Bentonite clay contains trace amounts of naturally occurring elements like lead and aluminum, but scientific evidence shows that these elements are tightly bound in stable mineral forms and not absorbed by the body.
If you look at the Redmond Clay elemental analysis, you might find it a little surprising. It lists elements like aluminum, cadmium, and lead—substances we typically think of as toxic. So why would anyone want to use clay on their skin or in products for people? Is it actually safe?
To understand how Redmond Clay can contain trace elements and still be safe, it helps to take a closer look at the science behind natural minerals. Let’s break it down.
Clay Comes From the Earth—So It Contains Naturally Occurring Elements
Bentonite clay—also known as montmorillonite clay—forms from ancient volcanic ash that has weathered over time. Because it’s 100% natural and sourced straight from the earth, it contains many of the same elements found in the earth’s crust. That includes beneficial minerals like calcium and magnesium, as well as trace amounts of metals like aluminum and lead.
This isn’t unusual. Nearly all natural substances—carrots, spinach, salt, and more—contain trace levels of heavy metals simply because they come from the earth. According to the EPA, even clean, uncontaminated soil can contain 50–400 parts per million (ppm) of lead. In comparison, natural clays like Redmond Clay typically contain just 12–20 ppm—well within, and often lower than, what’s commonly found in soil.
What Matters Is the Form of the Element
Just because aluminum is listed on an elemental analysis of clay, it doesn’t mean it’s floating around freely as pure metal. It’s kind of like seeing “hydrogen” and “oxygen” on a report about water. Yes, those elements are there, but they’re chemically bonded to form H₂O, not floating around as flammable gases.
In clay, aluminum is tightly bound to oxygen and silica in a stable compound called aluminum silicate. This is completely different from isolated, pure aluminum—the form linked to health concerns. To separate those elements and create free aluminum, you’d need extreme heat, high pressure, and complex chemical processes. None of those happen in the human body. So the aluminum stays locked in its natural mineral form and remains unchanged when used externally or ingested in small amounts.
In 1977, the FDA funded a study that concluded bentonite clay is not absorbed by the body and causes no harm in animals, even at very high dietary levels. Here’s what the study says:
“Apparently, very little, if any, bentonite is absorbed after oral administration and as much as 3 percent in the diet has no observable adverse effects on experimental animals. No adverse effects have been observed at dietary levels as high as 12 percent in experimental animals. The human therapeutic dose for diarrhea is about 250 to 1,000 mg per kg.”
Clay Has a Natural "Magnet" for Metals
Here’s where it gets really fascinating.
Clay particles—especially those from the smectite family (like Redmond’s or other bentonite clays) carry a strong negative charge. This is due to a property called Cation Exchange Capacity (CEC). In simple terms, it means the clay can attract and bind positively charged particles, including heavy metals such as lead, cadmium, and mercury.
Think of it like a fridge magnet. The magnet itself is made of metal, yet it still attracts other metal objects. Similarly, clay may contain trace metals, but its structure and charge allow it to pull in and hold onto other positively charged particles, including unwanted toxins.
Because of this, clay is often used as a natural chelator—a substance that helps bind and remove toxins—in both animal and human studies.
Animal Studies Show Clay Helps Remove Metals—Not Add Them
What gives us real confidence in the safety of clay is the science behind it.
In several studies, animals that were fed clay actually showed reduced levels of heavy metals in their bodies. For example, in a study on pigs:
“[Clay] was found to significantly reduce lead concentration in tissues, including blood, brain, liver, bone, kidney, and hair.”
This is the magnet effect of CEC in action.
Here are just a few studies that show how clay helps bind and remove heavy metals:
Human Safety Studies Also Look Promising
Animal studies are helpful—but what about people?
Fortunately, several human studies have explored the safety of clay consumption. One clinical study concluded:
“No significant differences were shown in hematology, liver and kidney function, electrolytes, vitamins A and E, and minerals in either group… These results demonstrate the relative safety of [bentonite] clay in human subjects and will serve as a basis for long-term human trials.”
Source: PubMed Study
In other words, clay is shown to be safe for short-term human use, with no adverse effects on key health markers.
How Much Lead Is Actually in Clay Products?
Now that we’ve covered the science behind elemental analysis and Cation Exchange Capacity, you may be wondering: How much lead is actually present in the products I use?
Let’s break it down using a common measurement—parts per million (ppm)—and convert it into something more tangible—micrograms (mcg) per serving.
How to Convert PPM to Micrograms
To estimate the micrograms of an element (like lead) in a given amount of clay, follow this basic formula:
- Elemental ppm ÷ 1,000,000 = % of that element
- % of element × total product weight (in grams) = grams of the element
- Grams of element × 1,000,000 = micrograms (mcg)
Example 1: A Teaspoon of Clay Powder
- Weight of clay: 2.75 grams
- Lead concentration: 12 ppm
Calculation:
12 ÷ 1,000,000 = 0.000012
0.000012 × 2.75 g = 0.000033 g
0.000033 g × 1,000,000 = 33 mcg of lead
Example 2: 1 Gram of Clay Toothpaste
Let’s assume clay makes up 22% of the toothpaste formula.
- Weight of clay: 0.22 g
- Lead concentration: 12 ppm
Calculation:
12 ÷ 1,000,000 = 0.000012
0.000012 × 0.22 g = 0.00000264 g
0.00000264 g × 1,000,000 = 2.64 mcg of lead
How Does This Compare to Everyday Foods and Water?
For context, here’s how much lead can be found in common natural sources, according to FDA and EPA data:
- Sweet potatoes (FDA Total Diet Study 2018–2020):
~21 ppb lead → ~4.76 mcg in an 8-oz serving - Drinking water (EPA limit: 15 ppb lead):
~3.4 mcg per 8-oz glass → ~27.2 mcg per day if drinking the recommended 8 glasses
What’s The Story On That Prop 65 Warning for California Residents?
As for the California Prop 65 warning you may see on natural products, including clay and clay-based products, it doesn’t necessarily mean the products are unsafe. California law requires this label on any product containing certain naturally occurring elements—even if they’re also in carrots, spinach, or sweet potatoes. Learn more here.
Take Home Message
Yes, natural clay contains elements like aluminum and lead, but when it comes to clay, form and function matter.
The results of the elemental analysis might seem surprising at first glance, but it doesn’t tell the whole story. Once you understand the form (how these elements are bound in stable compounds) and function (how clay interacts with the body), it becomes clear why natural clays like Redmond Clay have been safely used for generations.