Sunscreen is everyone's favourite skincare essential - its benefits are well argued but recently I have been thinking about it more carefully from a behavioral perspective. Is it worth the hype at scale? Do people really use it correctly?
What's undeniable about the state of affairs is the need for suncare - which is protecting the skin from the sun - this was accomplished with great aplomb before the invention of sunscreen - with hats and parasols and veils and generally seeking shade. The retro-meaning of shade was comparative darkness or coolness caused by shelter from direct sunlight. Say what you will re suncreams and sunglasses - there is nothing quite as effective as shade in protecting the skin from sun damage. You can bet anything that Rip van Winkle woke up to 99 problems but not wrinkles!
Now sunscreen is one of the top skincare products questioned for its dangerous ingredients - Oxybenzone - oy vey! Still there are more fundamental issues -
What is SPF - sun protection factor - to say a product has an SPF of 50 means the cream lets 1/50th of dangerous rays get through to your skin - that's 2% or 98% protection. SPF 30 means 1/30th or 3.3% danger or 96.6% protection and SPF 15 means 1/15 or 6.6% danger or 93.3% protection. I want to let these numbers sink in especially the difference between SPF 30 and 50. The incremental protection from SPF 50 over SPF 30 is 1.33% but only if both are applied at the right dose to begin with and reapplied in 2 hours when the UV index is 4 or greater.
Let's think about that. Is this how you intuitively use SPF 50 vs 30? You tend to feel more almost doubly protected with SPF 50 and far less likely to reapply than with SPF 15. Even knowing the relative protection rates you intuitively use less because it's sticky (except perhaps at the beach when you have not much else to do and the risks of burning are apparent) and stay out in the sun longer far longer than if the product is effective against sun damage.
The product is effective but it results in counterproductive behaviour that eventually costs more in sun exposure. This relates to an idea in economics called risk compensation where you feel a false sense of security and take more risks than you are protected against. It explains the lower rate of injuries in a game like rugby vs American football that is rife with concussions and chronic traumatic encephalopathy. Rugby players who don't wear helmets take fewer risks while playing while footballers throw themselves around with abandon. Going out into the sun wearing sunscreen results in approximately the same thing. You reapply less but importantly stay out longer than it's safe and this is far riskier than seeking shade.
Now I can never tell people to not wear sunscreen but a useful way to work around our natural tendency toward risk compensation is to act as if you aren't wearing any - hats, sunglasses, shade seeking. Just think to yourself - if I weren't wearing sunscreen what would I do - I would cross the street to the shadier side of the street. You could wear sunglasses and hats - maybe bust out a parasol. Get reacquainted with suncare.