Kratom, like any plant grown in soil, can absorb heavy metals — lead, arsenic, cadmium, and mercury — from the ground it's cultivated in. That's why heavy-metal testing is one of the most important checks on a Certificate of Analysis. Here's why these metals end up in kratom, what the test results mean, and how to read them.
This is the kind of thing you can't see, smell, or taste. Only a laboratory can catch it. Understanding what the numbers mean helps you judge whether a product is genuinely clean.
Why heavy metals end up in kratom
Kratom (Mitragyna speciosa) grows in tropical soil in Southeast Asia. Plants naturally pull minerals up through their roots — and if the soil contains heavy metals, some of those come along too.
Heavy metals get into soil through natural geology, industrial pollution, contaminated water, and agricultural practices. A plant grown in clean soil will have low levels; a plant grown in contaminated ground can accumulate more. Because kratom is an agricultural product from varied sources, testing each batch is the only way to know for sure.
This isn't unique to kratom — heavy-metal testing is standard for many botanicals, supplements, and even foods like rice and chocolate. Kratom is simply held to the same reasonable standard.
The four metals that get tested
A proper heavy-metals panel screens for four specific elements:
Lead. The most well-known concern. Lead accumulates in the body over time and offers no safe benefit. Low lead is a key marker of a clean product.
Arsenic. A naturally occurring element that can be present in soil and groundwater. Tests usually measure total arsenic.
Cadmium. Found in some soils and industrial areas. Like lead, it accumulates in the body over time.
Mercury. Less common in plant products but still screened as part of a complete panel.
Together, these four make up the standard heavy-metals test for botanical products.
How the results are reported
Heavy-metal results are typically reported in very small units — usually parts per million (ppm) or parts per billion (ppb), or sometimes as micrograms per gram or per daily serving. Lower numbers are better.
The key thing to understand: the results are compared against limits. Regulated states and testing standards set maximum allowable levels for each metal. A result "below the limit" or "below detectable levels" means the product passed. Some COAs will show the actual measured number alongside the allowed maximum, so you can see the margin.
You don't need to memorize the exact limits. What you're looking for is a clear result showing the metals were measured and came in under the allowed thresholds — or weren't detected at all.
What "below detectable limits" means
You'll often see results listed as "ND" (not detected), "BDL" (below detectable limit), or "<" followed by a small number. These are good signs. They mean the lab looked for the metal and either found none, or found less than the smallest amount its equipment can measure.
This is the ideal result. It doesn't necessarily mean zero atoms of the metal exist — that's nearly impossible for any natural product — but it means the level is so low it's below what sensitive lab equipment can even detect.
Why per-batch testing matters here specifically
Heavy-metal content depends on where and how a specific batch of leaf was grown. Two batches of the same strain, from different harvests or regions, can have different heavy-metal profiles.
This is exactly why a generic or old COA isn't good enough for heavy metals. The report needs to correspond to the actual batch you're buying, identified by a lot number. A vendor testing every batch — and tying each COA to a lot number on the pouch — is giving you the real assurance. A vendor showing one old lab report for all their products is not.
Red flags
Be cautious if:
- The COA omits heavy-metal testing entirely and only shows alkaloids
- The heavy-metal results are vague or don't name the four metals
- The COA can't be matched to a lot number on your product
- The vendor won't provide a batch-specific report on request
Clean heavy-metal results are a baseline expectation for any product you intend to consume — not a premium feature.
How Rimba handles heavy metals
Every batch we sell is screened for lead, arsenic, cadmium, and mercury as part of its third-party lab test. Each pouch carries a lot number that matches its Certificate of Analysis, so the heavy-metal results you see correspond to the exact product in your hands — not a generic sample. If you'd like to review the report for a batch before ordering, just ask.
We are not making any health claim here. We're simply telling you what's in the bag and confirming it was grown and processed in conditions that kept it clean. What you do with that information is your decision.
Not for human consumption. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Must be 21 years or older to purchase.