A number of metals, including lead, arsenic, mercury, aluminum, zinc, chromium and iron are found in cosmetics ranging from lipstick to whitening toothpaste, eyeliner, nail color and more.
Products That May Contain Metals
Lead may be a contaminant in over 650 products listed in Skin Deep. Lead can be found in a range of cosmetic products including sunscreens, foundation, nail colors, lipsticks and whitening toothpaste. Several ingredients derived from plant sources, such as cottonseed oils and rice derivatives, may contain heavy metals such as lead and mercury.
Titanium dioxide and zinc oxide are widely used in sunscreens, and zinc oxide is also common in foundations, concealers and diaper ointments (up to 4 percent of products in Skin Deep).
Some metals serve as colorants. For instance, chromium is used in a very small number of products as a colorant, and iron oxides are common colorants in eye shadows, blushes and concealers. Some aluminum compounds are colorants in lip glosses, lipsticks and nail polishes. In addition, some color additives may be contaminated by heavy metals, such as D&C Red 6, which can be contaminated by arsenic, lead and mercury (i).
Arsenic is a contaminant in about 641 products, or about 2.5 percent, of those listed in Skin Deep.
Zinc is used in a small number (47) but wide array of products, including moisturizers, shampoos and foundations.
Mercury has been reported in very few brands of mascara and eye drops.
Where It Comes From
These metals can occur in cosmetics as intentional ingredients or as contaminants of constituent ingredients (ii).
Metals have various properties in the body. For instance, iron is necessary for blood oxygenation. However, at higher accumulations, metal may have negative effects. Cancerous breast biopsies show higher accumulations of iron, nickel, chromium, zinc, cadmium, mercury and lead than non-cancerous biopsies, and several metals act like estrogen in the presence of some breast cancer cells (iii).
Some metals or metal compounds, such as titanium dioxide and zinc oxide, show little evidence of toxicity, according to the Environmental Working Group's Skin Deep database. However, when these ingredients are micronized into nanoparticles, they may be toxic when inhaled or absorbed the skin. Very little research has verified the safety of nanoparticles, whose physical properties change when the particles become that small (iv).
Lead, which may be an impurity in nearly 3 percent of all products in the Skin Deep database, is a proven neurotoxin – linked to learning, language and behavioral problems. It has also been linked to miscarriage, reduced fertility in both men and women, hormonal changes, menstrual irregularities and delays in puberty onset in girls. At puberty, boys' developing testes may be particularly vulnerable to lead. Pregnant women and young children are also vulnerable because lead crosses the placenta and may enter the fetal brain (v).
Concerns about lead toxicity have existed since early civilization, and some countries banned lead from paint over 100 years ago. Research during World War II showed that lead created problems at lower levels than previously thought. Nevertheless, the United States did not take concerted action until the 1970s, when lead was phased out of paint and gasoline after decades of public challenge against the lead industry (vi). It still has not been actively phased out of cosmetics (vii).
Mercury is linked to nervous system toxicity, as well as reproductive, immune and respiratory toxicity, according to the Skin Deep database. Mercury is also found in thimerosal, which is a mercury-based preservative. Mercury is particularly hazardous during fetal development, and is readily absorbed by the skin. Neither mercury nor thimerosal are highly common as direct ingredients or impurities, but the high toxicity of this metal means that the presence of mercury in any cosmetics is a concern.
Other metals show a similar tendency to be toxic. For instance, there is strong hazard-based evidence that zinc is a human immune and respiratory toxicant. In addition, one or more animal studies show tumor production at low levels, and zinc is persistent and bioaccumulative, according to Skin Deep. Aluminum-based compounds vary in their toxicity, but some are linked to neurotoxicity, developmental reproductive toxicity and cancer. Some may be derived from and tested on animals. Chromium is strongly linked to immune and respiratory toxicity, as well as systemic toxicity. Animal studies show tumor formation at low doses.
i Environmental Working Group (2007). Impurities of Concern in Personal Care Products. Available online here. Accessed November 17, 2011.
ii Environmental Working Group (2007). Impurities of Concern in Personal Care Products. Available online: www.cosmeticsdatabase.com/research/impurities/php. Accessed July 28, 2008.
iii Gray, J (2008). State of the Evidence: The Connection between Breast Cancer and the Environment. San Francisco, CA: Breast Cancer Fund.
iv Environmental Working Group. Sunscreen Report: Nanotechnology – Summary. Available online: http://www.cosmeticsdatabase.com/special/sunscreens2008/report_nanotechnology.php. Accessed July 28, 2008.
v Gray, J (2008). State of the Evidence: The Connection between Breast Cancer and the Environment. San Francisco, CA: Breast Cancer Fund.
vi The Campaign for Safe Cosmetics (2007). A Poison Kiss: The Problem of Lead in Lipstick. Available online: http://www.safecosmetics.org/docUploads/A%20Poison%20Kiss.pdf. Accessed July 28, 2008.
vii The Campaign for Safe Cosmetics (2007). A Poison Kiss: The Problem of Lead in Lipstick. Available online: http://www.safecosmetics.org/docUploads/A%20Poison%20Kiss.pdf. Accessed July 28, 2008.