A nitrosamine is an organic substance formed by a specific reaction of two nitrogen containing substances one of which is an amine (such as a protein for example). The second nitrogen containing material is called a nitrosating agent such as nitrites used as food preservatives (particularly in lunch meats).
Nitrosating agents, amines and nitrosamines are common natural compounds found in many different settings and situations. For example, Nitrosamines may be found in many food products including beer, fish, fish byproducts, and in meat and cheese products preserved with nitrites (the U.S. government has established limits on nitrite content of food). In addition to foods preserved with nitrites, some foods such as spinach contain nitrates, another nitorsating agent. Nitrosamines also form in the digestive tract from normal food, by normal metabolic processes in the body and in tobacco smoking. Nitrosamines are widespread in the environment though generally at extremely low levels (order of magnitude: 1 part-per-billion [ppb]). Sources of nitrite include natural occurrence in water usually via microbial reduction of nitrate or malfunctioning of mixed-bed, resin water purifiers.
Nitromsamines may be formed in cosmetic and personal care products only if they contain an ingredient which acts as a Nitrosating agent and an amine, and they are together under conditions that favor Nitrosamine formation (generally acidic conditions). The Nitrosation may occur during manufacture or during product storage.
Many Nitrosamines have been found to be carcinogens when tested at high levels in animals, and the FDA has recognized that Nitrosamines have been shown to be capable of penetrating the skin. The ones that cause cancer are well known and steps are taken to minimize their occurrence in cosmetics and personal care products. However, most products do not contain any nitrosamines and when they do occur, the levels are typically very low and do not present any health risk to consumers. Cosmetic and personal care products are formulated to eliminate or reduce the formation of nitrosamines.
What about Nitrosamines and Cosmetics? Nitrosamine contamination of cosmetics was first discovered in early 1977. The presence of Nitrosamines was not known before their discovery in 1977. At that time, a study of cosmetic creams and lotions found the presence of N-Nitrosodiethanolamine (NDELA). The FDA addressed the issue of the contamination of cosmetics with Nitrosamines in a notice published in the Federal Register of April 10, 1979 (44 FR 21365). The FDA has monitored the presence of Nitrosamines in cosmetics over the intervening years and periodically published the results of product surveys. In 1979, the FDA published a regulatory notice stating that cosmetics containing Nitrosamines may be considered adulterated and subject to enforcement action. The FDA has never determined that the very low levels of Nitrosamines found in personal care products represent a public health risk nor has the agency found it necessary to take regulatory action against products. Even today, the FDA continues to monitor the contamination of cosmetics with Nitrosamines. To help better understand and control the presence of Nitrosamines in cosmetics, the cosmetic industry has worked closely with the Food and Drug Administration to conduct research about how they are formed and how to avoid their presence in products. This research has led to a clear understanding about the conditions under which Nitrosamines are formed and the ability to carefully avoid or control their presence in cosmetics. The levels of Nitrosamines that might be found in cosmetics is very low and the available scientific evidence does not indicate that they are a threat to human health. The most potent carcinogens among the nitrosamines and their secondary amine precursors are well known. In addition, since their discovery in 1977, the scientific knowledge of how Nitrosamines are formed and how their formation is prevented has significantly advanced. To ensure that nitrosamine levels are kept as low as possible, the cosmetic industry applies the following approach: • Elimination of adventitious sources of nitrite and nitrogen oxides, • Elimination and reduction of secondary amine contaminants, • Use of raw materials that are free of nitrosamine contamination, • Incorporation of an inhibitor of nitrosamine formation to the product formulation may be an additional precaution. In addition, there are available very sensitive analytical methods that can be applied in monitoring the effectiveness of these steps and to ensure that Nitrosamines are not formed during manufacture or after storage of the product. There is a large amount of information available concerning Nitrosamine formation in Foods and other FDA regulated products. A few key references are provided for your information.