I often get emails like the following:
“I use X sunscreen, after 15 minutes, I use a foundation.
The ingredients of X sunscreen are Drometrizole Trisiloxane (Mexoryl XL) 7%, Bemotrizinol 5%, Octisalate 5%, Octocrylene 5%, Avobenzone 3%, Homosalate 2%, Ensulizole 0.5%
The makeup contains Octinoxate 6.0%, Titanium Dioxide 3.8%, Zinc Oxide 3.0%.
Will this destabilize the avobenzone or affect the SPF protection?”
Usually, my response is that it’s impossible to know just based on the ingredients alone.
We need to be able to measure the changes we’re interested in. In this case with an SPF test performed on humans and a photostability test.
This is the only answer that isn’t completely hypothetical.
That’s how I respond, and almost every time there is a follow up question:
“If I used this sunscreen without avobenzone, would that be better? Should I change the makeup I am using? Should I wait longer between applications? Would that be better?”
I think this anxiety is partly due to a growing amount of science-washing in the beauty community.
People, brands, and retailers sometimes describe skincare down to an unrealistic level of precision and accuracy. Using scientific terminology, biochemistry, and statistics in a way that almost becomes untruthful or irrelevant.
But what’s most important is the removal of context. Experiments often simplify reality to their most relevant parts, and their results shouldn’t necessarily be extrapolated.
Scientific literacy isn’t just about recognizing and understanding equations, keywords, or jargon.
It’s also the ability to recognize what is being discussed and what isn’t, how it fits into the larger context, and when to apply or not apply new information.
This is the same with medical literacy. Yes, we have access to more medical information than ever before, but we don’t necessarily have the experience, or critical skills to diagnose or treat ourselves.
To people who have anxiety about whether they’re getting the “most” out of their skincare products, be they sunscreen or otherwise, I think these two thoughts are important to keep in mind…
It is impossible to “optimize” or “maximize” something if you can’t measure it.
Some is better than none.
