As a skin protectant, sunscreen is expected to wear many hats (and you should be as well when exposed to direct sunlight): We need a product that is not harmful to ingest or inhale, that does not irritate the surface of the skin, that is not harmful when it penetrates the skin, and that has lasting power over several hours and through several applications. Sunscreen is a full-time bodyguard – but how well does it hold up under the piercing lights of a background check?
Sunscreens contain one of two types of ingredients that work to protect skin from ultraviolet ray exposure and damage: chemical filters or mineral filters. But when you are buying sunscreen, read all the ingredients carefully – some will contain both chemical and mineral components. Before you slather up, look down; here’s what you need to know:
Chemical-based sunscreens are made with synthetic ingredients that penetrate the skin to absorb and filter UV rays. This means that sunscreens with chemical bases get to work once harmful UV rays have already entered under your skin, instead of blocking radiation at the surface level. The problem with most chemical ingredients is that once they have been absorbed in your body, they can become just as harmful as UV rays.
Oxybenzone and octinoxate are two commonly found ingredients that pose high toxicity risks. Both chemicals infiltrate the skin and have been found in mothers’ breast milk during laboratory studies. Once inside the body, oxybenzone and octinoxate exhibit hormone-like function and can disrupt normal hormone functioning related to the thyroid, reproductive system, and behaviors. Oxybenzone is a particularly dangerous chemical that has been found in nearly all Americans; it acts like a synthetic estrogen and is associated with endometriosis in women.
Many chemical ingredients with moderate or lower toxicity risks pose health concerns as well: homosalate, octisalate, and octocrylene have all been found to penetrate the skin, and homosalate has been linked to hormone disruption. Of the chemical filters avobenzone offers the best UVA protection, but while it will not affect your hormones, it can cause an allergic skin reaction.
Mineral-based sunscreens – or sunblocks, as they are more accurately called – are made with minerals that lay on the skin and block UV rays from entering. The two most common ingredients are zinc oxide and titanium oxide, which both have lower toxicity concerns than many chemical filters. Mineral filters are less likely to penetrate the skin than their chemical counterparts, and zinc oxide in particular offers excellent protection from UVA rays without the risk of hormone disruption or skin irritation. Of course, even these ingredients are not completely safe – both zinc oxide and titanium oxide can be harmful if inhaled. As a general rule, stick with rub-on sunscreens instead of sprays, to reduce inhalation risks.
While active chemical and/or mineral filters are the most important components in sunscreen, keep an eye out for other damaging ingredients that may try to slip past your skin unseen:
- Avoid sunscreens with Vitamin A, which typically contains the ingredients retinol or retinyl palmitate. While research is still ongoing, studies suggest Vitamin A could cause tumors or lesions to grow faster when applied to the skin in direct sunlight.
- Beware of methylisothiazolinone, a common preservative mixed into sunscreens. Methylisothiazolinone is classified as a skin sensitizer or allergen, and can cause you to have an allergic skin reaction.
None of this is meant to discourage you from wearing sunscreen – in this case, skin protection outweighs the possible risks. But make sure you are doubling up on fortifications when you are out and about: Use a sunscreen that has broad spectrum protection, wear hats, sunglasses, and clothes that cover your skin, and limit time spent outdoors when the sun is at its peak hours. And if you notice an unusual mole or growth while you’re spreading on the sunscreen, contact us here at Florida Dermatology & Skin Cancer Centers and make an appointment for a skin cancer examination.