2C-B
2CB · 2C B · Nexus · 4-bromo-2,5-dimethoxyphenethylamine
What does current UK evidence show?
2C-B is an established controlled drug covered by UK public-health information. Current evidence reviewed here does not provide a robust standalone UK prevalence estimate or demonstrate a national increase in harm. Tusi-related reports should not be counted as 2C-B evidence unless analysis actually identifies 2C-B. EUDA explains that tuci and tucibi names derive from the sound of 2C or 2C-B, while tested pink mixtures commonly contain other substances.
Overview
Identity, legal classification, form and pharmacological context
- Drug category
- Psychedelics · Synthetic drugs
- Common names
- 2CB, 2C B, Nexus, 4-bromo-2,5-dimethoxyphenethylamine
- Typical forms
- Most often tablets or powder sold under a drug name or tablet design. Branding, colour and a seller’s assurance do not confirm the chemical or strength. Pink powder sold as tusi may contain no 2C-B at all.
- Routes
- Usually swallowed; powder may be snorted. Route changes the speed and intensity of effects. There is no basis here for describing smoking or injecting as common UK routes for 2C-B.
- UK legal classification
- Class A2C-B (4-bromo-2,5-dimethoxyphenethylamine) is a Class A controlled drug and is listed in Schedule 1 of the Misuse of Drugs Regulations 2001. The Home Office reference explicitly lists the compound. These are existing controls, not a new proposal. Possession, production and supply require an applicable legal authority; small research studies do not create a general treatment or retail exemption.Check government source ↗
- Concise pharmacology
- 2C-B interacts with serotonin receptors, including the 5-HT2A system involved in psychedelic effects. Perception, emotion and thinking can change, alongside stimulant-like effects. A 2026 placebo-controlled study in 24 healthy participants compared acute effects with MDMA and psilocybin; those supervised findings do not establish the safety of street products or unsupervised combinations.
Main harms
Concise clinical and polydrug picture
Anxiety, panic, confusion and distressing perceptual changes can occur, together with nausea, headache and cardiovascular stimulation. Severe agitation or psychiatric symptoms require assessment. Apparent intoxication after a product sold as 2C-B may involve another substance, so clinical decisions should follow the presentation and exposure history rather than a presumed identity.
Long-term, compound-specific human evidence remains limited. Small studies of one supervised exposure cannot exclude persistent psychological problems or harms from repeated use. Continuing perceptual disturbances, insomnia or impaired functioning after an experience should prompt clinical review, including assessment of pre-existing mental-health conditions.
A predictable physical withdrawal syndrome has not been established. Evidence on dependence is sparse, so absence of a recognised syndrome should not be interpreted as absence of problematic use. Assess frequency, loss of control, recovery between episodes and effects on daily life.
Combining 2C-B with other psychoactive drugs can make psychological and physical effects less predictable. Other stimulants can add cardiovascular burden. Evidence is insufficient to assign precise risks to every medicine combination; a medicines history and clinical advice are preferable to treating all psychedelics as interchangeable.
Snorting can be painful and injure nasal tissue. Uncertain identity and strength create additional risk regardless of route. Products sold as tusi require a separate contents-based assessment because ketamine, MDMA or other ingredients bring their own harms and interactions.
Current intelligence status
Assessment, confidence and direction
2C-B is an established controlled drug covered by UK public-health information. Current evidence reviewed here does not provide a robust standalone UK prevalence estimate or demonstrate a national increase in harm. Tusi-related reports should not be counted as 2C-B evidence unless analysis actually identifies 2C-B. EUDA explains that tuci and tucibi names derive from the sound of 2C or 2C-B, while tested pink mixtures commonly contain other substances.
Reason: Moderate confidence in the drug’s identity, legal control and acute effects, supported by public-health guidance and small controlled studies. Confidence is lower for long-term outcomes, current UK exposure and combination risks. Selected laboratory samples, reports of intoxication and international studies describe different populations and cannot be combined into a UK trend.
Principal source limits: A non-exhaustive reference; generic controls also apply. Lists 2C-B and N,N-dimethyltryptamine as Class A, Schedule 1. Discusses a drug family; not all statements establish compound-specific frequency, duration or harms for 2C-B.
Geography and reference periods are given in each linked source card below. The rating is an editorial evidence judgement, not a probability, clinical risk score or TD priority.The assessment reflects the latest linked evidence and is not a universal severity rating.
Operational implications
Evidence-supported prompts for professional response
Treatment and emergency teams should explicitly ask whether the person means confirmed 2C-B, a tablet sold as 2C-B, or pink powder sold as tucibi. Record that distinction in incident reports. Commissioners should maintain accessible assessment and psychological support without inferring high population demand from social-media interest. Severe confusion, seizures, chest pain or collapse should trigger urgent medical care.
Record substance, sold identity, route, frequency and combinations; review physical, mental-health and dependence needs.
Use symptom-led assessment and escalate reduced consciousness, seizures, overheating, chest pain or severe agitation.
Triangulate treatment, mortality, testing, hospital and frontline evidence before assigning a local trend.
Related intelligence
Continue into connected platform evidence
Sources & limitations
Direct evidence links, reference periods and status
List of commonly encountered drugs controlled under misuse of drugs legislation
PublishedUpdated 1 Apr 2025Reference periodClassification and scheduling checked 12 Oct 2026
A non-exhaustive reference; generic controls also apply. Lists 2C-B and N,N-dimethyltryptamine as Class A, Schedule 1.2C family: effects, risks and UK law
PublishedSource page undatedReference periodUK public health information accessed 12 Oct 2026
Discusses a drug family; not all statements establish compound-specific frequency, duration or harms for 2C-B.Acute dose-dependent effects of 2C-B compared with MDMA and psilocybin
Published28 Apr 2026Reference periodRandomised double-blind placebo-controlled crossover study; 24 healthy participants
A small, screened and supervised healthy-volunteer study cannot establish safety of unregulated products, combinations or long-term use.Assessment of the acute effects of 2C-B versus psilocybin on subjective experience, mood and cognition
Published2023Reference periodDouble-blind crossover study; 22 healthy participants
A small acute study, not a UK prevalence measure or long-term safety study.EU drug market: MDMA — retail markets; What is tucibi?
PublishedMarch 2025Reference periodEuropean drug-market and analytical evidence
Tusi is a variable mixture. European submitted and seized samples do not establish a fixed recipe or UK prevalence.