All Swanson products are tested for heavy metals. The heavy metal limits are listed below.


  • Lead: 2.75 µg/maximum daily dose
  • Arsenic: 10 µg/maximum daily dose
  • Cadmium: 4.1 µg/maximum daily dose
  • Mercury: 0.3 µg(organic)/maximum daily dose
  •  3 µg(inorganic)/maximum daily dose


The maximum daily dose must be based on the maximum daily dose on product label.  Swanson's manufacturers are required (in accordance with cGMP) to quality control test each batch and provide certificate of analysis. 


Swanson also do quality control testing and retain samples of each batch of product. Additionally, depending on manufacturers track record as far as quality of production, random batches are tested by 3rd party laboratories as well. 


Swanson's standing with being audited and in line with cGMP is the customers verification that their products are compliant with the GMP requirements for quality control testing on the products.