Heavy metals in cosmetics are not usually added; they arrive with the raw materials. A red iron oxide, a clay, a mica and even a water supply all carry trace metals, and the brand that does not test is relying on a supplier’s word. The regulatory picture differs sharply between markets, and the testing strategy has to match the product type.
1. Which metals matter
Lead, arsenic, mercury and cadmium are the four that most jurisdictions regulate or restrict, and antimony, nickel and chromium are commonly tested. Nickel and chromium are relevant because they cause contact allergy at trace levels in some consumers, and they appear in pigments and in metal packaging. Mercury is prohibited as an intentional ingredient in most markets and is a contamination concern in some imported materials.
2. How metals get in
Pigments and lakes are the largest source, particularly natural earth pigments. Clays – bentonite, kaolin – carry a variable load depending on the deposit. Talc can contain trace metals and, in some deposits, asbestos, which is why talc sourcing is audited separately. Water and recycled packaging are smaller but real sources. A formula with 20 percent pigment tests very differently from a gel with 2 percent.
3. Limits by market
The EU regulates certain metals through ingredient restrictions and impurity limits, and the safety assessor is expected to justify any trace level against the toxicological threshold. The US has no federal limit for most metals in cosmetics, but some states do, and California’s rules have changed the testing practice for colour cosmetics. Canada and Japan each publish their own impurity guidance. A product sold in several markets has to meet the strictest applicable limit, not the average.
4. The test method
Inductively coupled plasma mass spectrometry is the standard method, with a digestion step that has to be validated for the matrix. A cream with a high oil load digests differently from a pressed powder, and a method validated on one matrix may recover metals poorly in another. Ask the laboratory for the method, the detection limit and the recovery data rather than a single number.
5. Frequency and batch linkage
Testing every batch is expensive and unnecessary. The practical approach is to test each raw material lot at incoming, and to test the finished product once per formula per year, or whenever a pigment supplier changes. A brand that tests the finished product every batch but never tests the raw materials is testing the sum and ignoring the parts.
6. Packaging and the migration question
Metal closures, decorative metallised film and printed inks can migrate metals into the product. A lipstick in a metal tube with a coloured lacquer is a migration scenario that a product-only test misses. Ask for a migration test on the pack where the product contacts a decorated surface directly.
7. Commercial profile
Inductively coupled plasma testing on the finished product, three to four weeks, one sample per batch family. See the cream range and the microbial testing guide for the rest of the safety programme.
