Yes. Like many earth-derived materials, calcium montmorillonite bentonite clay can naturally contain trace amounts of elements such as lead and arsenic.
What matters most is not simply whether trace elements are present, but how much is actually available to the body. Available research shows that in natural montmorillonite clay, these trace metals are largely bound within the clay’s mineral structure and have very low bioavailability.
Think of these metals as locked within the clay’s structure, rather than freely available.
Why we’re comfortable using this clay
1) Studies show very low bioavailability
A 2020 study published in Scientific Reports evaluated heavy metals in mineral clay products using simulated digestion and intestinal permeability testing. The researchers found very low to non-detectable permeability for arsenic, cadmium, and lead, and concluded that the heavy metal exposure associated with these mineral clay-based products did not pose a potential hazard to consumers in that assessment.
In plain terms: trace metals may be present, but the amount available for absorption appears to be extremely low.
2) Montmorillonite clay has a strong ability to bind metals
Montmorillonite clay has a naturally occurring negative charge and high cation-exchange capacity. This gives it a strong ability to bind positively charged substances, including certain metals.
We use an unprocessed form of calcium montmorillonite clay, meaning the clay’s natural mineral structure remains intact and has not been altered in a way that would disrupt its ability to bind positively charged substances.
This binding behavior is fundamental to how this clay interacts with its environment and is one reason the metals present in the clay are not freely available in the same way they would be in other forms.
3) This clay has a long history of traditional use
Calcium montmorillonite clay—often referred to as “living clay”—has been used for generations in various cultures for personal care and wellness practices.
While traditional use alone is not scientific proof, it provides helpful context. The consistency of use over time, combined with modern research showing low bioavailability of associated metals, helps explain why this material continues to be used safely today.
Bottom line
Yes, natural clay can contain trace amounts of naturally occurring heavy metals. The important point is that these metals are largely bound within the clay’s structure and have very low bioavailability based on available research.
Combined with its well-understood mineral properties and long history of use, we believe there is no meaningful exposure concern from normal use of our Living Clay or Mineral Toothpowder as directed.
Sources & Further Learning
We’ve included a small selection of studies and resources below for those who want to better understand how natural clays work and why they’ve been used for so long.
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In-vitro bioaccessibility and bioavailability of heavy metals in mineral clay complex used in natural health products (Scientific Reports, 2020)
https://www.nature.com/articles/s41598-020-65449-4 -
FDA Amended Safety Assessment by the Expert Panel for Cosmetic Safety for MOCRA (The Modernization of Cosmetics Regulation Act of 2022) regarding - Naturally Sourced Clays as Used in Cosmetics (Cosmetic Ingredient Review, March 2023). https://cir-reports.cir-safety.org/view-attachment/?id=d5fd5bfa-685d-6aab-94d5-67acbc8713fb
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Bentonite Clay as a Natural Remedy: A Brief Review (PubMed / NIH)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5632318/ -
Supplementation of Montmorillonite Reduces Lead Toxicity in Animal Models
https://link.springer.com/article/10.1007/s12011-008-8173-0 -
Montmorillonite Alleviates Lead Toxicity in Aquatic Models (Tilapia Study)
https://pubmed.ncbi.nlm.nih.gov/25765241/ - Basics of Clay Minerals and Their Characteristic Properties (Book Clay and Clay Minerals, Chapter Excerpt June 2021) https://www.intechopen.com/chapters/76780
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Overview of Montmorillonite Properties (Cation Exchange Capacity and Adsorption Behavior)
https://www.sciencedirect.com/topics/earth-and-planetary-sciences/montmorillonite
