Monday, February 18, 2008

Coral-Friendlier Sunscreen

Recent research by a group of Italian scientists led by Roberto Danovaro suggests that many common sunscreen ingredients cause coral bleaching. To read my summary of how this happens as well as my criticism of the research, read my previous post.

Most news blurbs and blogs are reporting the culprit sunscreen chemicals as "a paraben preservative, cinnamate, benzophenone and a camphor derivative." If you go to check the list of ingredients on your sunscreen bottle, though, that list won't be much help unless you're an organic chemist. I want people to be able to make informed decisions about the kind of sunscreen they choose to slather up with, which is why I wrote this post.

While doing research about various sunscreen ingredients to write this post, I came across an excellent online database called Skin Deep created by the Environmental Working Group. They have rated hundreds of sunscreens by dozens of brands for their chemical safety and effectiveness in providing UVA and UVB protection. You can also read about specific ingredients and find products that contain the ingredients you specify.

These four common sunscreen ingredients were found to cause coral bleaching
(at potentially unnaturally high concentrations?) by Danovaro et al.:
Benzophenone-3 (Oxybenzone)
ethylhexylmethoxycinnamate (Octinoxate)
4-Methylbenzylidene camphor
Butylparaben (this is not an active ingredient but a common preservative in cosmetics)

These three ingredients did not cause significant coral bleaching:
Ethylhexyl salicylate
Butyl methoxydibenzoylmethane (Avobenzone)

All of the active sunscreen ingredients tested by Danovaro et al. were chemical absorbers (molecules that absorb UV rays before they damage your skin). Sunscreens with physical blockers (zinc oxide and/or titanium dioxide) rather than chemical absorbers are considered safer for you
and the environment. Skin Deep has a list of the 141 safest (for humans) sunscreen products, many of which lack the chemical absorbers listed above (although many of these products still contain ingredients listed above that caused coral bleaching, so read thoroughly).

Skin Deep also has product lists for active ingredients and ingredient combinations, such as zinc oxide, titanium dioxide, or zinc oxide and titanium dioxide together. You can look up your sunscreens to learn about the ingredients, or you can use the database to search for a new, better, safer sunscreen.

Some coral reef parks such as Xel-Ha and Xcaret in Mexico have restrictions on what kind of sunscreen you can use in the park. The requirements range from " must have the legend 'Oil Free' and natural ingredients. You can also choose any brand if it is labeled 'Paba Free' or 'Bio-degradable' " (Xcaret) to "biodegradable tanning product" (Xel-Ha). Both of these guidelines are vague and there are plenty of oil free and Paba-free sunscreens with the compounds found to cause coral bleaching. Danovaro et al.'s results as well as future research on this topic will hopefully help coral reef managers develop sound guidelines for sunscreen restrictions based on scientific research.

Happy snorkeling!


Left Brain said...

While you did an excellent job of analyzing the research by Danovaro et al, you could've done a better job investigating the data that went into building the Skin Deep database.

It was created using questionable data sources and designed specifically to present worst-case scenarios. They even state that some of the ingredients listed were entered by users and haven't been validated. You can see their methodology here.

The database is a handy listing of cosmetic chemicals but I remain skeptical of their warnings/ratings. But I'm a scientist and things compiled by lawyers with a political agenda never impress me. For better information consider consulting the CTFA (now the PCPC). It's biased in it's own way but at least it is run by scientists and not lawyers.

Keep up the great blogging.

Left Brain
The Beauty Brains
Real scientists answering your beauty questions.

Karina said...

Hi Left Brain,

Thanks for your comment! I spent *forever* on these sunscreen posts and it has made me sad that no one posted comments on them (though I know people are reading them).

I too am skeptical of the ratings listed on Skin Deep database. What I like about the database is that you can look up the ingredients and see a list of references to the research related to each ingredient. They make safety assessments, but at least they connect you with the resources used to make those assessments so that you can see for yourself. This appears to me to be different from the CTFA which connects people to the manufacturers of different components. The related site,, offers more resources directed at consumers about ingredients, but it seems to be focused more on the regulations.

Readers, here are links to the sunscreen information at and a post from The Beauty Brains about sunscreens.

Anonymous said...

I'm trying to find coral reef friendly sunscreen. All the chemical ones have something that is harmful to the reef. A lot of chemical free have parabens. "Mexitan" says it is biodegradable, no nano particles, but it has oils (coconut, jojoba, eucalyptus). Are oils harmful to coral reefs?

Johann and Sandra said...

Some brands that appear to be reef friendly (contain none of the ingredients shown to be harmful and are waterproof and biodegradable) are:

Caribbean Sol


UV Natural

Kiss My Face

Hope this helps, happy snorkeling!

Wayfaring Wanderer said...

Thanks for the info! I posted a link to you from my blog :D

Wayfaring Wanderer: 6 Sights to See on Highway 83 (Part 2)