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25B-NBOH Facts

Psychedelic; Substituted phenethylamine; Serotonin 2A receptor agonist

Description

25B-NBOH (2C-B-NBOH) is a synthetic psychedelic of the phenethylamine class. It activates serotonin receptors in the brain, producing the visual distortions and altered perception characteristic of classical psychedelics.

Subjective effects include geometric visual patterns, brightened colors, emotional intensification, racing heart, elevated blood pressure, and dilated pupils. The experience carries a heavier physical edge than classical psychedelics — the body is conspicuously activated throughout.[1]

25B-NBOH does not produce physical dependence,[2] but cardiovascular toxicity is a real acute risk — structural analogs inhibit cardiac ion channels,[3] and deaths are documented across the NBOMe/NBOH class.[4][5] Combining it with monoamine oxidase inhibitors — which prevent serotonin breakdown — is especially dangerous.

Dose and durationby route · individual sensitivity varies

Sublingual(µg)
Threshold< 100 µgLight200 – 400 µgCommon400 – 800 µgStrong800 – 1000 µgHeavy1000+ µg

Starts in 15 – 45 minLasts 4 – 6 hoursAfter-effects 2 – 6 hours

Body and dependence

Acute toxicity
High
Chronic toxicity
Moderate
Physical dependence
None
Psychological dependence
Negligible
Withdrawal
None recorded
Compulsive redosing
Negligible

Tolerance

Builds
Rapid
Fully resets after
14 days
Carries over to
LSD; psilocybin; DMT; DOx compounds; mescaline; other serotonergic psychedelics

Effectslikely at a common dose

Perception
Color enhancement; Visual drifting; Color alteration; Music enhancement; Geometry; Visual breathing; +26 possible, including Spatial disorientation, Visual haze / noise, Vestibular distortion
Body
Stimulation; Pupil dilation; Wakefulness; Body high; +26 possible, including Temperature dysregulation, Muscle tension, Vasoconstriction
Thinking
Aesthetic enhancement; +25 possible, including Cognitive impairment, Decision impairment, Suggestibility enhancement
Feeling
Emotional enhancement; +7 possible, including Emotional lability, Anxiety, Paranoia
Self
none likely · 8 possible, including Derealization, Depersonalization
Time
Time alteration; +2 possible, including Temporal disorientation
Transpersonal
none likely · 1 possible
Awareness
none likely · 2 possible

Who shouldn't take it

Absolute
Pre-existing cardiac disease or Long QT syndrome; Epilepsy or reduced seizure threshold; Pregnancy or lactation; Concurrent MAO inhibitor therapy; Concurrent tramadol use; Concurrent lithium therapy
Relative
Psychotic disorders

Combinations61 recorded

Lethal (1)
MAOIs
Dangerous (18)
MDMA, MDA; NRIs; Buspirone; Dopamine agonists; GHB, Baclofen; GHB, GBL; Ibogaine; Ketamine, DXM, PCP; Lithium; Local anesthetics; MDMA, Amphetamines; NDRIs (Wellbutrin); Psychedelics; Salvia, Ibogaine; SNRIs; SSRIs; Stimulants; Synthetic cannabinoids
Caution (37)
See full page: psychedex.org/substances/25b-nboh
Not graded (5)
Not listed never means safe.

Seek help immediately if

Most difficulty is psychological (intense fear, panic, confusion) and passes with calm support — the signs below mean seek emergency help:

  • Very high body temperature; hot, dry skin
  • Seizures
  • Chest pain; fast or irregular heartbeat
  • Severe muscle rigidity, tremor, or twitching (possible serotonin syndrome)
  • Cold, pale, or blue fingers/toes — severe vasoconstriction (notably NBOMe / DOx)
  • Persistent vomiting; unconsciousness; uncontrollable agitation or risk of self-harm

What to do

  1. Stay calm and reassure — remind them they took a drug and the effect will pass
  2. Move to a calm, quiet, safe space with low light; reduce noise and sensory input
  3. Keep them from harm — they may act on fear or confusion; stay with them, don't leave them alone
  4. Talk them down gently; don't grab or restrain unless they're in danger
  5. For the medical signs above (overheating, seizure, chest pain, vasoconstriction, unresponsive) call emergency services
  6. If overheating, cool the body; be ready to give rescue breaths / CPR

The experience is time-limited and usually resolves with calm reassurance in a safe setting — psychological first aid, not medication. Serious physical harm is uncommon for classic psychedelics (LSD, psilocybin) but real for some potent phenethylamines (NBOMe, DOx), where hyperthermia, seizures, and vasoconstriction warrant emergency care.

988 Suicide & Crisis LifelineFireside Project: 62-FIRESIDE

Version r1 · Not medical advice

References

  1. [1]
    ^Ivory ST, Rotella JA, Schumann J, Greene SL (2022) A cluster of 25B-NBOH poisonings following exposure to powder sold as lysergic acid diethylamide (LSD) — Clinical Toxicology doi:10.1080/15563650.2022.2053150
  2. [2]
    ^Eshleman AJ, Wolfrum KM, Reed JF, Kim SO, Johnson RA, Janowsky A (2018) Neurochemical pharmacology of psychoactive substituted N-benzylphenethylamines: High potency agonists at 5-HT2A receptors. — Biochemical Pharmacology doi:10.1016/j.bcp.2018.09.024
  3. [3]
    ^Yoon KS, Cha HJ, Choi SO, Lee JM (2022) 2-((2-(4-Iodo-2,5-dimethoxyphenyl)ethylamino)methyl)phenol (25I-NBOH) and 2-(((2-(4-chloro-2,5-dimethoxyphenyl)ethyl)amino)methyl)phenol (25C-NBOH) induce adverse effects on the cardiovascular system — Toxicology Letters doi:10.1016/j.toxlet.2021.11.016
  4. [4]
    ^Zawilska JB, Kacela M, Adamowicz P (2020) NBOMes-Highly Potent and Toxic Alternatives of LSD — Frontiers in Neuroscience doi:10.3389/fnins.2020.00078
  5. [5]
    ^Halberstadt AL (2017) Pharmacology and Toxicology of N-Benzylphenethylamine (NBOMe) Hallucinogens — Current Topics in Behavioral Neurosciences doi:10.1007/7854_2016_64
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