Research chemicalResearch chemicalPhenethylaminePsychedelic

25I-NBOH

Also known as NBOH-2C-I · 2C-I-NBOH · Cimbi-27

Written by enwyReviewed 5 Aug 20261 sources0 comments

25I-NBOH is a potent serotonergic psychedelic, the N-(2-hydroxybenzyl) derivative of 2C-I. Active in the sub-milligram to low milligram range and usually taken sublingually or on blotter, it is the hydroxy analogue of the notorious 25I-NBOMe. Human data is limited to anecdotal reports and forensic case work; its narrow margin between active and harmful doses makes accidental overdose a genuine risk.

01 Overview

25I-NBOH is one of the most commonly encountered NBOH compounds and is frequently sold on blotter, where it can be mistaken for LSD or 25I-NBOMe. As a high-affinity 5-HT2A agonist it is active at very low doses, so small dosing errors translate into large changes in effect and risk.

There is very little formal pharmacology or toxicology in humans. The closely related NBOMe series is associated with severe vasoconstriction, seizures, agitation, hyperthermia and multiple deaths; 25I-NBOH should be assumed to carry comparable dangers given the shared 5-HT2A mechanism and the absence of safety data. The narrow safety margin makes it particularly hazardous when the dose is unknown.

02 Mechanism

Potent agonist at serotonin 5-HT2A receptors; the N-2-hydroxybenzyl group markedly increases 5-HT2A affinity relative to the parent 2C-I.

03 Dosing

Tier	Dose	Route	Notes
Threshold	100–300 mcg	Sublingual	First noticeable effects; sensitivity varies and blotter dosing is imprecise.
Common	500–1500 mcg	Sublingual	Anecdotal range; poor oral bioavailability means it is held sublingually. Not clinically validated.
Strong	1500–2500 mcg	Sublingual	Higher doses sharply raise the risk of severe adverse effects.

04 Effects

Effect	Magnitude	Evidence
Visual distortionBright colour enhancement, patterning and visual movement reported by users.	strong	Anecdotal
Altered mood and cognitionEmotional and cognitive shifts typical of classical psychedelics.		Anecdotal
StimulationPhysical stimulation and restlessness commonly reported with N-benzyl phenethylamines.		Anecdotal

05 Side effects

Effect	Severity	Frequency	Evidence
Peripheral vasoconstrictionCold, painful extremities from marked vasoconstriction; the related NBOMe class has caused ischaemic injury.	Severe	Common	Anecdotal
Hyperthermia and hypertensionElevated body temperature and blood pressure reported in NBOMe/NBOH toxicity, sometimes with tachycardia.	Severe	Uncommon	Anecdotal
Seizures and agitationConvulsions, severe agitation and delirium have been reported across the NBOH/NBOMe families after overdose.	Life-threatening	Uncommon but documented in the class	Anecdotal

06 Legal status

United Kingdom

Class A / Psychoactive Substances Act

N-benzyl phenethylamines are controlled. · as of Jan 2026

United States

Possibly controlled as an analogue

May be treated as a controlled substance analogue under the Federal Analogue Act. · as of Jan 2026

07 References

25I-NBOH and NBOH-series toxicologyPubMed search

08 Discussion0 comments

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This page is reference information, not medical advice. Doses and protocols are documented as they appear in the clinical literature and in practice — describing them is not a recommendation to use them. Countermeasures listed here are not a substitute for a physician. Legal status varies by jurisdiction and changes.