Understanding Heavy Metals in Supplements: What Your COA Shows (and How to Read It)
1. TL;DR
Trace amounts of heavy metals can appear in botanicals and minerals because they come from soil and water. That’s why every batch is screened for lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As). Labs typically use ICP-MS and report results in ppm (mg/kg) or ppb (µg/kg). Your COA should show the method, result, and the specification it was checked against.
2. Why heavy metals show up
- Natural background: Plants absorb minerals—including trace metals—from the environment.
- Processing: Concentrating extracts can also concentrate trace elements.
- Packaging & handling: Good manufacturing controls minimize any added contamination.
Key point: Presence ≠ problem. What matters is how much is present and whether it meets the product’s specification.
3. The four we monitor (Pb, Cd, Hg, As)
| Metal | Why we check it | Typical sources | Notes |
|---|---|---|---|
| Lead (Pb) | Neurotoxic at elevated exposure | Soil, dust, older infrastructure | Reported as ppm or ppb; often lowest-possible limits |
| Cadmium (Cd) | Kidney accumulation risk | Soil; certain crops | Watch concentrated botanical powders |
| Mercury (Hg) | Neurotoxic; methyl-Hg in fish | Marine oils; environment | For plant capsules, usually very low/ND |
| Arsenic (As) | Toxic at higher exposure | Water/soil | Sometimes spec differentiates inorganic As |
4. How labs test (ICP-MS) & units
Method
ICP-MS (inductively coupled plasma mass spectrometry) is the go-to technique for multi-element trace analysis. Samples are digested (acid + heat), atomized in plasma, and quantified by mass spectrometry against certified standards.
Units you’ll see
- ppm = mg/kg = µg/g
- ppb = µg/kg = ng/g
- ND = not detected (below the method’s detection/quantitation limit)
LoD vs. LoQ: LoD is the smallest signal detectable; LoQ is the lowest level you can quantify with confidence. COAs often list one or both.
5. How to read a COA result
- Find the panel: Look for “Heavy Metals,” “Elemental Impurities,” or similar.
- Check the method: ICP-MS (preferred). Method/SOP ID should be listed.
- Compare result vs. spec: The COA should show a Result and a Specification (limit). “Pass/Fail” indicates compliance.
- Convert to per-serving (optional): If your result is in ppm (µg/g), multiply by grams per serving to get µg/serving.
Example: Lead result = 0.25 ppm (i.e. 0.25 µg/g). Capsule fill weight = 0.6 g. Exposure per serving = 0.25 × 0.6 = 0.15 µg.
6. Our internal approach (US)
- Spec drafting: We maintain internal specifications for Pb, Cd, Hg, and As for each product.
- Supplier controls: Supplier qualification + incoming COAs for key raw materials.
- Batch release: Third-party lab testing for finished product before shipment.
- Transparency: See our Lab Tests & Certifications page for the testing overview and document list.
Heads-up: Exact acceptance limits vary by product and internal spec. Always refer to the latest COA for your batch.
7. Quick calculator: ppm → µg per serving
Enter your COA value and serving weight to estimate µg per serving.
Note: This tool is for educational use only. For compliance decisions, rely on the COA and your product specification.
8. FAQs
Is “ND” the same as zero?
No—“not detected” means the analyte was below the method’s detection/quantitation limit.
Why does the COA list arsenic without saying “inorganic”?
Some specs use total arsenic, others specify inorganic arsenic. Your COA or spec will state which applies.
Do mineral ingredients (e.g., zinc, magnesium) affect heavy metal results?
Not directly. The lab method isolates trace impurities. We test each finished batch to verify compliance.
Where can I find the limits?
Limits are defined in our internal specification for each product. Check the “Specification” column on your COA and our lab page for the testing framework.
9. More transparency
Disclaimer: Educational content only; not medical or legal advice. For personal guidance, consult your healthcare professional.