Dangers of Nitrosamines. 2009
The UK Department of
Trade and Industry (now the Department of Business, Enterprise and
Regulatory Reform) characterizes nitrosamines as more toxic in more
animal species than any other category of chemical carcinogen (i).
Nitrosamines are common in cosmetics, but because they are impurities,
they are not listed on product labels.
Products That May Contain Nitrosamines
Nitrosamines are a potential impurity in 53 ingredients and more than
10,000 of the products listed in the Environmental Working Group's
database as of July 2009. Due to the common nature of this impurity,
nearly every kind of personal care product, including mascara, concealer,
conditioner, baby shampoo, pain relief salve and sunless tanning lotion,
can contain nitrosamines as an impurity. Nitrosamines have been banned
from use in cosmetics by Canada and the European Union (ii).
Where It Comes From
Nitrosamines are created in cosmetics when nitrates and various amino
acids (the building blocks of proteins) are in favorable conditions to
combine. Specifically, nitrosamines form when certain proteins, such as
diethanolamine (DEA) or triethanolamine (TEA), are used in the same
products as preservatives that can break down into nitrates. As these
various compounds break down over time, they can recombine into
nitrosamines. Both DEA and TEA are common additives used to adjust the
pH or act as wetting agents (iii). The inadvertent creation of this
carcinogenic compound can add a whole new challenge for consumers
reading labels for safety, since nitrosamines do not appear on a label,
and the precursor building blocks are not clearly noted.
Numerous studies and databases link nitrosamines to cancer. They are
listed as possible human carcinogens by the U.S. Environmental
Protection Agency, the International Agency for Research on Cancer, the
U.S. National Toxicology Program Report on Carcinogens and the
California EPA Proposition 65 list of chemicals known to cause cancer or
birth defects. Several other databases cite strong to moderate evidence
regarding the cancer-causing properties of nitrosamines. In addition,
there is some evidence of endocrine disruption at very low doses.
Studies have also linked nitrosamines to developmental or reproductive
toxicity, immunotoxicity, neurotoxicity and systemic toxicity.
The FDA began watching personal care products for nitrosamines in 1979,
and published a report stating that products containing nitrosamines
could be seen as adulterated and subject to FDA enforcement. This led to
a striking drop (from 150 ppm to 3 ppm) in concentrations of one form of
nitrosamine – n-nitrosoethanolmaine (NDELA) – in testing 12 years later
(iv). NDELA accumulates in the liver, bladder and other organs and leads
to chronic toxic health effects. It is readily absorbed through the skin
In 1996, the FDA encouraged cosmetic manufacturers to voluntarily remove
ingredients that could combine to form NDELA and to conduct testing to
understand why cosmetics become contaminated with NDELA. Despite these
encouragements, the Environmental Working Group found that one in every
10 products contains ingredient that can combine with others to form
nitrosamines. A 1998 study by the UK Department of Trade and Industry
showed that nitrosamine levels in some products actually increase in the
months after a product is opened (vi).
i Department of Trade and Industry, UK (DTI) (1998). A
survey of cosmetic and certain other skin-contact products for
ii Environmental Working Group. Skin Deep. Nitrosamines. Available
Accessed July 28, 2008.
iii Malkan, S (2007). Not Just a Pretty Face: The Ugly Side of the
Beauty Industry, pp. 58. Gabriola, BC, Canada: New Society Publishers.
iv Environmental Working Group (2007). Impurities of Concern in Personal
Care Products. Available online: www.cosmeticsdatabase.com/research/impurities.php.
Accessed July 28, 2008.
v Matyaska MT, Pesek JJ, Yang L (2000). Screening method for determining
the presence of N-nitrosadiethanolamine in cosmetics by opn-tubular
capillary electrochromatography. Journal of Chromatography A. 887:
vi Department of Trade and Industry, UK (DTI) (1998). A survey of
cosmetic and certain other skin-contact products for n-nitrosamines.