{
  "abstract": "Introduction: The United States has seen a rise in methamphetamine use disorders and methamphetamine-involved deaths. However, there is limited information on methamphetamine at the street level. We leverage data from a community-based drug checking program in Los Angeles to investigate the makeup of the retail illicit methamphetamine market and the extent methamphetamine plays a role as an adulterant in other drugs. Methods: Participants accessing a community-based drug checking program provided samples of drug products and completed brief interviews in Los Angeles County, California, from 2023 to 2025. Samples underwent laboratory-based qualitative and quantitative mass spectrometry. We quantitated the presence and concentration of methamphetamine as well as all other identified substances among samples expected only to be methamphetamine and samples expected to be another substance (e.g., fentanyl, heroin) where methamphetamine was found as an adulterant/contaminant. Results: Of N = 2193 total samples, n = 652 (29.7%) were methamphetamine-positive on DART-MS. In samples expected to contain methamphetamine, the mean purity was 78.2% (SD 24.0%; range <1% to ≈100%). As an unexpected component, the mean methamphetamine purity was 17.8% (SD 32.3%) and was mostly found in samples expected to be fentanyl, heroin, other amphetamines. Conclusions: Participants in Los Angeles seeking methamphetamine appear to frequently obtain high-purity samples that are rarely adulterated with other substances, although we observed a wide variation in concentration between samples. In contrast, drugs purchased without the expectation of containing methamphetamine had high prevalence of methamphetamine adulteration/contamination. Future research should expand methamphetamine surveillance techniques and investigate how variability in illicit markets may impact health outcomes.",
  "abstract_shown": true,
  "affiliations": [
    "Division of General Internal Medicine and Health Services Research, Geffen School of Medicine, University of California, Los Angeles, CA, United States.",
    "Dept. of Health Policy & Management, Fielding School of Public Health, University of California, Los Angeles, CA, United States.",
    "Dept. of Anthropology, College of Social Sciences, University of California, Los Angeles, CA, United States.",
    "Homeless Outreach Program's Integrated Care System, Los Angeles, CA, United States.",
    "Bienestar Human Services, Los Angeles, CA, United States.",
    "The Sidewalk Project, Los Angeles, CA, United States.",
    "Community Health Project LA, Los Angeles, CA, United States.",
    "Geffen School of Medicine, University of California, Los Angeles, CA, United States.",
    "University of California, Los Angeles, Los Angeles, CA, United States.",
    "San Luis Obispo County Department of Behavioral Health, San Luis Obispo, CA, United States.",
    "University of California, San Diego, San Diego, CA, United States."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 19,
  "authors": [
    {
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        0,
        1
      ],
      "name": "Adam J Koncsol",
      "orcid": "0000-0001-5984-2577"
    },
    {
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        0
      ],
      "name": "Caitlin A Molina"
    },
    {
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        0
      ],
      "name": "Ruby Romero"
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    {
      "affs": [
        0,
        2
      ],
      "name": "Megan Grabill"
    },
    {
      "affs": [
        0
      ],
      "name": "Morgan E Godvin"
    },
    {
      "affs": [
        3
      ],
      "name": "Jesse Carrizal"
    },
    {
      "affs": [
        3
      ],
      "name": "Manuel Contreras"
    },
    {
      "affs": [
        3
      ],
      "name": "Oscar Arellano"
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    {
      "affs": [
        4
      ],
      "name": "Naomi Villanueva"
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    {
      "affs": [
        5
      ],
      "name": "Elham Jalayer"
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        6
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      "name": "Spider Davila"
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    {
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      "name": "Soma Snakeoil"
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    {
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        7
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      "name": "Joshua Smith"
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    {
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        7
      ],
      "name": "Charles J Santamaria"
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    {
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        7
      ],
      "name": "Leslie Nuñez"
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      "name": "Ezinne Okonkwo"
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        9
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      "name": "Siddarth Puri"
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    {
      "affs": [
        10
      ],
      "name": "Joseph R Friedman"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Chelsea L Shover"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/38hf5n8ttdz9c.bib",
  "cited_by": 2,
  "doi": "10.1016/j.dadr.2026.100482",
  "fulltext_url": "http://www.sciencedirect.com/science/article/pii/S2772724626000752",
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  "language": "en",
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
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  "pmid": "42959904",
  "published": "2026-10-07",
  "publisher": "Elsevier",
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  "title": "Crystal clear: Purity of street-level methamphetamine samples and methamphetamine-adulteration of other drugs in Los Angeles, 2023–2025",
  "title_text": "Crystal clear: Purity of street-level methamphetamine samples and methamphetamine-adulteration of other drugs in Los Angeles, 2023–2025",
  "type": "peer-reviewed",
  "updated_at": "2026-11-02T12:22:39Z",
  "url": "https://research.draconitic.com/paper/38hf5n8ttdz9c",
  "venue": "Drug and Alcohol Dependence Reports",
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