Of every panel on a kratom certificate of analysis, the kratom heavy metals section is the one most directly about your safety — and the one buyers understand least. Lead, arsenic, cadmium and mercury are genuine, recurring findings in botanical products, kratom included. Here is where they come from, how testing works, and the numbers you should expect a published COA to show.
Why heavy metals end up in kratom
Kratom trees are bioaccumulators: like tea and leafy greens, they draw minerals and contaminants from soil into their leaves. Leaf grown in contaminated soil — naturally mineralized or industrially polluted — carries that load into the milled powder. Drying and milling add nothing; the metals arrive with the leaf. Because kratom supply chains start at thousands of smallholder farms, per-batch testing is the only control that works.
The four metals, and why each matters
- Lead (Pb) — the most common kratom finding; a neurotoxin with no safe exposure threshold, which is why limits are strictest here.
- Arsenic (As) — soil-derived, regionally variable, and worth distinguishing between organic and inorganic forms in a full workup.
- Cadmium (Cd) — accumulates in kidneys over time; a chronic-exposure concern for regular users.
- Mercury (Hg) — rarer in leaf, still standard on every panel.
How labs measure them
The standard method is ICP-MS — inductively coupled plasma mass spectrometry — which ionizes a digested sample and counts metal atoms by mass. It measures down to parts per billion, which is why results appear in ppm (parts per million) with pass/fail limits alongside. Accreditation to ISO/IEC 17025 is the lab-side quality mark; how to verify it is covered in how to read a COA.
The limits a COA should reference
US regulation does not set kratom-specific metal limits, so reputable labs apply food and dietary-supplement reference points — commonly California Prop 65 safe-harbor levels and AHPA botanical guidance, which put lead in the low single-digit ppm at most, often under 1 ppm, with tighter action levels for the others. A COA that shows a number but no limit, or a limit with no standard named, is incomplete — one of the red flags in how to spot a fake lab test.
What a fail looks like, and what happens next
Failed metal results mean the batch never ships — from a GMP-certified operation with documented recall procedures, that is exactly what batch records are for. See why GMP certification matters. The buyer’s version of that system: match your package’s batch number to the published COA before use, every time.
Our testing, stated plainly
Every Pure Ohms batch is screened by an independent ISO-accredited laboratory for heavy metals alongside potency, microbials, residual solvents and adulterants — results published, not summarized, on the lab tests page.
Related reading
- Kratom microbial testing — the other contamination panel.
- How to read a kratom COA — the complete guide.
- Where to buy kratom online — the vendor standard.
These statements have not been evaluated by the FDA. Kratom is not intended to diagnose, treat, cure or prevent any disease. Adults 21+ only.
Ready to order lab-tested kratom?
Every Pure Ohms batch ships with an independent Certificate of Analysis, is manufactured in a GMP-certified facility, and dispatches the same day from the USA. A $120 merchandise minimum applies. Standard shipping is $25 to eligible USA and Canada addresses, and free on merchandise subtotals over $500.