Scientists Say a Week of Meditation Can Change Your Brain in Ways That Rival Psychedelics
You'd think meditating, something that people have been doing for thousands of years, would be fully understood. Yet for decades, scientists have struggled to explain exactly how it changes the body. That mystery is finally unraveling thanks to a groundbreaking study published in Communications Biology, where researchers at the University of California, San Diego, unpacked some of the strongest evidence yet. Researchers discovered that just one week of intensive meditation can trigger changes in brain activity, immune function, and metabolism. Most surprisingly, the brain changes look a lot like what you see with psychedelic drugs.
The study tracked 20 healthy adults during a week-long retreat filled with 33 hours of guided meditation, lectures, and group healing. By comparing fMRI brain scans and blood samples from before and after the week, they could see exactly what changed.
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What Changed in the Brain and Body
The changes were pretty wide-ranging. Brain imaging showed less activity in regions tied to mental chatter, a sign of more efficient brain processing. Blood tests showed a spike in natural pain-relieving chemicals (endogenous opioids) and signs of a more balanced and adaptive immune response. There were also elevated neuroplasticity markers, hinting at new connections forming in the brain.
Participants also reported intense feelings of unity, transcendence, and expanded awareness, all classic hallmarks of a mystical experience. The deeper the experience people reported, the more dramatic their biological changes tended to be.
Why Researchers Are Comparing This to Psychedelics
What the researchers saw from the brain connectivity patterns after the retreat looked a whole lot like patterns that have been linked to using psychedelics like psilocybin (the active compound in magic mushrooms).
Clinically, this makes a lot of sense. Jennifer Lancaster, LCSW-S, a therapist at Houston Healing Collective who uses both meditation and ketamine-assisted therapy, says the overlap isn't surprising given what's already known about how both practices affect the brain. While meditation research usually looks at people who have practiced for years, she says psychedelics are exciting because they seem to fast-track those same brain changes, which can lead to powerful healing and growth.
"What it does tell me is that intensive, immersive formats are worth taking seriously," she says.
Both practices likely work by quieting the brain's default mode network, a web of brain regions that can keep us stuck in repetitive loops of overthinking and self-criticism. By turning down the volume on this inner chatter, meditation and psychedelics both help the brain be more flexible and open to new ways of thinking.
What This Study Can and Can't Tell Us
Before reading too much into these findings, it's worth flagging some limitations.
Small, biased sample: The study only included 20 people, and they were all self-selected, meaning they had already decided to attend the retreat and had already likely bought into the practice. This kind of self-selection bias makes it hard to rule out that people are expected to feel better (expectancy effects). It's also worth noting that the retreat itself was led by Joe Dispenza, who is also an author on the paper, so he has a biased interest in the outcomes.
No control group: There was no randomized control group to compare against, so it's essentially impossible to separate the effects of the intensive meditation from whatever changes happened just from spending a week in a supportive group, listening to lectures, and taking time off from daily life.
Contradictory findings in more rigorous research: Another major, highly rigorous study, which combined two randomized controlled trials with 218 participants, found no detectable changes in brain structure (no gray matter growth or cortical thickening) after eight weeks of mindfulness-based stress reduction (MBSR).
None of this means meditation is useless, and the benefits of lowering stress, improving emotional regulation, and focus do have plenty of other research to back them up. Plus, there were real blood markers and brain connectivity changes; it's just tricky to determine the actual cause.
Who Benefits and Who Should Be Cautious
Meditation practices like these are ideal if you're stressed, anxious, or have a low mood or chronic pain, says Dr. Clint Salo, a board-certified psychiatrist at The Grove Recovery Community. But if you're experiencing active psychosis, mania, or severe dissociation, it may not be safe or useful.
Lancaster agrees with that concern from her own practice. "The question I ask is: does this person have enough stability to tolerate what might come up?" she says. Intensive meditation has a way of surfacing buried emotions and memories, which can be helpful if you have the right support, but it can overwhelm someone whose nervous system isn't ready for it.
How to Start Meditating Without a Week-Long Retreat
Of course, we don't all have access to a seven-day retreat, but you probably don't need to, either. Salo recommends starting with about 10 minutes a day of simple breath-focused meditation.
"Focus on steady breathing, notice when attention drifts, and gently return without judgment," he says.
In the end, the best meditation routine is the one you'll actually do today, tomorrow, and the day after that, says Lancaster. According to Lancaster, most people start seeing the benefits, like better sleep or more emotional control, after about three or four weeks of consistency.
"A small practice you return to every day will reshape your nervous system in ways that an ambitious one you abandon in a week never will," she says.
Your Brain Doesn't Need a Trip
This study won't settle the debate over meditation vs. psychedelics, and it isn't trying to. What it does show is that some intensive meditation can make a big impact on your brain and body, and some of those changes look a lot like what psychedelics can do. For most men, practicing meditation every day, even for just 10 minutes, is a worthy investment. You don't need a retreat, prescription, or trip to change how your brain handles stress. You just need to show up and sit with it.
This story was originally published by Men's Journal on May 15, 2026, where it first appeared in the Health & Fitness section. Add Men's Journal as a Preferred Source by clicking here.
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This story was originally published May 15, 2026 at 10:04 AM.