4′-Methyl-α-pyrrolidinobutiophenone, also known as MPBP, is a stimulating compound that has emerged as a novel designer drug. It bears a close chemical relationship to pyrovalerone, essentially its homologue with a shorter carbon chain.

IUPAC name
CAS Number732180-91-5
PubChem CID57486975
Chemical and physical data
Molar mass231.339 g·mol−1

Legal status

Legal status
Legal statusCA: Schedule I DE: NpSG (Industrial and scientific use only) UK: Class B


1. What is 4′-Methyl-α-pyrrolidinobutiophenone (MPBP)?

  • 4′-Methyl-α-pyrrolidinobutiophenone, commonly known as MPBP, is a synthetic compound with stimulant properties. It has gained attention as a novel designer drug.

2. What are the effects of MPBP?

  • MPBP is recognized for its stimulating effects, including increased alertness, energy, and euphoria. Users may also experience heightened sociability.

3. Is MPBP legal?

  • The legal status of MPBP varies by country and region. In some areas, it is classified as a controlled substance and is illegal to manufacture, possess, or distribute without proper authorization. Local regulations should be checked to determine its legal status.

4. What are the health risks associated with MPBP use?

  • Using MPBP can carry various health risks, including an increased heart rate, anxiety, paranoia, and potential addiction. Long-term effects are not well understood due to limited research.

5. Can MPBP be detected in drug tests?

  • MPBP can potentially be detected in drug tests, especially in urine tests. However, its inclusion in standard drug screenings may vary. Specialized tests may be necessary for its detection.

6. Are there any street names for MPBP?

  • Street names for MPBP may vary by region and include nicknames or slang terms used by individuals in the illicit drug trade.

7. Is MPBP used for any medical purposes?

  • MPBP is not approved for any medical use and is primarily encountered as a recreational or illicit substance.

8. What should I do if I suspect someone is using MPBP?

  • If you suspect someone is using MPBP or any other illicit substance, it’s essential to encourage them to seek professional help. Substance abuse can have severe health and social consequences, and early intervention is crucial.


  1. Peters FT, Meyer MR, Fritschi G, Maurer HH (September 2005). “Exploring the Metabolism and Toxicological Detection of the Novel Designer Substance 4′-methyl-alpha-pyrrolidinobutyrophenone (MPBP) in Rat Urine Using Gas Chromatography-Mass Spectrometry.” Published in the Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences. Volume 824, Issues 1–2, Pages 81–91. DOI: 10.1016/j.jchromb.2005.07.003. PMID 16046201.
  2. Peters FT, Meyer MR, Theobald DS, Maurer HH (January 2008). “Unveiling the Cytochrome P450 Enzymes Involved in the Metabolism of the Emerging Designer Drug 4′-methyl-alpha-pyrrolidinobutyrophenone.” Published in Drug Metabolism and Disposition. Volume 36, Issue 1, Pages 163–168. DOI: 10.1124/dmd.107.017293. PMID 17962373. S2CID 22230363.

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