GreekGenes
Arch Nemesis of the Norwood Reaper
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1) Introduction:
Every fucking sunscreen says you should reapply within two hours. It did not take me long to realise that it's pretty much impossible to do so. Here's why:
1) As a guy at university or at work you can't excuse yourself to go to the bathroom and apply sunscreen in front of a mirror like a pussy every two hours. When other men see you, you'll be ridiculed.
2) Repeatedly applying sunscreen layers over and over, every two hours, will make you look OILY AS FUCK.
You could avoid the oiliness by cleansing your face between each sunscreen application but that would be too harsh on your skin and time consuming.
2) What does the actual science say?
Now on to the scientific part: there is ZERO evidence that UV-Filters (whether physical ones like Zinc Oxide, Titanium Dioxide or chemical ones like Tinosorb S, Tinosorb M, Avobenzone ) lose their efficacy after two hours.
A Sunscreen's efficacy depends on two things:
1) its photostability (meaning how much does it lose its protective effect under UV-exposure)
2) the amount of sweating, rubbing, touching of the person wearing it
So, a sunscreen's efficacy is NOT determined by how many minutes you wear it, but how much you expose yourself to the sun and how much you sweat or rub it off.
Unless you're literally spending your ENTIRE DAY UNDER THE SUN AT THE BEACH or YOU TOUCH YOUR FACE ALL THE TIME, you'll be fine with a single application of sunscreen.
3) Conclusion:
Applying sunscreen ONCE IN THE MORNING is enough for the average Western person to guarantee basic protection from the sun.
Worst case scenario: Even if a sunscreen loses 50% of its efficacy after two hours, it will still offer a significantly greater amount of protection than NO sunscreen.
Further reading:
www.paulaschoice-eu.com
pubmed.ncbi.nlm.nih.gov
Every fucking sunscreen says you should reapply within two hours. It did not take me long to realise that it's pretty much impossible to do so. Here's why:
1) As a guy at university or at work you can't excuse yourself to go to the bathroom and apply sunscreen in front of a mirror like a pussy every two hours. When other men see you, you'll be ridiculed.
2) Repeatedly applying sunscreen layers over and over, every two hours, will make you look OILY AS FUCK.
You could avoid the oiliness by cleansing your face between each sunscreen application but that would be too harsh on your skin and time consuming.
2) What does the actual science say?
Now on to the scientific part: there is ZERO evidence that UV-Filters (whether physical ones like Zinc Oxide, Titanium Dioxide or chemical ones like Tinosorb S, Tinosorb M, Avobenzone ) lose their efficacy after two hours.
A Sunscreen's efficacy depends on two things:
1) its photostability (meaning how much does it lose its protective effect under UV-exposure)
2) the amount of sweating, rubbing, touching of the person wearing it
So, a sunscreen's efficacy is NOT determined by how many minutes you wear it, but how much you expose yourself to the sun and how much you sweat or rub it off.
Unless you're literally spending your ENTIRE DAY UNDER THE SUN AT THE BEACH or YOU TOUCH YOUR FACE ALL THE TIME, you'll be fine with a single application of sunscreen.
3) Conclusion:
Applying sunscreen ONCE IN THE MORNING is enough for the average Western person to guarantee basic protection from the sun.
Worst case scenario: Even if a sunscreen loses 50% of its efficacy after two hours, it will still offer a significantly greater amount of protection than NO sunscreen.
Further reading:
How to use a sunscreen product | Paula's Choice tips
Learn how to apply sunscreen, how to use sunscreen in your skincare routine correctly, and much more | Paula's Choice: how to get healthy skin with SPF
Evaluation of sunscreen efficacy over time and re-application using hybrid diffuse reflectance spectroscopy - PubMed
Sunscreen efficacy is maintained over time in the absence of sweating or rub-off. After two hours of sweating, an 80 minutes water-resistant sunscreen does not need to be re-applied "at least every 2 hours."
pubmed.ncbi.nlm.nih.gov
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