Health Canada’s quality guide gives elemental impurity tolerance limits for natural health products. Oral product limits are expressed as daily exposure per day or body weight, while topical products have concentration limits in ppm. Only the topical concentration limits are loaded into the regulatory limits register because the oral dose limits are not direct product concentration ceilings.
Key numbers
The guide is Version 3.1, dated May 1, 2015. Section 3.2.2 and Table 2 (PDF p.17) give acceptable heavy-metal limits for topical products: arsenic 3 ppm, cadmium 3 ppm, lead 10 ppm, total mercury 1 ppm and antimony 5 ppm. It adds that licence holders must ensure the finished product contains “as little heavy metal contamination as possible”. The Diaper Rash Products Monograph (2024) routes the finished-product specifications of zinc oxide diaper-rash natural health products to this guide, so these are the operative Canadian topical limits for that product class.
Table 1 (oral, adult per day and per kg body weight per day): total arsenic < 10.0 µg/day or < 0.14 µg/kg b.w./day; inorganic arsenic < 2.1 µg/day or < 0.03 µg/kg b.w./day; organic arsenic < 1.4 mg/day or < 20 µg/kg b.w./day; cadmium < 6.0 µg/day or < 0.09 µg/kg b.w./day; lead < 10.0 µg/day or < 0.14 µg/kg b.w./day; total mercury < 20.0 µg/day or < 0.29 µg/kg b.w./day; methylmercury < 2.0 µg/day or < 0.029 µg/kg b.w./day. Methylmercury testing is not needed when total mercury is below the methylmercury limit. Section 3.2.1.2 sets a chromium VI tolerance of 0.29 µg/kg b.w./day where contamination is a concern. A total heavy metals result of not more than 10 ppm is acceptable only under stated conditions.
The appendix specification table (PDF p. 34) prints the chromium row as “Chromium IV (if applicable)“. It carries the same oral limit as the chromium VI section and, in one table, “Topical: 5 ppm”. The heading and identical oral limit identify the row as hexavalent chromium. Table 2 in the body has no chromium row and §3.2.1.2 names chromium VI, so the topical chromium entry and its species label are internally inconsistent. The topical 5 ppm appears only in that appendix row and is not used as a limit.
Finished-product testing is not required where raw materials were tested or meet a pharmacopoeial grade (§3.2.1, PDF p. 15). The Primary Sunscreen Monograph requires sunscreen finished-product specifications to follow this guide, which is how these topical limits apply to titanium dioxide and zinc oxide sunscreens licensed as natural health products in Canada. See Primary Sunscreen Monograph.
The figures above are read from a web copy of this guide printed from canada.ca on 2026-09-25 (SHA-256 12cb2d9cbfaeeb918df69e0217e2fc9ce760be804c1943fd5e7635421c3425c3). That copy prints Version 3.1, dated May 1, 2015.
Scope
For diaper-rash products, the Diaper Rash Products Monograph (see Diaper Rash Products Monograph) sends products made only with natural health product ingredients, such as corn starch or kaolin powders and zinc oxide pastes, to this guide for finished-product specifications. Mineral-oil and petrolatum products are non-prescription drugs and are not covered by it.
The methylmercury value in this guide is an oral daily tolerance only. Where the guide is routed to topical product rows (corn-starch baby powder and the two diaper cream rows), it is for the topical total-metal limits in Table 2; it does not supply a methylmercury limit or a methylmercury measurement for those rows.
Update history
No substantive edit history is available in this build. The full commit record is available in git.