Use of Sunscreen
Updated: Apr 30
Most sunscreens on the market today will protect you from sunburns if they are used properly. The problem is that too few people use them properly. If you look on the back of a container of sunscreen, you will see in small print the instructions to “apply liberally," reapply within 80 minutes of swimming or sweating, reapply after toweling off and in any case reapply every 2 hours.
What does “apply liberally” mean?
Scientifically, it means apply it with a thickness of 2.0 milligrams per square centimeter. How many people can figure that out when applying sunscreen at the beach? And how many people forget to reapply it (also “liberally”) every two hours when they’re having fun, taking a nap or having a few beers? The answer is very few people. That’s why scientific studies show that sunscreen is not very helpful in preventing sunburn or in reducing the risk of melanoma.
In fact, a recent study of sunburns by the CDC and the National Cancer Institute of the National Institutes of Health found that 68% of persons reporting sunburn were using sunscreen at the time of their sunburn. Public health authorities and the medical establishment in general tend to ignore these studies and fail to warn the public about the ineffectiveness of sunscreen as it is actually being used.
So, when should you use sunscreen?
First of all, ignore the advice of medical authorities and the American Academy of Dermatology to apply sunscreen every day. Daily use of sunscreen is very bad idea.
Most sunscreens contain chemicals whose safety is questionable and daily use can result in them leaching into your skin and getting in your bloodstream with unknown effects. In addition, daily use prevents the sun from providing the health benefits described on this website and, if you are already suffering from insufficient sun exposure, will only worsen your condition. Lastly, daily use of sunscreen prevents your skin from gradually getting acclimated to the sun which increases your risk of getting sunburned.
Let’s look at a concrete example when use of sunscreen is a good idea.
Let’s say you have white untanned skin and 25(OH)D of 20 ng/mL. You have become convinced that you need more sun exposure for good health, and the day is sunny and bright. So you put on pair of shorts and and a short sleeve shirt, find a sunny spot at mid-day and go out and sit in the sun. You know that you are only supposed to do this for 10-15 minutes based on your skin type and your untanned status, but it feels so good you want to stay out longer. Or, maybe you’ve gone to the beach and you don’t want to leave after 10 minutes.
Now is this time for the sunscreen!
Squirt a huge amount of it the size of a golf ball into the palm of one hand. This is the amount you need to put on your body. Be sure to cover every square inch of your body with it. Repeat this procedure not less than every two hours you are out in the sun. If you go swimming, repeat as soon as you get out of the water. If it is a really hot day and you are sweating a lot, repeat every hour instead of every two hours. This is the way most sunscreens are meant to be used and should prevent you from getting burned. Compare all this to the protection from sunburn provided by a tan.
Click HERE to read about the SPF of a Tan.