Psychoactive Substance Encyclopedia

Kratom (*Mitragyna speciosa*) is a tropical evergreen tree in the coffee family (Rubiaceae), native to the rainforests of Thailand, Malaysia, Indonesia, Myanmar, and Papua New Guinea. For centuries, Southeast Asian laborers, farmers, and fishermen have chewed its dark, glossy leaves or brewed them into tea to fight fatigue, dull the aches of physical labor, and lift their spirits through long working days. In the West, kratom has exploded in popularity since the 2000s, becoming one of the most widely used unregulated psychoactive botanicals in the United States, with an estimated 10 to 16 million regular users as of 2024. What makes kratom pharmacologically fascinating is its dose-dependent duality. At low doses (1-3 grams of dried leaf), it behaves like a stimulant: users describe increased energy, improved focus, and a warm sociability reminiscent of a strong cup of coffee but with a distinctly euphoric edge. At higher doses (5-8+ grams), the experience shifts decisively into opioid territory: pain relief, sedation, and a thick, contented warmth that users compare to low-dose hydrocodone. This dual personality arises from the complex receptor pharmacology of its primary alkaloids, mitragynine and 7-hydroxymitragynine, which act as partial agonists at mu-opioid receptors while also engaging adrenergic and serotonergic systems. Kratom is the only plant besides the opium poppy (*Papaver somniferum*) known to produce alkaloids that activate mu-opioid receptors. But unlike classical opioids, mitragynine is a partial agonist with G-protein biased signaling, which appears to create a ceiling effect on respiratory depression -- the mechanism responsible for the vast majority of opioid overdose deaths. This pharmacological distinction is central to the fierce debate surrounding kratom: advocates point to its potential as a harm reduction tool for people managing chronic pain or transitioning away from more dangerous opioids, while regulatory agencies like the FDA have raised concerns about dependence, product contamination, and the lack of quality control in the unregulated market. The political landscape around kratom is remarkably active. The DEA attempted to schedule kratom in 2016 but withdrew its proposal after over 140,000 public comments and a letter from 51 members of Congress -- the first time the agency had ever reversed a scheduling action due to public opposition. As of 2026, kratom remains federally unscheduled in the US, though six states ban it outright and over 20 have enacted Kratom Consumer Protection Acts to regulate rather than prohibit it. Meanwhile, Thailand re-legalized kratom in 2021 after decades of prohibition, granting amnesty to over 12,000 previously convicted individuals.

Psilocybin mushrooms — known colloquially as magic mushrooms, shrooms, or simply mushies — are fungi containing the psychedelic tryptamines psilocybin and psilocin. Over 200 species across multiple genera produce these compounds, with *Psilocybe cubensis* being the most widely cultivated and *Psilocybe semilanceata* (liberty caps) the most commonly encountered wild species in temperate climates. Upon ingestion, psilocybin is rapidly dephosphorylated into psilocin, which acts as a partial agonist at serotonin 5-HT2A receptors, producing profound shifts in perception, emotion, and cognition that typically last four to six hours. What sets psilocybin mushrooms apart from synthetic psychedelics is their character. Users consistently describe the experience as warmer, more emotionally textured, and more "organic" than LSD or research chemicals. The mushroom trip tends to feel like a conversation — sometimes gentle, sometimes confrontational — rather than a ride. This quality has made them central to spiritual and ceremonial use for thousands of years, and it is part of why the modern psychedelic research renaissance has placed psilocybin at its center. The clinical data is now substantial. Landmark trials at Johns Hopkins, NYU, and Imperial College London have demonstrated significant, lasting antidepressant effects from just one or two supervised psilocybin sessions. A 2024 dose-response meta-analysis of randomized controlled trials confirmed psilocybin's efficacy for major depressive disorder, including treatment-resistant cases. Over 134 clinical trials are now registered on ClinicalTrials.gov across 54 potential therapeutic indications — depression, end-of-life anxiety, addiction, OCD, eating disorders, cluster headaches, and more. Oregon legalized supervised psilocybin therapy in 2020, Colorado followed in 2022, and dozens of cities have decriminalized personal possession. From a safety standpoint, psilocybin mushrooms have one of the most favorable toxicity profiles of any psychoactive substance known to science. The therapeutic index is approximately 1,000:1 — comparable to vitamin C. No confirmed human fatalities from psilocybin toxicity alone exist in the scientific literature. The real risks are psychological, not physiological: difficult experiences, anxiety, and rare cases of persisting perceptual disturbances. With proper preparation, appropriate dosing, and attention to set and setting, these psychological risks can be very substantially mitigated.

2C-B (4-bromo-2,5-dimethoxyphenethylamine) is a synthetic psychedelic phenethylamine first synthesized by Alexander Shulgin in 1974 and documented as **compound #20** in his landmark 1991 book *PiHKAL: A Chemical Love Story*. Of the hundreds of novel psychoactive compounds Shulgin created, 2C-B is arguably the one that found the widest audience -- it is the most popular member of the 2C-x family worldwide and has remained a fixture in recreational and festival drug markets for over three decades [1]. What makes 2C-B distinctive is its dose-dependent personality. At lower doses (10--15 mg), it produces an empathogenic, sensory-rich experience with warm sociability and mild visual shimmer -- users often compare this range to a lighter, cleaner version of MDMA. At moderate to high doses (20--30 mg), it transitions into a fully psychedelic state with vivid, neon-saturated visuals, profound perceptual shifts, and an intensity that can rival LSD or psilocybin. This steep dose-response curve means a 5 mg difference can be the gap between a mellow social evening and a challenging psychedelic journey. Accurate dosing is not optional -- it is the single most important variable with 2C-B. Shulgin himself described 2C-B in 2003 as "one of the most graceful, erotic, sensual, introspective compounds I have ever invented" [2]. Community experience backs this up: Reddit users consistently praise 2C-B's visual beauty, its relatively light cognitive load compared to LSD, and the way it leaves you feeling functional and present rather than dissolved into abstract thought. Its shorter duration (4--6 hours oral) and generally smooth comedown make it one of the more manageable psychedelic experiences, which is part of why it became a staple for people who want vivid psychedelic visuals without the 10-hour commitment of acid. A 2023 double-blind clinical comparison of 2C-B (20 mg) versus psilocybin (15 mg) confirmed what the community has long reported: 2C-B produces genuine psychedelic alterations of consciousness, but with less dysphoria, less ego dissolution, and a shorter duration than psilocybin at these doses [3]. A persistent real-world concern is adulteration. Pills and powders sold as "2C-B" may contain NBOMe compounds, random novel phenethylamines, or mixtures marketed as "tucibi" or "pink cocaine" that often contain no actual 2C-B at all. The European Drug Report documented 944 seizures of 2C-B across 15 EU member states in 2023 alone, and the EUDA has specifically warned that "pink cocaine" products are unreliable and frequently misrepresented [4]. Reagent testing before use is essential -- not optional. ## References [1] Shulgin A, Shulgin A. PiHKAL: A Chemical Love Story. Transform Press. 1991. Compound #20. [2] Shulgin A. Quoted in Psychedelics.com. 2003. [3] Mallaroni P et al. Assessment of the Acute Effects of 2C-B vs. Psilocybin on Subjective Experience, Mood, and Cognition. Clin Pharmacol Ther. 2023;114(2):423-430. [4] European Drug Report 2024. European Union Drugs Agency (EUDA). Other drugs -- the current situation in Europe.

Lysergic acid diethylamide (LSD), universally known as acid, is a semisynthetic psychedelic of the lysergamide family and one of the most potent psychoactive substances ever discovered. Active at microgram doses — a typical hit contains 50-200 µg, roughly the weight of a few grains of salt — LSD produces sweeping alterations in perception, emotion, and cognition that last 8-12 hours. It was first synthesized in 1938 by Swiss chemist Albert Hofmann from ergotamine, an alkaloid of the ergot fungus (*Claviceps purpurea*), and its psychoactive properties were discovered accidentally five years later when Hofmann absorbed a trace amount through his skin. LSD works primarily by activating serotonin 5-HT2A receptors in the prefrontal cortex, disrupting the brain's predictive coding — the top-down filtering system that normally decides what sensory information reaches conscious awareness. The result is a perceptual floodgate opening: colors saturate and breathe, surfaces ripple with geometric patterns, music becomes architectural, and the ordinary world takes on an almost unbearable vividness. Cognitively, thoughts branch and accelerate, connections between distant ideas feel suddenly obvious, and at higher doses the sense of being a separate self can dissolve entirely — an experience called ego death that users describe as simultaneously the most terrifying and most meaningful thing they have ever lived through. The LSD experience is famously unpredictable. Set (your mindset going in) and setting (your physical environment) matter more than almost any other variable, including dose. The same tab that produces a transcendent afternoon in nature with a trusted friend can trigger hours of paranoid terror in a crowded, unfamiliar place. Community wisdom, backed by clinical research, is unanimous on this point: where you are and how you feel when you take it will shape the trip more than anything else. Culturally, LSD is inseparable from the 1960s counterculture, the psychedelic renaissance in psychiatric research, and an ongoing conversation about consciousness itself. After decades of prohibition following its Schedule I classification in 1970, clinical trials have resumed in earnest — MindMed's MM-120 received FDA Breakthrough Therapy designation in 2024 for generalized anxiety disorder, and multiple trials are exploring LSD-assisted therapy for depression and addiction. Despite its fearsome cultural reputation, LSD has an extraordinarily low physical toxicity profile — no confirmed human death from its pharmacological action alone has ever been documented.

N,N-Dimethyltryptamine (DMT) is a naturally occurring psychedelic tryptamine that holds a singular position in the world of psychoactive substances. It is found throughout the plant kingdom -- in grasses, bark, roots, and leaves across dozens of species -- and in trace amounts in mammalian tissue, including the human brain. A landmark 2019 study by Dean et al. confirmed that DMT is produced by neurons in the rat cerebral cortex at concentrations comparable to those of serotonin and dopamine, and that its levels spike dramatically during cardiac arrest. Whether endogenous DMT plays a functional role in human consciousness remains one of the most tantalizing open questions in neuroscience. When smoked or vaporized, DMT is among the most potent and rapid-onset psychedelic experiences known to humanity. Within 15 to 60 seconds of inhalation, a full dose catapults the user out of ordinary reality and into what is consistently described as a completely separate dimension -- a space populated by impossibly intricate geometric architecture, saturated color beyond the normal visual spectrum, and frequently, autonomous entities that appear aware, intelligent, and communicative. The entire experience resolves within 15 to 30 minutes, leaving the user back in their room with little residual impairment. People routinely describe it as the single most intense experience of their lives. Orally, DMT is inactive on its own because gut MAO-A enzymes destroy it before it reaches the brain. The Amazonian ceremonial brew ayahuasca solves this by combining DMT-containing plants (typically *Psychotria viridis*) with MAO-inhibiting plants (*Banisteriopsis caapi* vine), enabling oral activity and extending the duration to 4-6 hours. This tradition stretches back at least a millennium across hundreds of Indigenous groups, and has in recent decades spawned both a global spiritual tourism industry and serious clinical research into ayahuasca's potential for treating depression, addiction, PTSD, and existential distress. DMT's risks are primarily psychological and contextual, not physiological. No confirmed human fatality from DMT pharmacological action alone exists in the medical literature. The real dangers are: overwhelming psychological content without adequate preparation, physical vulnerability during the 10-20 minute incapacitation period, and -- critically for ayahuasca -- dangerous drug interactions between the MAOI component and serotonergic medications like SSRIs, which can trigger potentially fatal serotonin syndrome.

Cannabis is the single most widely used psychoactive substance on Earth outside of alcohol and caffeine, and arguably the one most poorly understood by the people debating it. Derived from the dried flowers of *Cannabis sativa*, *Cannabis indica*, and their countless hybrids, it has been cultivated by humans for at least 12,000 years -- longer than wheat, longer than rice, longer than almost any crop still grown today. People have smoked it, eaten it, brewed it into tea, pressed it into hashish, rubbed it on wounds, woven its fibers into rope, and offered it to gods. No other plant occupies such a strange position in human civilization: simultaneously sacred and criminal, medicine and menace, the subject of more research papers and more prison sentences than perhaps any other organism. The primary psychoactive compound in cannabis is delta-9-tetrahydrocannabinol (THC), a partial agonist at cannabinoid CB1 receptors throughout the brain. But reducing cannabis to "THC" is like reducing wine to "ethanol." The plant produces over 140 known cannabinoids, more than 200 terpenes, and a constellation of flavonoids that interact in ways researchers are still mapping. This complexity is why two strains with identical THC percentages can produce wildly different experiences -- one leaving you giggly and creative, the other bolting you to the couch in philosophical silence. The cannabis community calls this the "entourage effect," and while the science is still catching up, the lived experience of millions of users confirms that the whole plant is more than the sum of its parts. What makes cannabis pharmacologically fascinating is its target: the endocannabinoid system (ECS), a retrograde neuromodulatory network that your body runs regardless of whether you have ever touched cannabis. The ECS regulates pain, appetite, mood, memory, immune function, and reproductive processes. When you smoke a joint, THC essentially impersonates anandamide -- your brain's own endocannabinoid, named after the Sanskrit word for "bliss" -- and hijacks a system that evolution spent hundreds of millions of years building. This is why the cannabis high touches so many dimensions of experience simultaneously: hunger, time perception, music appreciation, anxiety, creativity, and bodily sensation all shift at once because they are all under endocannabinoid regulation. The contemporary cannabis landscape is one of radical transformation. As of 2026, recreational use is legal in over 24 US states, all of Canada, Germany, Uruguay, Thailand (with evolving regulations), and a growing list of nations. The US market alone exceeds $30 billion annually. Yet cannabis remains a Schedule I substance under US federal law, classified alongside heroin -- a contradiction that shapes everything from banking access to research funding. Meanwhile, approximately 30% of regular users meet criteria for cannabis use disorder, cannabis hyperemesis syndrome has received its own WHO diagnostic code, and the average THC content of commercial flower has roughly tripled since the 1990s. Cannabis is not the harmless herb some advocates claim, nor the societal destroyer prohibitionists warned of. It is a pharmacologically complex, deeply human substance that demands honest, nuanced understanding.