The FDA must also look closely at the so-called inactive ingredients in sunscreens. These typically make up 50 to 70 percent of a sunscreen.
It is important to pay attention to the inactive ingredients in sunscreen as well because they often make up more of the sunscreen than active ingredients do. For example, the preservative methylisothiazolinone is of particular concern to health.
Methylisothiazolinone can be used alone or mixed with methylchloroisothiazolinone. The American Contact Dermatitis Society named methylisothiazolinone its “allergen of the year” in 2013. In March 2015, the European Scientific Committee on Consumer Safety concluded that no concentration of the chemical could be considered safe in leave-on cosmetic products; however, it is still allowed in the U.S.
Retinyl palmitate, a vitamin A derivative, is one you want to look out for, as it can promote tumor growth on skin when exposed to the sun, according to government studies. It also goes by the names of retinyl acetate and retinyl linoleate. (Retinol, or whole molecule vitamin A, on the other hand, has beneficial anti-aging properties and may help prevent cancer but should be used at night or with very limited sun exposure.)
In August 2005, scientists from the University of Rochester reported that prenatal exposure to phthalates which are chemicals found in personal care products and other consumer products that could cause the reproductive organs of male infants to develop abnormally (Swan 2005).
Some suppliers refer to dimethicones as "naturally derived from sand". Sand is no doubt the starting material for making all these silicone derivatives and what could be more "natural" than sand? But sand/quartz is the end of "natural" for silicone. The rest is attaching petrochemical based functional ingredients to the siloxane backbone to create all these -cones we can find on the label of almost every single mainstream personal care product. There are even silicone derivatives where they attach the dimethicone to a "natural" ingredient such as beeswax or plant oils.
Apart from the fact that there are petrochemicals involved in manufacturing dimethicones, even if they are attached to plant oils, they are bioaccumulative and build-up in the environment. Even though the pro-silicone front is persistently claiming silicones do not bioaccumulate and would biodegrade after how many million years?