Synthetic cathinones
3-MMC · 3MMC · 3-methylmethcathinone · 4-CMC · 4CMC · clephedrone · MDPHP · pyrrolidino-cathinones · monkey dust
What does current UK evidence show?
The ACMD assessment published in February 2025 documents UK detections of 3-MMC and 4-CMC in submitted and seized samples, and MDPHP in seizures and post-mortem evidence. Much of the underlying analytical material covers 2019–2023, with other streams extending into 2024. MDPHP-related concerns are particularly localised around North Staffordshire; they cannot be generalised to every UK area. EUDA reports continuing European cathinone supply and mis-selling, but these European signals do not establish a UK-wide increase.
Overview
Identity, legal classification, form and pharmacological context
- Drug category
- Stimulants · Synthetic drugs
- Common names
- 3-MMC, 3MMC, 3-methylmethcathinone, 4-CMC, 4CMC, clephedrone, MDPHP, pyrrolidino-cathinones, monkey dust
- Typical forms
- Usually powders or crystals; capsules, tablets and mixtures also occur. Colour, texture and a seller’s description cannot distinguish 3-MMC from mephedrone or identify a pyrrolidino-cathinone.
- Routes
- Swallowed or snorted; some compounds, particularly those sold as monkey dust, may be smoked. Injecting also occurs. The route distribution differs by compound and local population.
- UK legal classification
- Class B3-MMC, 4-CMC and MDPHP are captured by the existing generic cathinone controls and are Class B, Schedule 1 drugs. The relevant generic Class B control commenced on 16 April 2010. The September 2026 government response accepted retaining this classification. Proposed extensions for additional structures do not change the current status of these three drugs; a September 2026 draft Order is not yet in force at this review. Other cathinones can have different controls or exemptions.Check government source ↗
- Concise pharmacology
- These drugs increase monoamine signalling through actions on dopamine, noradrenaline and serotonin transporters. The balance differs: 3-MMC is not pharmacologically identical to mephedrone, and pyrrolidino compounds such as MDPHP have a different stimulant profile. Family membership does not establish equivalent potency or duration.
Main harms
Concise clinical and polydrug picture
Agitation, anxiety, rapid heart rate, high blood pressure and chest pain can occur. Severe poisoning can involve overheating, seizures, psychosis and muscle breakdown. Analytically investigated MDPHP cases describe psychiatric, neurological and cardiorespiratory symptoms. Clinical severity cannot be inferred from the sold name or from a routine negative drug screen.
Repeated use may bring sleep disruption, deteriorating mental health and compulsive use. Compound-specific long-term human evidence is incomplete. Persistent symptoms require assessment for the drug’s effects, other substances, sleep deprivation and co-occurring conditions, rather than automatic attribution to one cathinone.
Craving and difficulty stopping are reported, including with 3-MMC. Post-use fatigue and low mood need individual assessment. Evidence does not justify applying one withdrawal syndrome or detoxification schedule to the entire family.
Other stimulants can compound cardiovascular strain and overheating; serotonergic combinations may increase toxicity. Alcohol, opioids or sedatives can obscure the clinical picture. Products sold as another stimulant may contain a cathinone, so a history based solely on the purchased name can be misleading.
Snorting can injure nasal tissue. Injecting adds bacterial infection, vein damage and blood-borne virus risks; frequent repeat use increases opportunities for harm. Smoking can cause burns and airway exposure. Analytical identification requires suitable methods and reference standards.
Current intelligence status
Assessment, confidence and direction
The ACMD assessment published in February 2025 documents UK detections of 3-MMC and 4-CMC in submitted and seized samples, and MDPHP in seizures and post-mortem evidence. Much of the underlying analytical material covers 2019–2023, with other streams extending into 2024. MDPHP-related concerns are particularly localised around North Staffordshire; they cannot be generalised to every UK area. EUDA reports continuing European cathinone supply and mis-selling, but these European signals do not establish a UK-wide increase.
Reason: Moderate confidence in confirmed UK presence and clinically important stimulant toxicity. Confidence is lower in current market reach, comparative risks between compounds and direction of travel. Sample submissions are voluntary, seizure activity changes, and some laboratory results cannot distinguish closely related isomers. These sources should be triangulated locally rather than combined into a prevalence estimate.
Principal source limits: Submitted samples, seizures, emergency presentations and post-mortem findings have different denominators. The page update in September 2026 does not make all underlying evidence 2026 data. Acceptance of proposed extensions is not itself legislation; current controlled cathinones remain Class 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.Signals justify continued monitoring, but current evidence does not support a formal escalation assessment.
Operational implications
Evidence-supported prompts for professional response
Commissioners should check that stimulant, mental-health, housing and harm-reduction pathways accept people using cathinones. Frontline teams should document purchased name, suspected compound, route and co-use separately. Emergency services should prioritise overheating, chest pain, seizures and severe agitation. Link unusual clusters to local early-warning and laboratory services without describing isolated detections as a national epidemic.
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.
Send unexpected products or incidents through agreed testing and alert routes; distinguish confirmed results from preliminary reports.
Related intelligence
Continue into connected platform evidence
Sources & limitations
Direct evidence links, reference periods and status
Synthetic cathinones: an updated harms assessment
Published3 Feb 2025; government response added 10 Sep 2026Reference periodUK evidence largely 2019–2024; periods differ between datasets
Submitted samples, seizures, emergency presentations and post-mortem findings have different denominators. The page update in September 2026 does not make all underlying evidence 2026 data.Response to ACMD synthetic cathinones assessment
PublishedLetter dated 7 Sep 2026; published 10 Sep 2026Reference periodGovernment response to 2025 recommendations
Acceptance of proposed extensions is not itself legislation; current controlled cathinones remain Class B.Misuse of Drugs Act 1971 (Amendment) Order 2010, SI 2010/1207
Published12 Apr 2010Reference periodCommenced 16 Apr 2010
Introduced the relevant generic Class B control. Some other cathinones have separate controls or exemptions; this is not a claim that every cathinone is Class B.Risk assessment of 3-methylmethcathinone (3-MMC)
Published17 Mar 2022Reference periodRisk assessment conducted 18 Nov 2021
European and international clinical evidence; findings for 3-MMC cannot be assumed to apply identically to 4-CMC or MDPHP.Clinical manifestations and analytical reports for MDPHP acute intoxication cases
Published2024Reference periodAnalytically investigated Italian clinical cases
Selected acute intoxications support a hazard signal, not the frequency of harm among people using MDPHP or UK prevalence.New psychoactive substances: the current situation in Europe
PublishedJune 2026Reference periodEuropean Drug Report 2026; most supply data refer to 2024–2025
European market signals and survey findings must not be relabelled as UK prevalence, UK growth or UK law.