Cosmetic ingredients with an identical ingredient name may differ in quality depending on the ingredient manufacturer. Such differences can be attributed to the difference in the purification process. Even minute amounts of impurities may result in major differences in safety and quality.
Impurities in an ingredient, depending on the type, may affect health by causing irritation and/or cutaneous allergies. Impurities may also deteriorate quality. For instance, high levels of impurities may lead to discoloration or deterioration of smell after many hours of exposure to high temperatures or sunlight.
All ingredients selected by Shiseido undergo careful screening. When necessary, we evaluate purification processes and make a final validation check to make sure there are no safety concerns, including those related to impurities.
Sometimes, there is a misperception that chemically synthesized ingredients are not gentle to the skin. In fact, synthetic ingredients have undergone purification processes and are supplied relatively free of impurities; they often show a single-peak pattern in GC or HPLC analysis. In contrast, ingredients derived from natural sources, by nature, generally show multiple-peak pattern on analysis even after undergoing purification. This characteristic of natural ingredients can be advantageous but can also carry a risk because of impurities.
At Shiseido, we make final checks on the safety of both types of ingredients. Only ingredients that have demonstrated no safety concerns are formulated into products.
At Shiseido, ingredients suspected of containing impurities that may affect safety or quality undergo processes such as purification to remove the impurities; only ingredients that have demonstrated safety are used.
There are, however, some impurities that cannot be completely removed. Heavy metals in naturally derived ingredients are one type of such impurities. Lead, mercury, arsenic, cadmium and other heavy metals are known to adversely affect human health when ingested in large quantities. However, they are widely present in the environment such as soil, atmosphere and water. Sometimes, food and drinking water also contain a small amount of heavy metals. Similarly, some cosmetic ingredients are naturally derived, and products formulated with such ingredients may contain a minute amount of heavy metals. At Shiseido, we ascertain the levels of the minute amount of heavy metals contained in an ingredient and set our own internal standard to make sure that they are at safe levels before using the ingredient.
Shiseido uses only ingredients that have undergone such careful selection. We conduct additional tests such as in-use tests and dermatologist-supervised patch tests to ensure that products formulated with such an ingredient are problem-free. Thus, we are confident of the safety of all Shiseido products on the market.