What is afterglow after psychedelics and how to utilize the window of neuroplasticity

Days after a psychedelic experience are often described as exceptional: a sense of clarity, lightness, and peace that is hard to reach by other means. This is not just a subjective report. A systematic review of 48 studies involving 1774 people described this state as a repeatable subacute phenomenon, measured from one day to a month after taking the substance. Concurrently, studies on rodents have shown that after a psychedelic, a temporary window of increased brain plasticity opens, and its length depends on how long the acute effects lasted. This text gathers what is known about this window from research: how long it lasts, what it is biologically based on, and which actions have documented foundations and which remain hypotheses.

KEY INFORMATION
• Afterglow was described in a review of 48 studies involving 1774 people, in a window from one day to a month after the session (Evens et al., Therapeutic Advances in Psychopharmacology, 2023).
• In mice, the plasticity window lasted 48 hours after ketamine and two weeks after psilocybin (Nardou et al., Nature, 2023).
• Psilocybin and psilocin are in Poland in group I-P of the list of psychotropic substances.
• The text describes clinical studies and does not encourage the use of controlled substances.

What is afterglow after psychedelics?

Afterglow is a subacute state that persists after the acute effects of the substance have subsided: reduced intensity of psychopathological symptoms with increased indicators of well-being, mood, and mindfulness. A systematic review by Evans and colleagues included 48 studies and 1774 participants, and the analyzed window covered the time from one day to a month after taking the substance (Evens et al., Therapeutic Advances in Psychopharmacology, 2023).

This same review organizes what exactly changes. A consistent increase in well-being, mood, mindfulness, social measures, and spirituality, as well as positive behavioral changes, was reported. Changes in personality and values, as well as changes in attitudes and creativity, were mixed, meaning they appeared in some studies and not in others. This distinction has practical significance: mood and social openness are much better documented during this period than the alleged leap in creativity.

It is worth separating afterglow from the pharmacological action itself. In a randomized study by Davis and colleagues, 27 people with major depression were randomly assigned to immediate or delayed therapy, and 24 completed the analysis. The score on the QIDS scale dropped from an average of 16.7 points before treatment to 6.3 days after the first session and remained reduced in the fourth week (Davis et al., JAMA Psychiatry, 2021). The substance had long been eliminated by then, yet the effect persisted.

How long does the neuroplasticity window last?

The hardest data on the length of this window comes from studies on mice. The Nardou team showed that psychedelics reopen a critical period for learning social rewards, and the opening time is proportional to the length of the acute subjective effects described in humans (Nardou et al., Nature, 2023).

Measured times varied significantly between substances. After ketamine, the window was open for 48 hours and closed after a week. After psilocybin, it remained open in the first and second weeks, but not in the third. After LSD, it lasted until the third week, and after ibogaine, it was still open in the fourth. Increasing the dose of LSD did not extend this time, which argues against a simple dose-to-duration conversion.

The conceptual framework for these observations was described by Lepow, Morishita, and Yehuda: the psychedelic would remove the brakes on adult brain plasticity and put it in a state similar to a developmental critical period (Lepow et al., Frontiers in Neuroscience, 2021). We noticed that popular texts transfer numbers from mice directly to humans. No one has measured this window in humans yet, so the weekly ranges given online are extrapolations, not measurements.

What does BDNF have to do with afterglow?

BDNF is a growth factor supporting neuron survival and synapse formation, and its receptor TrkB is one of the pathways through which psychedelics act. The Ly team showed that serotonergic psychedelics increase the growth of neurites and dendritic spines in cultures and in animals, and these changes occurred through the TrkB, mTOR, and 5-HT2A pathways (Ly et al., Cell Reports, 2018).

Precision is needed here, as a shortcut circulates online in a distorted form. The Ly study did not measure BDNF levels in the blood nor prove that the psychedelic raises its level. It showed that the signal goes through the receptor of this protein, and the structural effect is comparable to ketamine. We describe this pathway more broadly in the entry about the 5-HT2A receptor and brain plasticity.

Physical exercise affects the same system, and here the data comes from humans. A meta-analysis by Szuhany and colleagues included 29 studies and 1111 participants. A single session of exercise resulted in a moderate increase in BDNF (Hedges g equal to 0.46), regular training strengthened the effect of a single session (g equal to 0.59), and resting BDNF levels increased slightly (g equal to 0.27) (Szuhany et al., Journal of Psychiatric Research, 2015). The cannabinoid context of the same signaling is gathered in our entry about neuroplasticity and BDNF.

What to do in the afterglow window to solidify the effect?

The short answer is: there are fewer practices with strong evidence in this window than guides suggest. The best-documented is the quality of the therapeutic relationship, followed by aerobic exercise acting on the same pathway, and one popular practice, microdosing, did not differ from placebo in a self-blinding study.

The study by Smigielski deserves a separate mention, as it is often cited inaccurately. It involved 38 people who took psilocybin during a five-day meditation retreat. The disconnection of the medial prefrontal cortex and the posterior cingulate cortex was associated with a sense of ego dissolution, and the intensity of this phenomenon along with brain connectivity predicted improvement in psychosocial functioning four months later (Smigielski et al., NeuroImage, 2019). The default mode network is described more broadly in our entry about DMN and afterglow.

Why does integration weigh more than the session itself?

Because it is most strongly associated with the final outcome. In the psilocybin arm of a randomized study comparing psilocybin with escitalopram, 30 people received two doses of 25 mg spaced three weeks apart, with preparation, support during the session, and integration therapy afterward.

The strength of the therapeutic alliance predicted the quality of contact before the session, the intensity of emotional breakthrough and mystical experience, and the final outcome on the QIDS scale. More importantly, the quality of the relationship before the second session influenced the final intensity of depression directly, bypassing the experience itself: a weaker alliance predicted a higher depression score at the end of the study (Murphy et al., Frontiers in Pharmacology, 2021).

We noticed that popular guides reverse this dependency and attribute the durability of the effect to the intensity of the experience. The data suggest something more cautious: intensity mattered, but it was itself predicted by the relationship with the facilitator. The practical consequences are described in our entry about integration step by step. It is also worth remembering that all these observations come from clinical conditions, with preparation, supervision, and planned post-session care, not from home situations.

Can afterglow be difficult and what does Polish law say?

It can be. The review by Evens also gathered adverse effects from the same window: headaches, sleep disturbances, and isolated cases of increased psychological distress. The authors classified them as mild to severe, with no serious events recorded, and many studies did not conduct standardized assessments of such effects at all.

Participant selection limitations say more here than safety declarations. In the Davis study, individuals with a history of psychotic disorders, serious suicide attempts, or psychiatric hospitalization were excluded, and participants did not take antidepressants during this time. The results therefore concern a selected, prepared population led by a clinical team, not the average reader reaching for a description of such a window online.

The legal status in Poland is unequivocal. Psilocybin is listed under item 86, and psilocin under item 76 of the list of psychotropic substances in group I-P. These are therefore controlled substances, and their possession and trade are prohibited. The studies described in this text were conducted in centers operating under separate permits, and transferring their protocols outside this context is neither legal nor safe.

Frequently Asked Questions

What is afterglow after psychedelics?

It is a subacute state after the acute effects of the substance have subsided, with reduced intensity of psychopathological symptoms and increased well-being, mood, and mindfulness. A review of 48 studies involving 1774 people measured it in a window from one day to a month after taking the substance (Evens et al., 2023).

How long does the neuroplasticity window last after a psychedelic?

In mice, the window remained open for 48 hours after ketamine, two weeks after psilocybin, three weeks after LSD, and four weeks after ibogaine (Nardou et al., Nature, 2023). No one has measured the length of this window in humans yet, so the given ranges are extrapolations.

Does microdosing extend afterglow?

There is no data on this. The largest study with self-blinding involved 191 people, and all psychological outcomes improved in the placebo group as well, with no significant differences between groups (Szigeti et al., eLife, 2021). The authors explain the effect by expectation.

Do psychedelics increase BDNF levels?

The Ly study did not measure BDNF levels, but showed the growth of neurites and dendritic spines occurring through the TrkB, mTOR, and 5-HT2A pathways (Ly et al., Cell Reports, 2018). TrkB is the BDNF receptor, so it is about signaling, not a proven increase in concentration.

Can afterglow be unpleasant?

Yes. Headaches, sleep disturbances, and isolated cases of increased psychological distress were reported in the same window, rated as mild to severe, with no serious events recorded (Evens et al., 2023). Many studies did not use standardized assessments of such effects.

Is psilocybin legal in Poland?

No. Psilocybin is listed under item 86, and psilocin under item 76 of the list of psychotropic substances in group I-P. These are controlled substances, and their possession and trade are prohibited in Poland. Clinical studies are conducted only by centers operating under separate permits.

This article is for informational and educational purposes. It describes clinical studies in which the substance is administered under medical supervision after participant qualification; using these conditions on one’s own does not replicate them. These substances are controlled in Poland under the Act on Counteracting Drug Addiction. If you have suicidal thoughts, call the free, 24-hour numbers 116 123 or 800 70 2222. In case of life-threatening situations: 112.

Author: Michał Waluk · Published: 2026-08-09 · Updated: 2026-08-11