The facts about sun damage and suncreen

Ok, some of you are off for spring break to a place that is sunny and warm (hopefully). But new research from Yale University published in the journal Science (Feb.20, 2015)  indicates that UV irradiation causes both direct damage (DNA dimer formation that causes mis-reading of a DNA strand) during UV exposure, but can also create reactive oxygen and nitrogen species (free radicals) that act on the melanin in our skin for at least 3 hours AFTER exposure to UV light. This damage happens with BOTH  sun exposure as well as tanning bed exposure- any UV exposure.

This data  indicates that melanin that protects us from the sun, may also cause cancer as well. This reinforces the notion that there is no such thing as a protective “base tan”. It is all DNA damage, plain and simple. And will continue to harm you long after you leave the sun.

So… on that note, I wanted to let you all know that sunscreens work! But sunscreens are water-resistant, NOT waterproof, or sweatproof.  Water resistant means that they will protect you for about 40 or 80 minutes in the water (depending on the type you purchased), but then have to be reapplied. Also, did you know that an SPF rating of 15 absorbs 93% of UV rays, and that 30% absorbs 97%? Any sunscreen rated higher than an SPF of 30 may be fudging their numbers, as it is almost impossible to stop more than 97% of UV rays. And with this in mind from the same article:

The rules also say only sunscreens with a sun protection factor higher than 15 can claim to reduce the risk of skin cancer, aging, and sunburn, and that those rated SPF 2 to 14 must be clearly labeled as not doing so.

So that means, if you use a sunscreen with an SPF of less than 15%, you are at risk for ALL of those: aging, cancer and sunburn.

So remember, have fun in the sun, but use a sunscreen of at least 15% and reapply often!!!


Happy spring break.


This entry was posted in Cancer, microbiology. Bookmark the permalink.