This study on cosmetics investigated the relationship between synthetic ingredients and skin health. Published in 2018, it was the first of its kind:

“The more synthetic ingredients contained in a product, the less of a positive effect on average biodiversity it appeared to have, especially within the first two weeks.”

“The (skin microbiome) diversity was lowered further still on Western subjects with skin ailments [10,38,50,54–56]. Acne was found to be a Western skin ailment, absent on skin from individuals in rural Papua New Guinea and Paraguay [57]. This is further evidence that an environmental factor in the Western world is causing a catastrophic ecosystem collapse on the skin.”

This study found that North American cosmetic products contain high levels of fluorinated compounds. Only 8% of the 231 cosmetics screened for total fluorine had any PFAS listed as ingredients, and only 3% of the 29 cosmetics in which targeted PFAS were measured had any PFAS listed as ingredients.

This database is an excellent resource. You can search for cosmetic products, discover their ingredients and learn more about cosmetics safety. EWG assigns safety ratings to products and more.