If you don't have sunscreen and are looking to buy some, read this before you head to the store. 

A non-profit called Environmental Working Group just published their 2011 Sunscreen Guide. After testing 17 hundred sunscreens, lip balms, lotions, potions and make-ups, here's what they came up with:

1. Don't Waste Money - Anything higher than SPF 50 is a waste of money. The Food and Drug Administration says an SPF of 80 doesn't offer any more protection than SPF 50. High SPFs can also make people more confident and thus, less likely to reapply.

2. Do Read Labels - There are four specific ingredients that offer the best protection that you should look for on the label. Avobenzone, Mexoryl SX, titanium dioxide and zinc all block UV-A and UV-B rays and they all stay on your your skin instead of being absorbed by it. Also try and find one that blocks IRA (Infra Red Energy) as 35% of the sun's rays are made up of IRA.

3. Don't Get Sunscreen With Insect Repellent - There's no information that shows it offers better sun protection and there are studies showing that insect repellent may cause cancer. No reason to give yourself cancer while you're trying to prevent it.

4. Do Use Enough - How much is enough? Guidelines suggest using about one ounce per uncovered body part. (Arms, shoulders, legs, chest, back, etc.) When applying, place about a half-dollar sized dollop in the palm of your hand, rather than squirting it directly onto the body part. If you need more, use more, and don't forget to reapply every couple of hours.

5. Don't Forget Your Face - A lot of facial moisturizers now have a built in SPF. Check your bottle or jar. If it doesn't have one, find one that does. Sun exposure is one of the leading causes of wrinkles and premature aging.

Finally, a lot of sunscreen products are labeled PABA free, but what the heck is PABA? PABA (or para-aminobenzoic acid) was once a main ingredient in sun protection products as a UV filter, but it turns out that it stains clothing and there is a significant chance you may be allergic to it.

This is just the Reader's Digest version. Want more? Click here.