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25C-NBOMe

4-chloro-2,5-dimethoxy-N-(2-methoxybenzyl)phenethylamine

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25C-NBOMe — known as N-bomb or Smiles — is a synthetic psychedelic of the phenethylamine class. It is structurally derived from 2C-C with a single modification that increases potency by orders of magnitude.[1] It activates serotonin receptors in the brain,[2] disrupting sensory filtering and producing intense visual and perceptual changes.

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Threshold
< 50 µg
Light
100 – 300 µg
Common
300 – 700 µg
Strong
700 – 1000 µg
Heavy
1000+ µg
123450 h2 h4 h6 h8 h
1Onset
5m–15m2Come-up
15m–45m3Peak
3h–4h4Plateau
2h–3h5Resolution
1h–2hAftereffects4h–12h
Total8h–10h
Builduprapid
Full reset14 days
Cross-tol.
LSD, psilocybin, DMT +5 more
Absolute7 entries
cardiovascular diseaseepilepsypsychotic disordersbipolar disorderpregnancyconcurrent serotonergic medicationsconcurrent stimulant use
Dosage varies by body weight, tolerance & metabolism · Not medical advice · Terms

The NBOMe series was first synthesized in 2003 by Ralf Heim during doctoral research into high-affinity serotonin receptor compounds.[3] By 2010–2011, it reached drug markets routinely sold as LSD — a deception made possible because both are active at microgram doses and look identical on blotter.[4] It is now Schedule I in the United States and controlled in multiple jurisdictions worldwide.[5]

Subjective effects include geometric visual patterns, brightened colors, accelerated thinking, emotional intensification, and strong physical stimulation. The experience has a sharp, electric visual quality — more angular and saturated than tryptamine psychedelics, and more physically intense, with less cognitive depth. Blood vessel constriction, jaw tension, temperature dysregulation, and anxiety are common unwanted effects.

25C-NBOMe produces no physical dependence,[6] but its acute toxicity is severe — fatal outcomes have been documented at recreational doses.[7] The dose-response curve is steep and poorly characterized, and combining it with stimulants or serotonergic drugs dramatically amplifies the risk of life-threatening toxicity. No controlled human studies exist; the evidence base rests entirely on fatal case reports and retrospective user accounts.

History[edit]

Discovery

The NBOMe structural modification was introduced by Ralf Heim in a 2003 doctoral dissertation, where he showed that adding an N-(2-methoxybenzyl) group to 2C-series compounds increased serotonin receptor binding by orders of magnitude.[3] A Copenhagen neuroimaging group later developed these compounds as brain imaging tools, assigning 25C-NBOMe the research designation Cimbi-82.[5]

Entry into drug markets

NBOMe compounds appeared on online drug markets between 2010 and 2011.[1][8] They were routinely sold as LSD — both are active at microgram doses and can be applied to blotter paper, making them visually indistinguishable.[4] As recently as 2024, a public drug warning was issued in Australia after 25C-NBOMe was found in samples sold as 2C-B.citation needed

Regulatory response

The U.S. Drug Enforcement Administration placed 25C-NBOMe into Schedule I on November 15, 2013,[5] with the order extended in 2015.[9] The United Kingdom classified all NBOMe compounds as Class A substances in June 2014.[10] Multiple additional jurisdictions enacted controls in the following years, driven by documented fatalities and emergency presentations.

Chemistry[edit]

25C-NBOMe belongs to the NBOMe subclass of substituted phenethylamines.[1] Its parent compound is 2C-C, a member of the 2C-X series first synthesized by Alexander Shulgin; adding the N-(2-methoxybenzyl) group to the parent dramatically increases serotonin receptor binding affinity.[2][1]

The "25C" prefix identifies the chlorine atom at the 4-position of the ring, distinguishing it from the iodo and bromo variants of the series, which tend to be more potent.[12] Its molecular formula is C₁₈H₂₂ClNO₃ (molecular weight 335.8 g/mol), and the molecule contains no chirality centers.

Pharmacology[edit]

Mechanism of action

25C-NBOMe is a potent agonist at serotonin receptors.[1][2] Activating these receptors disrupts the brain's normal sensory filtering, producing the psychedelic state.[13] Despite its high binding strength, it behaves as a partial agonist — it activates the receptor less fully than its affinity alone would predict.[2]

Pharmacokinetics

Routes of administration

The primary route is sublingual or buccal — typically by holding blotter paper under the tongue.[1][4] Intranasal use produces a faster, more intense onset. Sublingual administration is preferred over oral ingestion, likely because it bypasses the liver's first processing of the drug.

Metabolism and detection

No controlled human pharmacokinetic data have been published for 25C-NBOMe. The primary breakdown pathway removes methoxy groups, followed by further modification and conjugation before excretion.[7][14][15][16] The compound does not appear on standard drug screens — detection requires specialized mass spectrometry.[17][4]

Neuroscience[edit]

Where it acts

No direct brain imaging or electrophysiology studies have been published for 25C-NBOMe. Based on its serotonin receptor activity, it is expected to trigger glutamate release in the prefrontal cortex — disrupting the brain's normal filtering of sensory input and producing the characteristic state of heightened perception and altered thinking.[13] Its partial agonist character[2] may reduce the magnitude of these effects compared to full agonists, though this has not been tested.

Why it matters

One framework proposes that psychedelics reduce the brain's confidence in its own predictions, letting raw sensory input dominate — consistent with the effects expected from 25C-NBOMe's receptor activity. Tolerance develops through downregulation: repeated activation causes the brain to reduce the number of available serotonin receptors, directly explaining why psychedelic effects diminish with repeated use.[18]

Subjective Effects[edit]

Summary

The 25C-NBOMe experience is dominated by visual intensity — a sharp, electric quality that users describe as angular and saturated rather than the organic, flowing geometry of tryptamine psychedelics. Physical stimulation is a defining feature, running throughout the experience and coloring the entire state.

Compared to LSD, the experience carries heavier body effects and a narrower subjective quality — more sensory intensity, less cognitive depth. Compared to its parent compound 2C-C, the NBOMe modification produces a dramatically more intense stimulant component alongside the visual effects.

Effect Grid

Dose Level:
Description

At common doses (300–700 µg sublingual), the full psychedelic experience manifests. Pronounced open-eye visuals include geometric patterning overlaid on surfaces, color shifting and saturation, environmental drifting and morphing, and tracers behind moving objects. Closed-eye visuals feature complex geometry and vivid imagery. Time distortion becomes significant. Thought connectivity increases dramatically, producing novel associations; thought loops and conceptual confusion may occur. Emotional intensification is pronounced — music, nature, and social interactions can feel profoundly meaningful or overwhelming depending on set and setting.

Physically, stimulation is prominent. Jaw tension, body load, vasoconstriction (cold hands and feet), temperature dysregulation, and difficulty urinating are common. Nausea and muscle tension occur in a subset of users.

This is a significant commitment: the experience lasts 8–10 hours with residual effects persisting beyond. Sleep is impossible for at least 8 hours. The steep dose-response curve means small increases within this range can produce disproportionately stronger effects.

Modeled from the effect's dose-dependence curve — not per-substance measurements.

Perception(51)likelihood · intensity
Color enhancement
likely
Visual drifting
likely
Color alteration
likely
Geometry
likely
Tracers
likely
Music enhancement
likely
Brightness alteration
likely
Environmental patterning
likely
Double vision!
possible

Tracers · Music enhancement · Brightness alteration · Environmental patterning · Light sensitivity · Peripheral vision distortion · Perspective distortion · Visual breathing · Visual morphing · Symmetrical texture repetition · Auditory distortion · Auditory enhancement · Depth perception distortion · Sound sensitivity · Visual melting · Visual diffraction · Vestibular distortion · After-images · Peripheral misidentification · Spatial disorientation · Touch enhancement · Visual haze / noise · Synesthesia · Visual acuity enhancement · Auditory misinterpretation · Holotropic state · Proprioceptive distortion · Visual processing acceleration · Visual magnification · Olfactory enhancement · Taste enhancement · Touch suppression · Flashbacks · Object transformations · Internal hallucinations · External hallucinations · Visual recursion · Environmental orbism / cubism · Object activation · Visual scenery slicing · Auditory hallucinations · Visual flipping · Perspective hallucinations · Shadow people · Gustatory hallucination · Persisting hallucinations

Light sensitivity · Peripheral vision distortion · Perspective distortion · Visual breathing · Visual morphing · Symmetrical texture repetition · Auditory distortion · Auditory enhancement · Depth perception distortion · Sound sensitivity · Visual melting · Visual diffraction · Vestibular distortion · After-images · Peripheral misidentification · Spatial disorientation · Touch enhancement · Visual haze / noise · Synesthesia · Visual acuity enhancement · Auditory misinterpretation · Holotropic state · Proprioceptive distortion · Visual processing acceleration · Visual magnification · Olfactory enhancement · Taste enhancement · Touch suppression · Flashbacks · Object transformations · Internal hallucinations · External hallucinations · Visual recursion · Environmental orbism / cubism · Object activation · Visual scenery slicing · Auditory hallucinations · Visual flipping · Perspective hallucinations · Shadow people · Gustatory hallucination · Persisting hallucinations

Body(42)likelihood · intensity
Wakefulness
likely
Stimulation
likely
Vasoconstriction!
likely
Pupil dilation
likely
Body scan awareness
likely
Muscle tension
likely
Appetite suppression
likely
Motor control impairment!
possible
Temperature dysregulation!
possible

Body scan awareness · Muscle tension · Appetite suppression · Dry mouth · Body high · Heart rate perception changes · Spontaneous body sensations · Restlessness · Excessive sweating · Insomnia · Physical fatigue · Tingling / electric sensations · Vibrations / buzzing · Nausea · Dehydration sensation · Headache · Bruxism · Dizziness · Tactile euphoria · Temperature dysregulation · Bodily lightness · Abnormal heartbeat · Bodily pressures · Body schema distortion · Laughter fits · Nystagmus (eye wobbles) · Sexual arousal enhancement · Seizure threshold reduction · Breathing alteration · Involuntary body movements · Respiratory stimulation · Trembling · Increased urination · Pain enhancement · Vomiting · Tactile hallucination · Bodily dissociation

Dry mouth · Body high · Heart rate perception changes · Spontaneous body sensations · Restlessness · Excessive sweating · Insomnia · Physical fatigue · Tingling / electric sensations · Vibrations / buzzing · Nausea · Dehydration sensation · Headache · Bruxism · Dizziness · Tactile euphoria · Bodily lightness · Abnormal heartbeat · Bodily pressures · Body schema distortion · Laughter fits · Nystagmus (eye wobbles) · Sexual arousal enhancement · Seizure threshold reduction · Breathing alteration · Involuntary body movements · Respiratory stimulation · Trembling · Increased urination · Pain enhancement · Vomiting · Tactile hallucination · Bodily dissociation

Thinking(37)likelihood · intensity
Novelty enhancement
likely
Immersion enhancement
likely
Pattern recognition enhancement
likely
Aesthetic enhancement
likely
Thought acceleration
possible
Conceptual thinking
possible
Decision impairment!
possible
Suggestibility enhancement!
possible
Compulsive redosing urge!
possible

Aesthetic enhancement · Thought acceleration · Conceptual thinking · Introspection enhancement · Multiple thought streams · Openness enhancement · Thought connectivity · Memory suppression · Cognitive euphoria · Cognitive flexibility · Cognitive impairment · Thought loops · Creativity enhancement · Humor enhancement · Cognitive dysphoria · Cognitive fatigue · Confusion · Focus suppression · Information processing suppression · Memory fragmentation · Synchronicity · Thought disorganization · Analysis enhancement · Language suppression · Analysis suppression · Compulsive redosing urge · Focus enhancement · Information processing enhancement · Delusions of sobriety · Amnesia · Delirium · Delusions

Introspection enhancement · Multiple thought streams · Openness enhancement · Thought connectivity · Memory suppression · Cognitive euphoria · Cognitive flexibility · Cognitive impairment · Thought loops · Creativity enhancement · Humor enhancement · Cognitive dysphoria · Cognitive fatigue · Confusion · Focus suppression · Information processing suppression · Memory fragmentation · Synchronicity · Thought disorganization · Analysis enhancement · Language suppression · Analysis suppression · Focus enhancement · Information processing enhancement · Delusions of sobriety · Amnesia · Delirium · Delusions

Feeling(12)likelihood · intensity
Emotional enhancement
likely
Emotional lability
possible
Euphoria
possible
Anxiety
possible
Simultaneous emotions
possible
Empathy enhancement
possible
Paranoia!
possible
Depression!
rare
Mania!
rare

Anxiety · Simultaneous emotions · Empathy enhancement · Dysphoria · Catharsis · Irritability · Mania

Dysphoria · Catharsis · Irritability

Self(20)likelihood · intensity
Emotional susceptibility
possible
Derealization
possible
Depersonalization
possible
Disinhibition
possible
Social connection
possible
Sociability enhancement
possible
Communication suppression
possible
Compulsive repetitive behavior!
rare
Self-control suppression!
rare

Disinhibition · Social connection · Sociability enhancement · Communication suppression · Social disconnection · Trust enhancement · Communication enhancement · Flow state · Ego inflation · Sociability suppression · Boundary dissolution · Cognitive disconnection · Identity alteration · Ego dissolution · Telepathic feelings

Social disconnection · Trust enhancement · Communication enhancement · Flow state · Ego inflation · Sociability suppression · Boundary dissolution · Cognitive disconnection · Identity alteration · Ego dissolution · Telepathic feelings

Time(5)likelihood · intensity
Time alteration
likely
Temporal disorientation
possible
Present-moment absorption
possible
Deja vu
rare
Time cessation
v.rare
Transpersonal(8)likelihood · intensity
Unity and interconnectedness
possible
Existential realization
rare
Noetic insight
v.rare
Transpersonal feelings
v.rare
Transpersonal visions
v.rare
Entity contact
v.rare
Non-dual awareness
v.rare
Near-death experience
v.rare

Entity contact · Non-dual awareness · Near-death experience

Awareness(4)likelihood · intensity
Personal insight
possible
Cognitive dissonance
possible
Reality testing impairment!
rare
Recursive awareness
rare
Likelihood: how common this effect is at the selected dose level.This effect has safety implications — review before use.

Timeline

Safety[edit]

Harm
Acute toxicity
Critical
Chronic toxicity
Moderate
Withdrawal
None
Tolerance buildup
rapid
Tolerance reset
14 days
Dependence
Physical
None
Psychological
Low
Compulsive redosing
Negligible
Dose escalation
Negligible
Cross-tol.
LSD · psilo · DMT
Risk Shape
TOXPHYPSYWDRREDTOL

Toxicity

Acute toxicity

25C-NBOMe has a critical acute toxicity profile. The margin between common recreational doses (300–700 µg sublingual) and doses associated with fatal outcomes is unknown and presumed narrow.[7] The first confirmed fatal poisoning involved a young man who died approximately 12 hours after ingestion, with preceding signs of severe serotonin-related toxicity.[7]

25C-NBOMe has a steep and poorly characterized dose-response curve. Fatal outcomes have been documented at recreational doses. The dose values listed in this article are derived from user reports, not controlled studies, and do not establish a safe dose ceiling.

Toxicity features

The NBOMe class produces a recognizable pattern of severe toxicity[1][19][20]:

Severe agitation and seizures have been reported lasting up to three days.[4]

Management of acute toxicity

Based on published case series[19][1]:

  • Benzodiazepines are the first-line treatment for agitation and seizures; high doses may be required
  • Active cooling is critical — elevated body temperature drives muscle breakdown and kidney failure
  • Supportive care targeting presenting symptoms; no specific antidote exists
  • Standard drug screens do not detect NBOMe compounds — confirmatory laboratory testing is required[17][4]

Psychological risks

Severe psychological distress — including panic, paranoia, and psychotic episodes — is documented across the NBOMe class.[1][20] Prolonged psychotic episodes and excited delirium lasting days have been reported.[4] Persistent visual disturbances following use — patterns or colors that linger long after the experience ends — are a risk consistent with serotonergic psychedelics generally.citation needed

The steep dose-response curve, frequent misrepresentation as LSD, and variable blotter dosing mean users may unknowingly take far more than expected — compounding psychological risk.

Tolerance and dependence

Tolerance develops quickly through downregulation: the brain reduces the number of available serotonin receptors in response to repeated activation.[18] User reports estimate tolerance half-life at approximately 7 days, with full reset at 14 days.[22]

Full cross-tolerance exists with all serotonin-agonist psychedelics, including LSD, psilocybin, DMT, mescaline, and all other NBOMe compounds.[18] No physical dependence or withdrawal has been documented.[6]

Drug interactions

Serotonergic drugs are the most dangerous interaction class. Taking 25C-NBOMe alongside SSRIs, SNRIs, MAOIs, or tramadol can trigger serotonin syndrome — a potentially life-threatening overheating, muscle spasm, and seizure response. Tramadol poses a double risk: it raises serotonin and lowers the seizure threshold, both of which are already features of NBOMe toxicity.[1]inferred

Stimulants like cocaine or amphetamines add cardiovascular strain on top of 25C-NBOMe's vasoconstriction, creating compounded risk of severe blood pressure elevation, irregular heartbeat, and stroke.[1]inferred The confirmed fatal case involved co-ingestion of amphetamine.[7]

MDMA adds serotonergic burden and elevated body temperature risk. Cannabis may unpredictably intensify psychedelic effects and anxiety. Polydrug use involving NBOMes with serotonergic substances increases the risk of severe adverse outcomes.[6]

Contraindications

No substance-specific contraindication studies exist. The following are inferred from 25C-NBOMe's pharmacological and toxicological profile:

  • Heart conditions — severe blood vessel constriction and blood pressure elevation create direct cardiovascular danger
  • Seizure disorders — NBOMe compounds lower seizure threshold; seizures are a documented feature of acute toxicity[1]
  • Serotonergic medications — SSRIs, SNRIs, MAOIs, tramadol: risk of serotonin syndrome
  • Concurrent stimulant use — cocaine, amphetamines: additive cardiovascular toxicity
  • Personal or family history of psychotic disorders — serotonin receptor activation may precipitate or worsen psychosis
  • Pregnancy — no safety data exist; effects on fetal development are unknownsafety citation needed

Harm Reduction[edit]

Forms & Identification

Reagent ResultsNot recorded+ add reagent results
AppearanceNot recorded+ add appearance
Red FlagsNot recorded+ add red flags

The primary risk with 25C-NBOMe is unknowing exposure: it is routinely sold as LSD on blotter paper, and the two are visually indistinguishable.[4] A bitter, numbing taste on the tongue strongly suggests an NBOMe compound — LSD is tasteless. Reagent testing helps but cannot definitively confirm identity; drug checking services using mass spectrometry provide the most reliable confirmation.

Guidelines

  • Test every sample before use — reagent kits provide preliminary identification, but professional drug checking services are strongly recommended for NBOMe-class compounds
  • Start with the lowest reported active dose and wait at least 90 minutes before considering redosing — the dose-response curve is steep and unpredictable
  • Never use alone; a sober, informed sitter should be present throughout
  • Ensure the environment is temperature-controlled — elevated body temperature is a hallmark of NBOMe toxicity
  • Stay hydrated but avoid excessive water intake
  • Have benzodiazepines available for managing anxiety or agitation if accessible

Set & Setting

Set and setting exert an outsized influence on the 25C-NBOMe experience. Pronounced stimulation and a steep dose-response curve mean anxiety or uncomfortable environments can rapidly escalate into distressing psychological states. A calm, familiar space with temperature control, water access, and a trusted sober companion substantially reduces the risk of panic and dangerous behavior.

Aftercare & integration. The stimulant load and long duration of 25C-NBOMe can leave users physically exhausted. Prioritize sleep, hydration, and light nutrition in the 24 hours following use. Physical discomfort — jaw tension, headache, residual vasoconstriction — may persist into the following day.

Psychologically intense experiences benefit from deliberate processing: writing about the experience, discussing it with a trusted person, or seeking professional support if distressing effects persist beyond 48 hours. Persistent visual disturbances, anxiety, or depersonalization warrant professional consultation.

Recovery & Support

While 25C-NBOMe does not produce physical dependence, repeated use despite negative consequences — particularly among individuals using it unknowingly as LSD — may indicate a broader pattern of substance misuse. Community harm reduction organizations, psychedelic peer support services, and mental health professionals experienced with substance-related issues can provide support. The Fireside Project (62-FIRESIDE / 623-473-7433) offers free psychedelic peer support.

Recovery resources, crisis lines, and support pathways → View all

Emergency Response

Recognizing an emergency: Seek immediate medical help if any of the following occur: seizures, loss of consciousness, chest pain, body temperature hot to the touch, uncontrollable agitation or violent behavior, confusion lasting more than several hours, or difficulty breathing.

Immediate steps:

  • 1. Call emergency services immediately — do not wait to see if symptoms improve
  • 2. Move the person to a cool environment and apply cold compresses to neck, armpits, and groin
  • 3. If unconscious but breathing, place them in the recovery position (on their side)
  • 4. Do not restrain them unless they are in immediate danger of harming themselves
  • 5. Do not induce vomiting

What to tell the dispatcher: Name the substance (25C-NBOMe or "an NBOMe compound"), approximate amount and time of ingestion, current symptoms, and any other substances taken. Good Samaritan laws in many jurisdictions protect people who call for help during a drug emergency.

No reversal agent exists for NBOMe toxicity. Treatment is supportive — benzodiazepines for agitation and seizures, active cooling for elevated body temperature.

references

  1. [1] 
    ^abcdefghijklmZawilska JB, Kacela M, Adamowicz P (2020) NBOMes-Highly Potent and Toxic Alternatives of LSD — Frontiers in Neuroscience doi:10.3389/fnins.2020.00078
  2. [2] 
    ^abcdeElmore JS, Decker AM, Sulima A, Rice KC, Partilla JS, Blough BE, Baumann MH (2018) Comparative neuropharmacology of N-(2-methoxybenzyl)-2,5-dimethoxyphenethylamine (NBOMe) hallucinogens and their 2C counterparts in male rats — Neuropharmacology doi:10.1016/j.neuropharm.2018.02.033
  3. [3] 
    ^abHeim (2003) Synthese und Pharmakologie potenter 5-HT2A-Rezeptoragonisten mit N-2-Methoxybenzyl-Partialstruktur [Synthesis and pharmacology of potent 5-HT2A receptor agonists with N-2-methoxybenzyl partial structure]
  4. [4] 
    ^abcdefghPoklis JL, Raso SA, Alford KN, Poklis A, Peace MR (2015) Analysis of 25I-NBOMe, 25B-NBOMe, 25C-NBOMe and Other Dimethoxyphenyl-N-[(2-Methoxyphenyl)Methyl]Ethanamine Derivatives on Blotter Paper. — Journal of Analytical Toxicology doi:10.1093/jat/bkv073
  5. [5] 
    ^abcdDrug Enforcement Administration (2013) Schedules of controlled substances: temporary placement of three synthetic phenethylamines into Schedule I. Final order. — Federal Register PMID:24236337
  6. [6] 
    ^abcLuethi D, Liechti ME (2020) Designer drugs: mechanism of action and adverse effects — Archives of Toxicology doi:10.1007/s00204-020-02693-7