If you’re anything like us, your New Year’s resolution for the past ten-or-so years has been to wear more sunscreen. But whether you wear it daily or just on particularly sunny days, what should we know about the stuff we slather and spray? And what happens when we swim in the ocean, or a lake, or a pool, or we at least eventually shower after putting it on? Regardless of the activity, that sunscreen on our skin likely gets washed into a water source or down the drain, and most likely ends up in the ocean. As it turns out, this is not so good. Even in low concentrations, chemicals found in sunscreen can harm reefs and marine life. And in high concentrations, they can have devastating effects. In this Wise Guide, we’re going to tell you everything you need to know about the ecotoxicity of your sunscreen.

What to be wise on:

Sunscreen’s harmful impacts on our oceans run deep (literally). It is estimated that 14,000 tons of sunscreen wash into the oceans each year, which is the weight of over 1,100 school buses. Horrifying, we know. Sunscreens contain a few chemicals that are particularly problematic, including oxybenzone and octinoxate, two of the most commonly used UV blockers. Researchers all over the world have determined that these two infamous chemicals are harmful to marine life, in part because they are made of nanoparticles. When these nanoparticles get washed off of our skin and into the water, they are absorbed by coral, upon which they have devastating effects. These chemicals impair the DNA of coral so that it becomes sterile and unable to reproduce. They also cause coral to trap heat. When coral reaches a certain temperature, it expels the algae that grows on it and provides it with protection and nutrients. And when the algae leaves, the coral turns white (hence “coral bleaching”), and usually dies. That’s just one devastating effect of sunscreen. 

Sunscreen has a host of other negative consequences on oceanic ecosystems. It can impair growth and photosynthesis of green algae, cause defects in young mussels, damage the immune and reproductive systems of sea urchins, decrease the fertility and damage the reproductive systems of fish, and accumulate in dolphins’ tissues and be transferred to their young. These chemicals are bad news, and you may be slathering them on your body without even knowing it. As of this writing, only one state (Hawaii) has outlawed the sale of sunscreens containing oxybenzone and octinoxate, and this law just took effect on January 1, 2021. Safe to say, we’ve got a long way to go in protecting our oceans from these nasty chemicals. Until they’re banned from sunscreen and other personal care products altogether, we must be wary of their presence. 

The factors to consider:    

Ingredients
Oxybenzone and octinoxate are the most commonly studied UV blockers, but they’re not the only sunscreen ingredients that may be harmful to marine life. There are several other chemicals that may be damaging to oceanic ecosystems when they accumulate in the water. When you’re shopping for sunscreen, we recommend avoiding any form of microplastic beads, nanoparticles like zinc oxide or titanium dioxide, 4-methylbenzylidene camphor, octocrylene, PABA, any kind of paraben, and triclosan. 

Certifications

Unfortunately, “reef safe” claims do not have a federally agreed-upon or regulated definition, so sunscreen manufacturers are not required to test and demonstrate that “reef safe” products won’t harm marine life. 

To avoid all potentially harmful chemicals, look out for the Protect Land + Sea Certification, which independently tests sunscreen products for the previously mentioned chemicals and updates their standards every other year to keep up with the most recent scientific findings in ecotoxicity. 

Forms 

As a rule, choose sunscreen lotion over aerosols whenever possible. Aerosol sunscreens are much less efficient because when we spray them, they create a chemical cloud, some of which doesn’t even land on our skin. When we spray aerosol sunscreen on a windy beach, much of it is blown into the sand and washed away into the ocean when the tide rises. 

A few takeaways: 

Wearing sunscreen is really helpful in protecting against the cancer-causing effects of sun damage. This is still scientifically-accurate. When you’re shopping for sunscreens, however, look for the Protect Land + Sea Certification if you can. At the very least, look for products free of oxybenzone and octinoxate, since we know that those chemicals are particularly harmful. When you go to the beach, consider staying in the shade and wearing as much clothing as you’re comfortable with so that you can wear less sunscreen while still protecting your skin. Studies show that a white cotton shirt will provide you with about 67% of the protection that a UPF (ultraviolet protection factor) shirt will, so you can probably protect yourself with clothes that you already own.