These active ingredients are the components that keep your skin from burning in the sun for a period of time. The problem with these active ingredients is that when exposed to sun, they break down and create free-radicals on the skin. Free radicals can cause cancer. So, even if you're not being visibly burned, your skin can get damaged invisibly from these chemicals. How does this happen? Instead of being a sunblock that reflects the sun's rays, these particles absorb the sun's energy. The energy has to be released from the particle somehow, so it breaks down and creates free-radicals
Active ingredient toxicity:
The following active ingredients in chemical sunscreens have been found in mother's milk (indicating it penetrates the skin and into the bloodstream) and are known hormone disruptors:
1) Oxybenzone also produces excess reactive oxygen species that can interfere with cellular signaling, cause cell mutations and lead to cell death.
2) Octinoxate (Octylmethoxycinnamate) also produces damaging reactive oxygen species upon exposure to sunlight.
4) PABA (Octyl Dimethy PABA, PABA Ester) has a long list of concerns. In the manufacturing process, it can be contaminated with nitrosamines, a group of dangerous carcinogenic chemicals. It too produces free radicals on the skin, and lab tests have shown it to cause cellular mutations. PABA has long been an ingredient to be avoided.
The following two active ingredients, whilst are not proven hormone disruptors penetrate the skin and have been found in mother's milk
2) Octocrylene. Octocrylene is restricted in Japan because it creates free radicals on the skin when exposed to sunlight and is a penetration enhancer. One study says that "when octocrylene penetrates into the skin, the level of reactive oxygen species increases above that produced naturally under UV illumination." Another free-radical-forming chemical.
Avobenzone and Mexoryl SX are two active ingredients with very limited skin penetration and no evidence of hormone disruption.
However, avobenzone alone may break down when exposed to sunlight and must be stabilized with other chemicals such as octocrylene.
Laboratory studies of several sunscreen chemicals indicate that they may mimic hormones and disrupt the hormone system (Krause 2012, Schlumpf 2001, 2004, 2008). Some research on animals suggests that oxybenzone and other sunscreen chemicals can be toxic to reproductive systems or interfere with normal development. Another sunscreen chemical, 4-methylbenzidyl camphor, used in Europe and under petition for use in the U.S. is a hormone disruptor.
Two European studies have detected sunscreen chemicals in mothers’ milk, indicating that the developing fetus and newborns may be exposed to these substances (Schlumpf 2008, Schlumpf 2010). A 2010 study by Margaret Schlumpf of the University of Zurich found at least one sunscreen chemical in 85 percent of milk samples.
The most problematic of the sunscreen chemicals used in the U.S. is oxybenzone, found in nearly every chemical sunscreen. EWG recommends that consumers avoid this chemical because it can penetrate the skin, cause allergic skin reactions and may disrupt hormones (Calafat 2008, Rodriguez 2006, Krause 2012). Preliminary investigations of human populations suggest a link between higher concentrations of oxybenzone and its metabolites in the body and increased risk of endometriosis and lower birthweight in daughters (Kunisue 2012, Wolff 2008).
The federal Centers for Disease Control and Prevention has detected oxybenzone in more than 96 percent of the American population, based on a representative sampling of more than 2,500 children and adults (Calafat 2008). Researchers found higher concentrations of oxybenzone in samples collected from participants during the summer months and concluded that sunscreen use may explain this seasonal difference.
FDA must also take a close look at the so-called “inactive ingredients” in sunscreens. These typically make up half to nearly all of a sunscreen product.
One ingredient in particular is a cause for concern: methylisothiazolinone, or MI, a preservative. This year, EWG has found MI listed on the labels of 91 sunscreens, 13 marketed for children and 54 SPF-rated daily moisturizers. MI is used alone or in mixtures with a related chemical preservative called methylchloroisothiazolinone, or MCI.
in 2013 Laboratory studies indicate that MI is a skin sensitizer or allergen. Over the past several years, physicians have reported serious cases of serious skin allergy, most notably in children exposed to MI from baby wipes and other products meant to be left on the skin (Chang 2014). In a study published last year, researchers surveyed the ingredients in 152 children’s body care products labeled “hypoallergenic” and found MI in 30 of them (Schlichte 2014). One of these was a Neutrogena sunscreen marketed under the name “Pure & Free Baby” sunscreen.
In January 2015, researchers from 15 clinics in the U.S. and Canada reported an increase in MI allergy in patients. The researchers concluded that they had documented “the beginning of the epidemic of sensitivity to methyliosthiazolinones in North America.” (Warshaw 2015).
Mineral sunscreens are made with zinc oxide and titanium dioxide as active ingredients. They form a film on top of the skin that reflects or scatters UV light. Not as popular because it can create a white and pasty sheath on your skin but it offers the safest and best protection around.
It is important that non nano zinc oxide and titanium dioxide are used as nano particles can penetrate the skin.
I mix some my zinc suncreen with mineral foundation to effectively reduce the 'white' effect.
The best protection is of course to reduce exposure to the sun especially between 11am and 4pm. Cover up with a hat and protective clothing. Even if using mineral sunscreen, be sure to apply it frequently. Every hour if possible. We are not designed to have prolonged exposure to the sun. The natural reaction of our skin is to burn in the sun after a certain amount of time. This is our in-built protection from from UV rays. It's our bodies way of saying to us "Hi..you're burning and those free radicals are multiplying. Get out of the sun!!"