Heavy Metals Testing

The results

One retained sample of Essential Mint from lot 001 was submitted to an independent analytical laboratory and tested for the four elements that regulators treat as the priority set: arsenic, cadmium, mercury and lead. The analysis ran under USP General Chapter <233>, the inductively coupled plasma spectrometry procedure used to release pharmaceutical products.²

We are publishing the certificate unedited, including the laboratory's own qualifiers. The report carries the standard notes that product details are supplied by the client and are not verified by the laboratory, and that not all of the laboratory's methods hold ISO/IEC 17025:2017 accreditation. We would rather you read those lines than have us paraphrase them away.

How to read a result of "not detected"

"Not detected" is not the same claim as "zero." Every instrument has a floor. Two numbers define it, and both appear on the certificate:

• Limit of detection (LOD), 0.002935 ppm. The smallest amount the instrument can reliably distinguish from background noise. Below this, the laboratory cannot say anything is there.
• Limit of quantification (LOQ), 0.008633 ppm. The smallest amount the instrument can put an accurate number on. Between the LOD and the LOQ, a laboratory can tell that something is present but cannot say precisely how much.

So the honest reading of this panel is: arsenic and cadmium were not present above roughly three parts per billion. Mercury was detected somewhere below nine parts per billion, too little to quantify. Lead was present and measurable, at 0.02377 ppm, which is about 24 parts per billion.

Putting 0.024 ppm of lead in context

A number in isolation is not information. Here is how 0.02377 ppm sits against the standards that actually apply to a product like this one, and against the exposure thresholds toxicologists use.

Washington State: 1 ppm

A toothpaste that contains no fluoride and makes no therapeutic claims is regulated in the United States as a cosmetic rather than as an over-the-counter drug.³ Washington's Toxic-Free Cosmetics Act set the first state lead standard in the country: as of January 1, 2025, cosmetic products sold in Washington may not contain lead at or above 1 ppm.⁴ We manufacture in Seattle, so this is the binding rule for us. Our result is roughly one forty-second of that limit.

FDA guidance for cosmetics: 10 ppm

The FDA recommends a maximum of 10 ppm lead as an impurity in cosmetic lip products and externally applied cosmetics, a level the agency concluded would not pose a health risk and which more than 99 percent of the 685 products it surveyed already met.⁵ That guidance was not written with toothpaste in mind, so treat it as a reference point rather than a rule we are held to. Our result is roughly one four-hundredth of it.

Daily exposure: Proposition 65 and USP

Concentration matters less than dose. A pea-sized amount of toothpaste is about 0.25 g,⁶ so twice-daily brushing puts roughly 0.5 g of paste in the mouth per day. At 0.02377 ppm, that whole 0.5 g carries about 0.012 micrograms of lead.

California's Proposition 65 sets the maximum allowable dose level for lead, as a reproductive toxicant, at 0.5 micrograms per day.⁷ USP General Chapter <232> sets a permitted daily exposure for lead in orally administered drug products of 5 micrograms per day.⁸ The 0.012 microgram figure above is roughly 2.4 percent of the Proposition 65 level and roughly 0.24 percent of the USP level, and it assumes every last milligram of paste is swallowed rather than spat out.

That arithmetic is offered so you can check our work, not as a safety determination. It uses a single lot, a stated brushing quantity, and thresholds built for other product categories. Public health bodies including the WHO hold that no level of lead exposure is known to be without harmful effects,⁹ and we agree with the implication: the goal is not to sit comfortably under a limit, it is to keep pushing the number down.

Why there is any lead in toothpaste at all

Almost never because someone added it. Lead, arsenic, cadmium and mercury occur naturally in the earth's crust, and they travel into finished products through mineral raw materials. In oral care the usual carriers are the mineral abrasives and remineralizing agents: calcium carbonate, hydroxyapatite, bentonite and other clays, and various silicas and salts. These are mined or precipitated from mined feedstock, and unless the supplier purifies aggressively and tests each lot, whatever the deposit contained comes along.¹

This is why "natural" and "clean" claims on a carton tell you nothing about elemental purity. A mineral-heavy botanical formula can easily carry more lead than a synthetic one. The only thing that answers the question is a lot-level test with a low detection limit, published.

It also means the number is a property of the raw materials in a given lot rather than a fixed attribute of a brand. Suppliers change and deposits vary, which is the reason to keep testing rather than to test once. Our intention is to update this page as further lots are analyzed.

The other panel: water activity and microbiology

Elemental purity is one half of a contamination question. The other half is microbiological, and it is the reason most toothpastes carry a preservative system. Essential Mint is anhydrous, an oil-based paste with no added water, so we also had the same lot tested for water activity and microbial load.

Water activity is the measure that governs whether microorganisms can grow in a formulation at all. It is not the same as water content: it describes how much of the water present is free and available. USP General Chapter <1112> summarizes the thresholds. Gram-negative bacteria stop proliferating below about 0.91, gram-positive bacteria below about 0.86, most fungi below about 0.77, and even the most osmotolerant yeasts and xerophilic molds cannot grow below roughly 0.60.¹⁰

A water activity of 0.352 sits well beneath every one of those floors. That is the physical chemistry behind an unpreserved formula: there is nothing for a preservative to protect, because there is no free water for an organism to grow in.

What this page does and does not claim

• These are lot 001 results. They are evidence about that lot and reasonable evidence about our supply chain, and we plan to add later lots as they are tested. No single certificate can speak for every tube we will ever make.
• It is not a health claim. Nothing here says that our toothpaste prevents, treats or reduces any disease or condition, or that lower elemental impurities produce a clinical benefit for you.
• It is not a comparison to any named competitor. The independent 2025 testing we reference is a third party's work with its own methods and detection limits. Results from different laboratories, methods and detection floors are not directly comparable, and we have not run competitor products ourselves.
• Detection limits bound the negatives. "Not detected" means below roughly 0.003 ppm on this method. It does not mean absolutely absent.

If you want to check any of this, the certificates are linked above in full and the standards we cite are all public. If you find an error on this page, write to support@athenanaturals.us and we will correct it.