What Is 25I-NBoMe

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Last updated: April 15, 2026

Quick Answer: 25I-NBOMe is a synthetic hallucinogen first synthesized in 2004 by chemist Ralf Heim. It is a potent serotonin receptor agonist, active at doses as low as 500 micrograms, and has been linked to multiple fatalities worldwide.

Key Facts

25I-NBOMe was first synthesized in 2004 by German chemist Ralf Heim
Active dose starts at approximately 500–800 micrograms
It is a potent agonist of the 5-HT2A serotonin receptor
At least 19 deaths were linked to 25I-NBOMe between 2010 and 2015
The compound is illegal in over 30 countries, including the U.S. and UK

Overview

25I-NBOMe is a synthetic psychedelic substance belonging to the phenethylamine class of drugs. It emerged in the early 2010s as a designer drug marketed online and sold as blotter paper, often misrepresented as LSD.

Despite its hallucinogenic effects, 25I-NBOMe is not related to LSD chemically; it is a derivative of the 2C family of phenethylamines. Due to its high potency and narrow safety margin, it has been associated with severe toxicity and fatalities.

Dose range: The active dose of 25I-NBOMe is extremely low, typically between 500 and 800 micrograms, making accidental overdose common.
Synthesis: First created in 2004 by German chemist Ralf Heim during research on serotonin receptor ligands.
Receptor activity: It acts as a highly potent agonist at the 5-HT2A receptor, which mediates its hallucinogenic effects.
Legal status: Classified as a Schedule I controlled substance in the United States since 2013 under temporary emergency scheduling.
Public health impact: Linked to at least 19 deaths globally between 2010 and 2015, with many cases involving young adults under 25.

Pharmacology and Effects

25I-NBOMe interacts primarily with serotonin receptors in the brain, leading to intense sensory and cognitive alterations. Its effects are rapid in onset but can be unpredictable due to variable absorption and potency.

Onset time: Effects begin within 15 to 45 minutes when taken sublingually, peaking at 2–3 hours post-ingestion.
Duration: The psychedelic experience typically lasts between 6 and 10 hours, longer than many other hallucinogens.
Safety margin: The compound has a very narrow therapeutic index, meaning the difference between a psychoactive dose and a lethal one is minimal.
Metabolism: It is metabolized in the liver, primarily by CYP enzymes, leading to potential interactions with other drugs.
Adverse effects: Common side effects include hypertension, tachycardia, seizures, and hyperthermia, even at recreational doses.
Neurotoxicity: Animal studies suggest possible serotonergic neurotoxicity with repeated exposure, though human data is limited.

Comparison at a Glance

Below is a comparison of 25I-NBOMe with similar substances based on potency, legality, and health risks.

Substance	Dose Range	Legal Status (U.S.)	Receptor Affinity (5-HT2A)	Fatalities Reported
25I-NBOMe	500–800 µg	Schedule I	High (Ki = 0.044 nM)	19+
LSD	50–150 µg	Schedule I	High (Ki = 3.5 nM)	Very rare
Psilocybin	10–20 mg	Schedule I	Moderate	Negligible
2C-I	1,500–3,000 µg	Unregulated (not FDA-approved)	Low	Few
DMT	20–60 mg (inhaled)	Schedule I	Moderate	Very rare

While 25I-NBOMe shares hallucinogenic properties with substances like LSD and psilocybin, its higher potency and toxicity profile make it significantly more dangerous. Unlike naturally occurring psychedelics, NBOMe compounds were never intended for human consumption and lack clinical safety data.

Why It Matters

Understanding 25I-NBOMe is critical for public health, harm reduction, and drug policy. Its presence in unregulated markets poses serious risks, especially to adolescents and first-time users unaware of its dangers.

Harm reduction: Many users mistake 25I-NBOMe for LSD due to similar blotter paper formats, increasing risk of accidental overdose.
Emergency response: Overdose cases often require intensive care due to seizures, vasoconstriction, and acute kidney injury.
Forensic challenges: The compound is often undetectable in standard drug screens, delaying diagnosis and treatment.
Legal enforcement: Its status as a designer drug allows it to evade regulation temporarily until new laws are enacted.
Global spread: Detected in over 30 countries, including Australia, Canada, and across Europe, often linked to online sales.
Research implications: Despite its dangers, 25I-NBOMe has contributed to neuroscience research on serotonin receptor function and psychedelic pharmacology.

As synthetic drugs continue to evolve, accurate information and accessible testing are essential to prevent further deaths and support informed decision-making.