Why you shouldn't mix mineral and chemical sunscreens according to researchers

accreditation
0:00
play article
Subscribers can listen to this article

For the study, scientists from the University of Oregon and the University of Leeds created five different SPF 15 chemical sunscreen mixtures that included small-molecule UV filter ingredients approved for use in the European Union and United States.

They found these chemical, or non-mineral, sunscreens (without zinc oxide) had minimal changes in UVA absorption after being exposed to UV for two hours, indicating these formulations reliably protect the skin. 

However, one of the mixtures that contained zinc oxide had degraded other UV absorbers in the mixture. 

READ MORE | Ditch these 5 common misconceptions about sunscreen and shop our 10 SPF cream recommendations 

They found the UVA protection factor was reduced by between 84 and 91 percent in the sunscreen mixed with zinc oxide particles, while the original sunscreen without zinc oxide only showed a 15 per cent loss in UVA protection factor, after UV exposure for two hours.

"We still recommend consumers use sunscreen but suggest they should be careful to avoid mixing sunscreen with zinc oxide, whether intentionally with hybrid sunscreens that combine small-molecule UV filters with zinc oxide, or incidentally by mixing sunscreen with other products containing zinc oxide, such as makeup containing SPF," study co-author Professor Richard Blackburn shares.

Full study results have been published in Photochemical & Photobiological Sciences.

Follow us on social media here: FacebookTwitterInstagram.

Sign up to W24's newsletters so you don't miss out on any of our stories and giveaways.

We live in a world where facts and fiction get blurred
In times of uncertainty you need journalism you can trust. For only R75 per month, you have access to a world of in-depth analyses, investigative journalism, top opinions and a range of features. Journalism strengthens democracy. Invest in the future today.
Subscribe to News24
Voting Booth
Please select an option Oops! Something went wrong, please try again later.
Results
Yes, I believed it was authentic
7% - 400 votes
Yes, I didn't want to spend that much money on the original item
20% - 1155 votes
No, I always shop at reputable stores
13% - 757 votes
No, I don't wear designer clothing
60% - 3459 votes
Vote