significant reduction in depression severity at six weeks.
- Phase 3, COMP006 (2026): The second pivotal trial took a different approach, testing two 25 mg doses given three weeks apart. It also met its primary endpoint at six weeks, and in follow-up data released mid-year, the improvement held through 26 weeks for people who had responded to treatment, which is the longest follow-up window reported for COMP360 so far.
The caveat here is that most of the phase 3 results have been shared through company announcements instead of full peer-reviewed publications, which is standard practice ahead of a regulatory filing. That means independent researchers haven’t yet had the chance to scrutinize the complete data.
What We Know About the Safety of Psilocybin Therapy
Across these trials and the broader body of psilocybin therapy research, side effects have generally been short-lived and manageable under supervision. They include nausea, headache, and transient anxiety during the dosing session, along with temporary increases in blood pressure and heart rate. Serious adverse events have been uncommon.
The bigger caveat is what we don’t know yet. COMP360 is still an investigational drug, which means no formulation of it has been on the market long enough to generate the kind of long-term safety data we have for decades-old antidepressants.
The longest follow-up reported so far is 26 weeks, which says something about durability of response but little about what repeated or long-term use might look like over years. How COMP360 interacts with other medications is also not fully mapped out. Trial participants are carefully screened and often tapered off other psychiatric medications beforehand, which is a controlled situation different from how depression is typically treated in practice, where people are frequently on more than one medication at a time.
But this doesn’t mean the drug is unsafe. It just means the safety picture, while encouraging so far, is still being filled in, in the way it is for any new psychiatric medication at this stage.
Where COMP360 Stands With FDA Regulators
This is the part people most want a straight answer on, so here it is: COMP360 is not approved anywhere yet, and psilocybin remains a Schedule I controlled substance in the United States.
That said, momentum has picked up.
- Rolling review: Compass Pathways has been working with the FDA through a rolling review process, meaning the agency reviews completed sections of the application as they’re finished instead of waiting for the full package.
- Priority voucher: In April 2026, the FDA granted COMP360 a Commissioner’s National Priority Voucher, meant to compress the standard review timeline down to one to two months once the complete application is submitted
- Filing timeline: The company expects to finish its submission in the fourth quarter of 2026
- DEA rescheduling: Even with FDA approval, psilocybin would still need to be reclassified out of Schedule I before it could legally be prescribed
- Projected launch: Compass has suggested a possible U.S. launch in the first half of 2027 if everything proceeds on this timeline, but that’s merely a projection, for now.
What This Means If You’re Living With Treatment-Resistant Depression
It’s easy to read trial coverage like this and feel caught between hope and frustration. Hope that something this promising exists, frustration that it isn’t available yet for the depression you’re dealing with today. Both reactions are understandable, and so is having mixed emotions.
COMP360 represents real progress in a field that hasn’t had much of it, and it’s also, realistically, at least a year away from being something a doctor could prescribe, if it’s approved at all.
That gap is exactly why you should know what’s already available. Ketamine and its FDA-approved derivative esketamine (Spravato) are psychedelic treatments that work through a related but distinct mechanism, have years of real-world clinical use behind them, and don’t require waiting on a regulatory process to find out if they’ll help.
Talk to Someone Who Can Walk You Through the Options
You don’t have to choose between watching COMP360’s progress and doing something about how you feel right now. Book your free consultation, and the Kadelyx team can talk through your history, answer your questions about where psilocybin research actually stands, and explain what ketamine-assisted treatment could look like for you in the meantime.
