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Heavy metal

Heavy metal is an outdated term for potentially toxic metallic elements, including lead, arsenic, cadmium, and mercury, that can contaminate a product during manufacturing. Modern lab testing uses the more precise term "elemental impurities."

Also called: heavy metals, elemental impurities, heavy metals screen, heavy metals testing

Heavy metals are toxic metallic contaminants with no biological role in the human body that can enter products during manufacturing. Although the International Union of Pure and Applied Chemistry (IUPAC) considers the term scientifically inconsistent due to varying definitions, regulators like the FDA, EMA, and USP now use the term elemental impurities to focus on actual toxicological risk.

Modern testing methods for elemental impurities

  • Testing has evolved from the limited colorimetric screens of USP <231> to Inductively Coupled Plasma Mass Spectrometry (ICP-MS), which breaks a sample into elemental atoms to measure them at parts-per-billion sensitivity.
  • Modern laboratory analysis specifically targets four primary toxic metals: lead, arsenic, cadmium, and mercury.
  • In a dataset of over 1,200 peptide samples, 17% were found to contain detectable toxic metals exceeding USP safety limits.
  • A high-quality lab report should confirm the use of ICP-MS and demonstrate compliance with ICH Q3D or USP <232> limits.

The difference between toxic contaminants and essential minerals

A common misunderstanding is classifying all metals as heavy metal contaminants. In reality, many metals are essential trace elements that your body requires for health, such as iron, zinc, and copper. In laboratory testing, the term heavy metal refers specifically to toxic metallic contaminants with no biological role, rather than every metal detected in a sample.

Sources

  2. Trace Elements and Metals - LiverTox® - NCBI Bookshelf
  4. [PDF] Elemental Impurities in Drug Products Guidance for Industry - FDA
  5. Investigations of the Copper Peptide Hepcidin-25 by LC-MS/MS and NMR +
  6. Heavy Metals - StatPearls - NCBI Bookshelf
  7. 14 Trace Elements
  8. On-line monitoring of water quality with a floating microbial fuel cell biosensor: field test results
  9. Multi-shell model of ion-induced nucleic acid condensation
  10. [Characteristics and Dominant Influencing Factors of the Fungal Community Structure in Soils Co-contaminated with Rare Earth Elements and Heavy Metals]
  11. Heavy Metal Testing in Peptides | Imperial Peptides UK
  12. Elemental Impurities - Certified Ref. Materials
  13. Heavy metals - Wikipedia
  14. © 2025 USPC - 233 ELEMENTAL IMPURITIES<span class='mdash_char'>—</span>PROCEDURES
  15. ELEMENTAL IMPURITIES—LIMITS
  16. [PDF] “HEAVY METALS”—A MEANINGLESS TERM?
  17. From Heavy Metals Testing to the Measurement of Elemental Impurities in Pharmaceuticals: Over 100 Years in Making the Change | Spectroscopy Online
  18. ACS Peptide Testing Labs - Professional Third-Party Peptide Analysis Services