New 2022 Research is Out About Sunscreen Toxicity- A Summary of What You Need to Know!
New 2022 Research is Out About Sunscreen Toxicity-
A Summary of What You Need to Know!
Sabrina Schrope
Cosmetic Chemist, Owner of Vitamin You
It’s summertime again! As a cosmetic chemist, I’m seeing more news and media about how toxic and harmful *all* sunscreens are. As you may know, sunscreens help tremendously with preventing sun burns, skin cancer, and other UV effects. It’s misinformation to assume *all* sunscreens are bad.
Upon researching, I almost immediately found an excellent source on updated sunscreen toxicity based here in the USA. The National Academies of Science released an in-depth publication in August 2022 called:
Here’s a summary of what you need to know as a sunscreen consumer, starting with an overview of sunscreens, how they affect water, animals, and humans, and then a final conclusion.
Sunscreens
Firstly, most sunscreens will have a mix of UV filters and antioxidants to boost SPF factors. Each filter itself will have different physio-chemical properties, making any broad sunscreen conclusions inaccurate. For example, they all differ in biodegradability, water solubility, and marine life toxicity. Currently here in the USA, there are 17 major UV filters available on the market (although some are not in use). I’ve gone ahead and made this chart based on the publication’s findings:
Please note: Common names of UV filters are used within scientific research; however, these often differ from the names seen on sunscreen bottles, which are the “INCI names”. LC50 is the Lethal Concentration to kill 50% of a tested aquatic population- these populations will differ from one another and have not been tested on all aquatic populations. * Asterisked populations are assumed, not confirmed. Prevalence numbers are based on how many sunscreens contain the UV filter- the top 3 are bolded.
Sunscreens in Water:
- Most, if not all, sunscreens are not fully water soluble. Usually, like with zinc oxide, they will clump together with other water contaminants or particles, until they sink to the bottom. This sedimentation is below 0.1ug/g for all organic filters except octocrylene and octinoxate which have been recorded up to 2.4ug/g.
- Zinc and titanium are also naturally occurring in water; thus, the direct sunscreen implications are unknown when testing in natural water sources.
- In terms of water concentration of UV filters, the highest ever recorded was 10ug/L (PPB), which the vast majority of other filters have only been shown in concentrations below 1ug/L. In other words, although concentrations are extremely low, they do exist, and the data is not uniform.
Sunscreens in Animals:
- There isn’t enough research to conclude what happens to sunscreens if / when they come in contact with marine life. Current data looks at “lipophilicity” which is how oil-loving or cell-membrane-accepting a compound is. Only 7/15 sunscreens have been lab tested for this, and all have shown to be of medium bioaccumulation potential. It should be added that these are theoretical lab tests- not actually performed on marine animals.
- It also is not currently believed that UV filters pass from prey to predator as the food web gets to the top through a process called “trophic magnification”.
Sunscreens in Aquatic Habitats:
- The area of marine toxicity is still unregulated and lacks equivalence. It’s a very important area of research but does needs to develop a repeatable standard method in order to make comparisons. Again- because each study is vastly different, it’s hard to compare them.
- Most UV filters have been shown, or are estimated, to be toxic under 1,000 PPB. One concern, however, is that because most sunscreens are oil-soluble, they cannot dissolve fully in water. The best filter can dissolve up to 100 PPB in pure water but regardless, many factors can affect an organic compounds solubility in nature.
- There is currently no information on what happens to aquatic animals after the consumption of sunscreen.
- It’s also unknown how sunscreens interact with other environmental factors like pollution, global warming, salinity, physical disruption, and other minerals in water.
Sunscreens and Humans:
- Sunscreens have been shown and proven repeatedly to help prevent skin cancers, discoloration, sunburns, and more. Only about 1/3 of the US population wears sunscreen regularly but when it comes to outdoor recreational activities, up to 80% say they use sunscreen.
- Most sunscreen consumers don’t know what is in their sunscreen products and must rely on media to give them health information and recalls. It’s hard to say what outcome there will be if certain UV filters are found to be toxic to the environment. I would hope that new, safer, UV filters can be used in place of the old ones and consumers still prevent UV effects with sunscreen.
Conclusion
The publication ends with a huge call to action upon the US Food and Drug Administration (FDA), Environmental Protection Agency (EPA), and their various partners like the CDC, NIH, NOAA, and more to conduct and fund research on this topic.
Here is another chart I made with a conclusion on each UV Filter based on the information from this publication:
Of course, If you’d like to read the publication yourself, you can find it here:
National Academies of Sciences, Engineering, and Medicine. 2022. Review of Fate, Exposure, and Effects of Sunscreens in Aquatic Environments and Implications for Sunscreen Usage and Human Health. Washington, DC: The National Academies Press. https://doi.org/10.17226/26381.
Or online here:
<https://nap.nationalacademies.org/catalog/26381/review-of-fate-exposure-and-effects-of-sunscreens-in-aquatic-environments-and-implications-for-sunscreen-usage-and-human-health>