25E-NBOH (NBOH-2C-E): Complete Toxicology, Metabolism & Safety Monograph

25E-NBOH (NBOH-2C-E): Complete Toxicology, Metabolism & Safety Monograph

Emergency psychedelic/serotonergic toxicity: Seizure, dangerous overheating, severe agitation/confusion, loss of consciousness, severe muscle rigidity/clonus, chest pain, collapse, or behavior creating immediate risk of serious injury after an unknown psychedelic requires urgent medical care.

Quick answer

25E-NBOH is a highly potent serotonergic psychedelic in the NBOH family, structurally derived from 2C-E.

It should not be treated as:

• 2C-E;
• 25E-NBOMe;
• 25I-NBOH;
• LSD.

Its direct human evidence remains small but clinically meaningful.

The strongest published case involved a 23-year-old man with serotonergic toxicity and loss of consciousness after taking powder labeled as 25I-NBOH.

Laboratory testing found:

• 25E-NBOH, not 25I-NBOH;
• MDPHP, a potent stimulant cathinone.

That case simultaneously demonstrates severe toxicity, product mislabeling, and the difficulty of assigning causation in mixed-NPS exposure.

Identity

History

25E-NBOH emerged from medicinal-chemistry research into N-benzyl phenethylamines designed to explore high-affinity serotonin receptor ligands.

The NBOH series differs from the better-known NBOMe family by replacing the 2-methoxybenzyl group with a 2-hydroxybenzyl group.

25E-NBOH later entered recreational NPS markets and has been identified in seized materials and human toxicology.

By the early 2020s it was appearing in international early-warning exercises and forensic laboratories.

25E-NBOH vs 2C-E

25E-NBOH is derived from the 2C-E phenethylamine scaffold but is not simply another name for 2C-E.

Adding the N-hydroxybenzyl substituent substantially changes receptor affinity.

The 2026 metabolism study also confirmed 2C-E as one metabolite of 25E-NBOH.

That creates an important forensic distinction:

Finding 2C-E in a specimen does not always prove that 2C-E itself was the original drug consumed if 25E-NBOH exposure is plausible.

25E-NBOH vs 25E-NBOMe

These are different N-benzyl substitutions.

• NBOH: hydroxybenzyl.
• NBOMe: methoxybenzyl.

Related structures do not establish:

• equal potency;
• equal duration;
• equal metabolism;
• equal toxicity.

Evidence from 25E-NBOMe is useful only as class context.

Pharmacology

Medicinal-chemistry studies identify 25E-NBOH among extremely high-affinity 5-HT2A receptor ligands.

5-HT2A agonism is the principal mechanism underlying classic psychedelic effects.

The NBOH family also shows activity at other serotonin 5-HT2 receptor subtypes.

What receptor potency does not tell us

It does not establish:

• a safe human dose;
• an LSD-equivalence ratio;
• a toxic concentration;
• a therapeutic window.

Extremely high receptor affinity makes product concentration/identity important, but it does not justify consumer dosing guidance.

Direct human severe-intoxication evidence

A 23-year-old man consumed powder sold as 25I-NBOH.

He developed:

• a serotonergic syndrome;
• loss of consciousness.

LC-HRMS analysis confirmed:

• 25E-NBOH;
• MDPHP;
• no 25I-NBOH.

Measured concentrations included:

• 25E-NBOH plasma: 2.3 ng/mL;
• 25E-NBOH urine: 25.7 ng/mL;
• MDPHP plasma: 3.4 ng/mL;
• MDPHP urine: 30.5 ng/mL.

Why the MDPHP co-exposure matters

MDPHP can itself cause:

• tachycardia;
• hypertension;
• agitation;
• hyperthermia;
• psychiatric toxicity.

Therefore the human case establishes that 25E-NBOH was present during severe poisoning, but it cannot prove every feature was caused by 25E-NBOH alone.

This distinction is essential.

Product mislabeling

The powder was labeled 25I-NBOH.

25I-NBOH was specifically searched for and not detected.

That gives unusually direct evidence that:

A research-chemical label can name the wrong psychedelic even within the same NBOH family.

The buyer may not know which substitution is present.

Serotonergic toxicity

25E-NBOH's 5-HT2A agonism makes serotonergic toxicity biologically plausible.

The human case was clinically described as a serotonergic syndrome.

Potential severe features can include:

• agitation;
• autonomic instability;
• hyperthermia;
• clonus;
• altered consciousness;
• seizure.

Because MDPHP was also present, the incidence and exact phenotype of isolated 25E-NBOH toxicity remain unknown.

NBOH-class severe toxicity

Direct 25B-NBOH human cases provide useful class context.

A five-person poisoning cluster after powder sold as “LSD” included:

• severe agitation;
• tachycardia;
• hypertension;
• status epilepticus;
• acute kidney injury;
• rhabdomyolysis.

In the two severe cases, 25B-NBOH was analytically detected without other illicit/licit drugs.

Those findings demonstrate that the NBOH class can produce severe physiologic toxicity.

They do not establish the same incidence or threshold for 25E-NBOH.

Seizures, hyperthermia and rhabdomyolysis

These complications are plausible concerns with potent N-benzyl phenethylamines.

For genuine isolated 25E-NBOH, published human frequency is not established.

A seizure, dangerous overheating or severe muscle rigidity after an unknown NBOH is emergency-level toxicity.

Cardiovascular effects

5-HT2A agonism and severe serotonergic/sympathomimetic states can involve:

• tachycardia;
• hypertension;
• vasoconstriction;
• cardiac stress.

There is no validated 25E-NBOH cardiovascular-risk threshold.

Fatalities: what is and is not established

This review does not identify a well-documented isolated 25E-NBOH fatality series in the peer-reviewed evidence used here.

That should not be translated into “25E-NBOH cannot be fatal.”

The human evidence base is simply too small to define:

• fatality incidence;
• a lethal dose;
• a fatal blood concentration.

Related NBOMe/NBOH compounds have caused severe and fatal intoxications, but those data should not be silently reassigned to 25E-NBOH.

Human metabolism: first authentic case

The 2024 clinical case provided the first authentic-human metabolism data.

Researchers described seven metabolites:

• two phase-I metabolites;
• five phase-II metabolites.

One conjugated metabolite was especially abundant in both plasma and urine and was proposed as a useful consumption marker.

2026 comprehensive metabolism study

A 2026 Journal of Pharmaceutical and Biomedical Analysis study expanded the metabolic map dramatically.

Researchers used:

• human liver microsomes;
• rat urine;
• the fungus Cunninghamella elegans.

They annotated 56 metabolites, including multiple isomeric products.

Major metabolic pathways

Important pathways included:

• hydroxylation;
• O-demethylation;
• N-debenzylation;
• glucuronidation;
• sulfation;
• other conjugations.

Ten synthesized candidate metabolites were compared directly against analytical signals; seven were successfully matched by retention time and MS/MS spectra.

2C-E as a confirmed metabolite

The 2026 study confirmed 2C-E as one metabolite using a commercial reference standard.

This matters for toxicology because 2C-E may reflect:

• direct 2C-E use;
• metabolism of 25E-NBOH.

Interpretation requires the broader parent/metabolite pattern.

Biomarkers

The 2026 study proposed three principal biomarkers supported by the new and earlier work.

Metabolite-aware testing can:

• improve confidence in exposure;
• extend detection beyond parent drug;
• help separate true intake from analytical noise.

Pharmacokinetics

There is no controlled human 25E-NBOH PK study establishing:

• bioavailability;
• time to peak;
• terminal half-life;
• clearance;
• active-metabolite contribution;
• dose-concentration relationships.

A single patient's plasma concentration cannot answer these questions.

Drug testing

Routine screens

Routine workplace/emergency immunoassays do not specifically identify 25E-NBOH.

A negative amphetamine, LSD, or generic toxicology screen does not exclude an NBOH.

Definitive methods

Published work relies on:

• LC-HRMS;
• UHPLC-Orbitrap MS;
• authenticated reference standards;
• metabolite-aware analysis.

Why parent-only testing can miss the exposure

NBOH/NBOMe compounds can be:

• present at low blood concentrations;
• extensively metabolized;
• outside standard toxicology libraries.

Testing parent plus high-value metabolites increases confidence.

Interactions

No controlled human interaction studies define safe combinations.

Important concerns include:

• MAO inhibitors;
• serotonergic stimulants/entactogens;
• other psychedelics;
• stimulants such as cathinones;
• drugs increasing body temperature or cardiovascular load.

The only strong human 25E-NBOH toxicity case already involved a stimulant co-exposure.

Tolerance

Classic serotonergic psychedelics can develop rapid pharmacodynamic tolerance.

25E-NBOH-specific human tolerance studies do not exist.

Cross-tolerance with:

• LSD;
• 2C-E;
• NBOMes;
• other NBOHs

is biologically plausible but not quantified.

Tolerance should not be used as a reason to escalate exposure.

Physical dependence and addiction

There is no established 25E-NBOH physical-dependence syndrome comparable with opioids, alcohol or benzodiazepines.

Population-level use-disorder data are absent.

That does not mean repeated use is harmless.

Potential repeated-use harms include:

• psychiatric destabilization;
• repeated mislabeling exposure;
• risky behavior;
• persistent perceptual symptoms in susceptible people.

Withdrawal

No validated 25E-NBOH withdrawal syndrome or timeline exists.

This absence should be stated explicitly rather than filled with generic withdrawal claims.

Treatment and support

There is no 25E-NBOH-specific antidote.

Severe acute poisoning is managed according to clinical complications such as:

• seizure;
• hyperthermia;
• severe agitation;
• cardiovascular instability;
• reduced consciousness;
• trauma.

Persistent psychiatric symptoms or harmful repeated use warrant medical/mental-health care.

Forensic interpretation

Product label does not establish identity

The strongest human case proves this directly.

Detection does not define causation

MDPHP co-exposure substantially complicates the severe case.

2C-E can be a metabolite

A 2C-E finding needs parent/metabolite context.

Concentration is not dose

The reported 2.3-ng/mL plasma value is a case observation, not a toxic threshold.

Special populations

No controlled 25E-NBOH safety studies establish risk in:

• pregnancy/breastfeeding;
• adolescents;
• older adults;
• cardiovascular disease;
• seizure disorders;
• bipolar/psychotic disorders;
• liver/kidney disease.

Missing evidence is not evidence of safety.

Legal status — dated October 3, 2026

United States

The current federal schedules reviewed for this article do not specifically list 25E-NBOH by name.

That is not a statement that possession or sale is necessarily lawful.

Potential federal analogue-law and state-law issues can depend on:

• chemical similarity;
• intended human consumption;
• jurisdiction.

International

UNODC currently tracks 25E-NBOH as a phenethylamine / classic hallucinogen NPS.

The UNODC substance record used here does not list a 1961/1971 Convention control status for 25E-NBOH.

Individual national controls vary.

Myths and misconceptions

“25E-NBOH is just 2C-E with predictable potency.”
False.

“NBOH compounds are simply milder NBOMes.”
Not established; severe NBOH poisoning is documented.

“The 2024 case proves 25E-NBOH alone causes serotonin syndrome.”
No. MDPHP was also present.

“A product labeled 25I-NBOH contains 25I-NBOH.”
False in the published 25E-NBOH case.

“Finding 2C-E proves direct 2C-E use.”
Not always; 2C-E is a confirmed 25E-NBOH metabolite.

“No published isolated fatality means the drug is safe.”
False. The direct human dataset is too sparse for that conclusion.

Evidence ledger

Related evidence

• NBOMe / NBOH psychedelic family
• 25I-NBOMe
• 2C-B-FLY
• MDPHP
• RC psychedelics evidence hub
• Substance Use, Dependence & Harm Reduction hub

Bottom line

25E-NBOH now has enough evidence to deserve more than a generic “NBOH psychedelic” stub.

The literature gives us:

• a severe human intoxication;
• direct proof of product mislabeling;
• authentic plasma/urine concentrations;
• a rapidly expanding metabolic map;
• confirmed conversion to 2C-E;
• strong mechanistic reason to take serotonergic toxicity seriously.

What it still does not give us is a safe dose, clean isolated-drug syndrome, human half-life, fatal threshold, or dependence rate.

That uncertainty belongs at the center of the page—not hidden in the footnotes.