Ketamine, MDMA, and ibogaine are routinely lumped in with psychedelics, but pharmacologically they are different animals — and that difference is the whole point of this page. Ketamine is a dissociative that blocks the NMDA glutamate receptor; [1] Peer-reviewed Mechanisms of ketamine action as an antidepressant doi:10.1038/mp.2017.255 MDMA mainly releases serotonin, dopamine, and noradrenaline rather than acting as a 5-HT2A agonist; [2] Peer-reviewed Dark Classics in Chemical Neuroscience: 3,4-Methylenedioxymethamphetamine doi:10.1021/acschemneuro.8b00155 ibogaine has a complex multi-receptor profile and a serious cardiac risk. None is a classic serotonergic psychedelic, [3] Peer-reviewed Psychedelics doi:10.1124/pr.115.011478 so microdosing claims built on psilocybin or LSD do not transfer to them. Their clinical research, where it exists, uses full or specific therapeutic doses under supervision — not sub-perceptual microdosing — and MDMA carries distinct neurotoxicity and cardiac-valve concerns with repeated exposure. [4] analysis The risk of chronic psychedelic and MDMA microdosing for valvular heart disease doi:10.1177/02698811231190865
This is an education-only research review, not sourcing, dosing, medical, or legal advice. It describes what these substances are and why they differ from classic psychedelics. It does not recommend, dose, or advise the use of any of them, and ketamine in particular is a prescription medicine whose clinical use is directed by clinicians. For personal decisions, consult a qualified clinician.
Ketamine: a dissociative, not a psychedelic
Ketamine is a dissociative anaesthetic. Its principal mechanism is antagonism of the NMDA glutamate receptor, with downstream effects on glutamate signalling that are the focus of its antidepressant research — a pathway entirely distinct from the 5-HT2A agonism that defines classic psychedelics. [1] Peer-reviewed Mechanisms of ketamine action as an antidepressant doi:10.1038/mp.2017.255 [3] Peer-reviewed Psychedelics doi:10.1124/pr.115.011478 The antidepressant literature uses specific sub-anaesthetic doses delivered in clinical settings, and a derivative, esketamine, is an approved prescription product. That is full therapeutic dosing under medical supervision, not microdosing, and it does not license low-dose self-use by analogy to psilocybin.
MDMA: release, not agonism
MDMA is a phenethylamine, but it does not act like the classic psychedelics. Instead of agonising 5-HT2A as its primary action, it triggers large release of serotonin and, to varying degrees, dopamine and noradrenaline, producing a subjective profile unlike either stimulants or hallucinogens. [2] Peer-reviewed Dark Classics in Chemical Neuroscience: 3,4-Methylenedioxymethamphetamine doi:10.1021/acschemneuro.8b00155 Its clinical research targets full-dose, therapist-supported sessions for trauma — again, not microdosing. Two features make it a poor fit for frequent low dosing: the large serotonin release raises neurotoxicity concerns with repeated use, and, like other chronic serotonergic agents, it has been examined for 5-HT2B-mediated cardiac valve risk with sustained exposure. [4] analysis The risk of chronic psychedelic and MDMA microdosing for valvular heart disease doi:10.1177/02698811231190865
Ibogaine: complex pharmacology, serious cardiac risk
Ibogaine has a complicated multi-receptor pharmacology and an extremely long duration. It is studied at full doses in addiction-interruption contexts, not microdosed, and it carries a well-documented cardiac risk: it can prolong the QT interval and has been associated with dangerous arrhythmias, so medical screening is emphasised wherever it is used or studied. It should be treated as a high-risk adjacent substance because of these cardiac-toxicity concerns and serious adverse-event reports, and it should not be folded into ordinary microdosing discussion at all. It is included here to be identified and bounded, not to be encouraged; the cardiac concern is treated in the safety cluster.
| Substance | Primary mechanism | Class | Microdosing status |
|---|---|---|---|
| Ketamine | NMDA receptor antagonist | Dissociative | Clinical sub-anaesthetic dosing, not microdosing |
| MDMA | Serotonin/dopamine/noradrenaline release | Empathogen (phenethylamine) | Full-dose therapy research; poor low-dose fit |
| Ibogaine | Complex multi-receptor | Iboga alkaloid | Full-dose only; serious cardiac risk |
| Classic psychedelics | 5-HT2A agonism | Serotonergic psychedelic | The only group with microdosing evidence |
Why the claims do not transfer
The error this page guards against is reasoning from “psychedelic-assisted therapy shows promise” to “therefore I can microdose ketamine or MDMA like mushrooms.” The premise and the conclusion involve different drugs, different mechanisms, different doses, and different supervision. Pharmacological category matters: a benefit observed for a 5-HT2A agonist at one dose, in one setting, says nothing about a glutamate antagonist or a serotonin releaser at another. And plausibility is not demonstrated efficacy: that these drugs affect mood-relevant systems does not establish that microdosing them does anything.
| Substance | Why it is adjacent | Why microdosing claims do not transfer |
|---|---|---|
| Ketamine | Psychoactive dissociative used in psychiatric settings | NMDA-related mechanism, not classic 5-HT2A psychedelic microdosing |
| MDMA | Entactogen often discussed alongside psychedelics | Monoamine release, different risk and neurotoxicity profile |
| Ibogaine | Complex psychoactive used in addiction interruption | Complex pharmacology and serious cardiac risk; full-dose only |
For mechanisms, see the pharmacology overview; for drug-combination risk, the interactions overview; for what the low-dose evidence actually covers, what the research covers; and for the novel compounds that push uncertainty further, novel and research chemicals.
- Ketamine = NMDA antagonist
- A dissociative working on glutamate, not a 5-HT2A agonist; its dosing is clinical, not micro. [1] Peer-reviewed Mechanisms of ketamine action as an antidepressant doi:10.1038/mp.2017.255
- MDMA = releaser
- It releases monoamines rather than agonising 5-HT2A, with distinct neurotoxicity concerns. [2] Peer-reviewed Dark Classics in Chemical Neuroscience: 3,4-Methylenedioxymethamphetamine doi:10.1021/acschemneuro.8b00155
- Ibogaine = cardiac caution
- Complex pharmacology and QT-prolongation risk; full-dose only, never a microdosing candidate.
- Claims don't transfer
- Findings for classic psychedelics do not carry over to drugs with other mechanisms.
Frequently asked questions
Are ketamine and MDMA psychedelics?
Not in the pharmacological sense used for the classic psychedelics. Ketamine is a dissociative anaesthetic that works mainly by blocking the NMDA glutamate receptor; [1] Peer-reviewed Mechanisms of ketamine action as an antidepressant doi:10.1038/mp.2017.255 MDMA primarily triggers release of serotonin, dopamine, and noradrenaline rather than acting as a 5-HT2A agonist. [2] Peer-reviewed Dark Classics in Chemical Neuroscience: 3,4-Methylenedioxymethamphetamine doi:10.1021/acschemneuro.8b00155 In everyday speech both get called psychedelics, but they belong to different pharmacological categories with different effects, risks, and clinical contexts. Grouping them with psilocybin and LSD is a common error this page exists to correct.
If they treat depression, can I microdose them like psilocybin?
No — that inference does not hold. Ketamine’s antidepressant research uses specific sub-anaesthetic doses delivered clinically, and esketamine is an approved prescription product; this is full therapeutic dosing under supervision, not sub-perceptual microdosing, and the mechanism is different from classic psychedelics. [1] Peer-reviewed Mechanisms of ketamine action as an antidepressant doi:10.1038/mp.2017.255 MDMA’s clinical research targets full-dose, therapist-supported sessions for trauma, not microdosing, and frequent low dosing raises distinct neurotoxicity concerns. [2] Peer-reviewed Dark Classics in Chemical Neuroscience: 3,4-Methylenedioxymethamphetamine doi:10.1021/acschemneuro.8b00155 Microdosing claims built on psilocybin or LSD do not transfer to drugs that work through other systems.
Why is ibogaine treated as separate and high-caution?
Ibogaine has a complex, multi-receptor pharmacology and an extremely long duration, and it carries a serious cardiac risk signal — it can prolong the QT interval and has been associated with dangerous arrhythmias, which is why medical screening is emphasised wherever it is studied. It is used at full doses in addiction-interruption contexts, not microdosed. This page notes what it is and why it sits outside any microdosing framework; it is not guidance to use it, and the cardiac concern is covered in the safety cluster.
Does MDMA carry risks that classic psychedelics do not?
Yes, distinct ones. Because MDMA causes large serotonin release and has metabolites and pharmacology different from 5-HT2A agonists, frequent use raises neurotoxicity concerns not associated with classic psychedelics in the same way, [2] Peer-reviewed Dark Classics in Chemical Neuroscience: 3,4-Methylenedioxymethamphetamine doi:10.1021/acschemneuro.8b00155 and like other serotonergic agents it has been discussed in the context of 5-HT2B receptor activation and cardiac valve risk with chronic exposure. [4] analysis The risk of chronic psychedelic and MDMA microdosing for valvular heart disease doi:10.1177/02698811231190865 These are reasons it is poorly suited to frequent low dosing. The detail belongs to the safety and interactions clusters; here it is part of explaining why MDMA is pharmacologically not a classic psychedelic.
Is MDMA microdosing the same kind of practice as psilocybin microdosing?
No. MDMA has different pharmacology — it primarily releases serotonin, dopamine, and noradrenaline rather than agonising 5-HT2A [2] Peer-reviewed Dark Classics in Chemical Neuroscience: 3,4-Methylenedioxymethamphetamine doi:10.1021/acschemneuro.8b00155 — along with different risk concerns and a different evidence base. Claims about psilocybin or LSD microdosing should not be transferred to MDMA, and its clinical research uses full, therapist-supported doses for trauma rather than sub-perceptual repeated dosing. Treating low-dose MDMA as the same practice as psilocybin microdosing collapses two pharmacologically distinct things.