A great clarifying article written by the founder of The Organic Pharmacy, Margo Marrone:
"The debate between chemical sunscreens and mineral organic sunscreens is an important one. Physical sunscreens use physical filters such as Zinc Oxide and Titanium Dioxide whilst chemical sunscreens use chemical UV filters. The issue with chemical sunscreens is that when applied they only become effective after 30 minutes of application where as mineral ones offer immediate protection. Once chemical sunscreens come in contact with UV rays they can potentially become photo toxic and cause allergies and irritation but more importantly cause bigger problems. Some chemical UV filters have been shown to have endocrine activity, mimicking oestrogen or testosterone. And disrupting the hormone system which is very delicate in the first place. Studies show that Oxybenzone are toxic to the reproductive systems particularly because it can penetrate the skin and enter the blood stream. In addition to their problems for humans, chemical sunscreens present a problem for our environment in particular coral reefs as they stimulate a virus that kills coral and some beaches have begun to ban these chemicals on the beach.
Mineral sunscreens (Zinc Oxide and Titanium Dioxide) remain on the skins surface giving instant protection and unlike chemicals they don’t break down or become unstable because they don’t absorb the suns rays but reflect it instead. They also offer longer protection and better hydration, making them safe for all the family.”
The main chemical sunscreens of concern are: