25B-NBOH
25B-NBOH is a potent serotonergic psychedelic phenethylamine, the N-(2-hydroxybenzyl) derivative of 2C-B. Active in the low milligram to sub-milligram range, it is usually taken sublingually or buccally because it is poorly absorbed orally. Human data is limited to anecdotal reports and forensic case work; no controlled clinical studies exist, and its narrow margin between active and toxic doses makes accidental overdose a real hazard.
01 Overview
25B-NBOH belongs to the NBOH family of N-benzyl phenethylamines, close relatives of the better-known NBOMe series. Like the NBOMes it is a highly potent 5-HT2A agonist, so tiny differences in dose produce large differences in effect. It is frequently sold on blotter and can be visually indistinguishable from LSD or 25x-NBOMe blotter, which has led to misidentification and unintended high-potency exposures.
Almost nothing is known about its human pharmacology or toxicology from formal study. The NBOH and NBOMe classes as a whole carry documented risks of intense vasoconstriction, seizures, hypertension, hyperthermia and, in NBOMe cases, deaths; 25B-NBOH should be treated as sharing that danger profile given how little characterisation exists. Its narrow safety margin means that dosing errors, common with unregulated blotter, can be dangerous.
02 Mechanism
Potent agonist at serotonin 5-HT2A receptors, the shared mechanism of classical psychedelics; the N-benzyl group greatly increases receptor affinity relative to the parent 2C-B.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Threshold | 200–400 mcg | Sublingual | First noticeable effects; individual sensitivity varies widely and blotter dosing is imprecise. |
| Common | 500–1500 mcg | Sublingual | Anecdotal range; not clinically validated. Poor oral bioavailability means it is held in the mouth. |
| Strong | 1500–2500 mcg | Sublingual | Higher doses sharply increase risk of adverse effects; margin is narrow. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Visual distortionColour enhancement, geometric patterning and visual movement reported by users. | strong | Anecdotal | |
| Altered mood and cognitionEmotional and cognitive shifts typical of serotonergic psychedelics. | Anecdotal | ||
| StimulationPhysical stimulation and increased energy commonly reported with NBOH/NBOMe-type compounds. | Anecdotal |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Anxiety and confusionOverwhelming or frightening experiences, especially with unexpected potency. | Moderate | Common | Anecdotal | |
| Peripheral vasoconstrictionMarked narrowing of blood vessels causing cold, painful extremities; in the related NBOMe class this has contributed to tissue ischaemia. | Severe | Common | Anecdotal | |
| SeizuresConvulsions have been reported across the NBOH/NBOMe families, particularly after high or accidental overdoses. | Life-threatening | Uncommon but documented in the class | Anecdotal |