We already know some makeup companies can’t be trusted with their advertisements, so why should we trust them with what they’re using in their products? To be clear, cosmetics have come a long way since the ancient Egyptians started using a ground-up mineral substance containing lead and sulphide for eyeliner, but most skin care experts agree we should still err on the side of caution when it comes to our health.

Depending on the company, there could be any number of toxic ingredients within the products capable of damaging our eyesight, endocrine system, or nervous system. Parabens are preservatives commonly found in cosmetics that prevent the growth of bacteria, for example. They’ve also been known to disrupt the body’s production of estrogen, and have been found in high concentrations in human breast tumors.

The chemicals found in cosmetics can be even more dangerous for pregnant women. Researchers from SUNY Downstate Medical Center’s School of Public Health recently discovered compounds in makeup that can impact the health of a mother and her newborn. Specifically, they found that the organic compound butylparaben can disrupt the endocrine system, causing problems with fertility and the immune system, while the antimicrobial compound triclocarban can lead to premature birth and decreased body length.

Everything becomes more dubious when we consider all the fake products with unknown ingredients that are available to consumers. In November 2013, the Department of Homeland Security conducted a thorough investigation into counterfeit makeup manufacturing rings, and discovered products like lipstick and eyeliner with dangerously high concentrations of metal and carcinogenic ingredients. These were often sold as the popular brand name MAC on websites like Amazon.

Before purchasing any cosmetic product and applying it to your body, check the Environmental Working Group’s Skin Deep database for all known chemicals. It also has tips for practicing safe skin care.