Roidipedia.Compound reference & reporting
06 AUG 2026
CompoundsResearch chemical 25B-NBMD
Research chemicalResearch chemicalPhenethylaminePsychedelic5-HT2A agonistN-benzyl (NBMD)

25B-NBMD

Also known as 2C-B-NBMD · NBMD-2C-B

25B-NBMD is the N-(2,3-methylenedioxybenzyl) derivative of 2C-B, a rare member of the NBMD subfamily of N-benzyl phenethylamine psychedelics. It is a potent 5-HT2A agonist sharing the 25x family's narrow safety margin, vasoconstriction and seizure risk.

01 Overview

25B-NBMD substitutes a 2,3-methylenedioxybenzyl group for the NBOMe 2-methoxybenzyl. It is an obscure compound that has been characterised chemically and appears only rarely in the market.

Human data are essentially nonexistent; information is anecdotal and analytical. As with all N-benzyl phenethylamines, the sub-milligram active range and steep dose-response make dosing errors dangerous, and the class hazards of vasoconstriction and serotonergic overstimulation apply.

02 Mechanism

Potent agonist at serotonin 5-HT2A receptors; the N-2,3-methylenedioxybenzyl group confers high 5-HT2A affinity on the 2C-B scaffold.

03 Dosing

TierDoseRouteNotes
Threshold200–500 µgSublingualEstimated; almost no data.
Common500–1500 µgSublingualAnecdotal only.

04 Effects

EffectMagnitudeEvidence
Psychedelic effectsVisuals and cognitive alteration consistent with the 25x-NB class.6-10 hAnecdotal
StimulationBody load and tension.moderateAnecdotal

05 Side effects

EffectSeverityFrequencyEvidenceCountermeasures
VasoconstrictionCold extremities and hypertension.SevereCommonAnecdotal
Seizures and serotonergic toxicityOverdose can cause agitation, seizures and hyperthermia.Life-threateningUncommonAnecdotal

07 References

Structure-activity relationships of N-benzyl phenethylamine 5-HT2A agonistsACS Chemical Neuroscience, 2015
EMCDDA NBOMe overviewEMCDDA

08 Discussion0 comments

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