If questions about heavy metals in matcha have found their way into your morning routine, you deserve a straight answer rather than more noise. The conversation has grown louder over the past year, and a good portion of what's circulating online lands somewhere between incomplete and genuinely misleading (ie - trending fearmongering). We think it’s worth addressing the subject with the research and precision it deserves. The useful questions are how much, from where, and whether the sourcing practices behind your matcha account for any potential.
Here’s what the science says, what it doesn't say, and what heavy metals mean for the matcha in your cup.
What Are Heavy Metals and Why Do They Appear in Food?
Heavy metals are naturally occurring elements found in the Earth's crust. Lead, arsenic, cadmium, and mercury are the four most commonly tested in food and tea. They are present in soil at trace levels across virtually every agricultural region of the world, and crops absorb them through their root systems as part of normal growth, just as they absorb water and minerals. This is true of leafy vegetables, grains, root vegetables, fruits, herbs, and tea.
The presence of trace amounts of heavy metals in food is not, in itself, evidence of contamination or negligence; it’s a function of how plants grow. What matters is the concentration, which is shaped by the history of the soil: whether it’s been affected by industrial activity, proximity to roads, the use of certain fertilizers, or simple geographic proximity to naturally occurring mineral deposits. Regions with clean agricultural histories and well-regulated farming practices produce crops with lower levels of contamination. Regions with industrial legacies or poor oversight produce higher ones.
This is why the conversation about heavy metals in food ultimately comes down to sourcing.
Why Matcha Demands a Higher Sourcing Standard Than Any Steeped Tea
With matcha, the entire tencha leaf is stone-ground into fine powder and suspended directly in water. You drink the whole leaf. The same mechanism that concentrates EGCG and L-theanine in each bowl also means any trace metals in the leaf are ingested fully rather than left behind. That is why the sourcing standards, farming practices, and testing rigor for matcha require a level of scrutiny that exceeds what any steeped tea demands. The bar is simply higher because the method of consumption is different.
"Trace" is worth defining because the word does the work here. A trace level is a measurement in the range of micrograms per kilogram, sometimes less. To put that in perspective, a daily one-gram serving of ceremonial-grade matcha from a well-tested Japanese source delivers a lead exposure in the range of fractions of a microgram. A microgram is one millionth of a gram. The EPA's reference dose for lead in drinking water is set at zero parts per billion precisely because lead has no biological role in the body, but the operative word in the matcha conversation is proportion. Modern analytical instruments can detect substances at parts-per-billion and even parts-per-trillion levels. Detecting a substance is not the same as demonstrating a meaningful health risk. Toxicology depends on dose, not simply detection.
Properly sourced, third-party-tested matcha may typically result in non-detect or exceptionally trace amounts of heavy metals that are below or comply with applicable food safety standards.
Why Origin Is the Most Important Variable
Contaminant profiles also vary by growing region. Studies have found meaningful differences in heavy metal concentrations depending on where tea is cultivated. All of Japan's matcha-producing regions, including Uji in Kyoto Prefecture, Yame in Fukuoka Prefecture, and Shizuoka, are subject to Japan's national food safety system. The Ministry of Health, Labour and Welfare oversees food safety standards and monitors contaminants in the food supply, helping ensure that foods sold domestically meet established safety requirements.
Lower-grade matcha, particularly commodity-priced products with undisclosed or unverified origins, carries a meaningfully different risk profile simply because you cannot ascertain the conditions it was grown in. Contaminated farmland is at a greater risk of producing contaminated leaves.
What Regulatory Standards Say About Heavy Metals
The European Union's Commission Regulation 2023/915 sets enforceable maximum levels for lead, arsenic, cadmium, and mercury across food categories. For most plant-based foods, regulatory limits range from 0.1 to 3 milligrams per kilogram.
Heavy metal concentrations vary among matcha products, but studies of commercially available green teas and matcha have generally found lead concentrations well below established regulatory limits. Choosing matcha from reputable producers that provide recent third-party laboratory testing offers the greatest assurance of product quality.
What Sourcing Integrity Looks Like in Practice
Mizuba has spent over thirteen years building direct relationships with small, family-owned farms in Uji, Yame, and Shizuoka. These are among the most carefully stewarded growing regions in Japanese tea production, with centuries of agricultural knowledge embedded in their cultivation and harvesting practices. Our tencha comes from heritage farms, harvested at the spring flush, from plants shade-grown under traditional conditions. The provenance of each lot is traceable back to the field it came from, and the farmers and chashi who produced it are people we’ve had longstanding friendships with.
Our level of specificity is what makes the conversation about heavy metals answerable rather than abstract. Mizuba matcha is not a commodity product assembled from multiple undisclosed sources. Our teas come from particular soil (terroir!), tended by particular farmers, in regions with a documented record of careful, regulated agricultural practice. In fact, we’re proud to say for over 13 years our producers across Japan regularly test for metals and our teas always receive a clean result. Our producers routinely test their teas as part of Japan's food safety framework before export, and we maintain complete lot traceability from farm to finished package.
Heavy metals are not unique to matcha. Metals in foods (like chocolate, beer, etc!) are part of a broader conversation about agriculture and the environment. The evidence overwhelmingly shows that properly sourced, well-tested Japanese matcha continues to be a safe beverage to enjoy daily (as it has for thousands of years). The best answer to the concern is not reassurance in general terms. It is knowing exactly where your tea comes from and being able to trace it back.
Explore our single-origin ceremonial matcha, including our Yama, our current favorite!
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