Psilocybin and neuroplasticity: what the science says

Neuroplasticity is the brain’s ability to reorganise itself: to grow new connections, strengthen useful ones and let others fade. Over the last few years it has become one of the most active areas of psychedelic research, because several studies suggest that psilocybin, the compound found in Psilocybe cubensis, may influence exactly these processes.

This article summarises what the research actually shows, separating solid laboratory findings from early human data and from the claims that often circulate online. It is an informational overview of published science, not medical advice or a guide to use.

What is neuroplasticity?

Neurons communicate through junctions called synapses. Many of these sit on dendritic spines, tiny protrusions on the branches of a neuron. When spines form, grow or disappear, the brain is literally rewiring itself. This is the physical basis of learning, memory and adaptation.

Researchers are interested in this because conditions such as chronic stress and depression have been associated with a loss of these connections in areas like the prefrontal cortex. Anything that can promote healthy plasticity is therefore of great scientific interest.

How psilocybin acts on the brain

Psilocybin itself is a prodrug: the body converts it into psilocin, which acts mainly on serotonin 5-HT2A receptors. These receptors are densely present in the cortex and are responsible for the perceptual effects of psychedelics. If you want to understand the difference between the two molecules, read our article on psilocybin vs psilocin.

The interesting question for plasticity researchers is what happens beyond those immediate effects, in the days and weeks that follow.

What the laboratory studies show

New dendritic spines in mice

In 2021, a team at Yale published a study in Neuron showing that a single dose of psilocybin in mice increased the number and size of dendritic spines in the frontal cortex by about 10%. Part of that growth was still present a month later. The study is summarised in this Yale News article.

A direct link with BDNF

In 2023, researchers led by the University of Helsinki reported in Nature Neuroscience that psychedelics, including psilocin, bind directly to TrkB, the receptor for BDNF (brain-derived neurotrophic factor), a key molecule in plasticity. According to the authors, this binding was much stronger than that of conventional antidepressants and appeared to be separate from the hallucinogenic effect. The full paper is available on PubMed Central.

What we know in humans

Measuring spines in living human brains is not possible, so human studies look at brain networks instead. In 2024, researchers at Washington University published in Nature a precision brain-imaging study in which psilocybin strongly “desynchronised” brain networks, especially the default mode network, which is involved in self-referential thinking. Most changes returned to normal within days, but a reduced connection between the hippocampus and the default mode network lasted for weeks. You can read the university’s summary here.

Researchers interpret this temporary “loosening” of networks as a window in which the brain may be more flexible, which could help explain why psilocybin is being studied in clinical settings together with psychotherapy.

Psilocybin in clinical research in Europe

Psilocybin-assisted therapy is being investigated in clinical trials for conditions such as treatment-resistant depression. In Europe, the Czech Republic became the first EU country to allow its therapeutic use: since 1 January 2026, psilocybin can be used in treatment under strict medical conditions. The Czech National Institute of Mental Health explains the framework in this official statement.

Outside these regulated settings, psilocybin remains a controlled substance in most European countries, so it is important to check the laws where you live.

What neuroplasticity research does not show (yet)

• Mouse results are not human results. Spine growth has been demonstrated in animals; in humans, we only see indirect signals in brain networks.
• More plasticity is not automatically better. Plasticity can reinforce helpful or unhelpful patterns depending on context, which is why clinical studies combine psilocybin with therapy and supervision.
• Small doses have not been shown to produce the same effects. Controlled studies on microdosing have found effects similar to placebo, as we explain in our article on microdosing psilocybin and what the science says.

Why this matters for mycology

All of this research depends on well-characterised material: known species, documented genetics and laboratory analysis. That is the same approach we follow at MycoBag with documented Full Canopy Genetics cultivars, which you can explore in our elite mushroom genetics guide, and with MycoTest, our laboratory analysis service for mushroom samples.

Frequently asked questions

Does psilocybin create new neurons?

The studies mentioned show new connections (dendritic spines) between existing neurons in mice, not the creation of new neurons.

How long do the changes last?

In mice, part of the spine growth lasted at least a month. In humans, most network changes normalised within days, with some changes lasting weeks.

Is psilocybin legal for therapy in Europe?

Only in specific regulated frameworks, such as the Czech Republic since 2026. In most European countries it remains a controlled substance.

This article is for informational and scientific purposes only and does not constitute medical advice.