SPF numbers have reached new heights, and though we generally like the idea of giving consumers the utmost protection from the sun, we aren’t convinced that the numbers should keep climbing. For example, Aveeno’s Active Naturals Positively Ageless Sunblock Lotion has an SPF of 70. The brand says that the SPF 70 will give more sunburn protection and that it retains SPF after 80 minutes of activity in the water. But how much better is an SPF 70 than say an SPF 30?

Contrary to popular belief, it isn’t more than double the protection. In fact, according to the Mayo Clinic, SPF is not an indication of how much time you can spend in the sun. American Academy of Dermatology spokesman and doctor James Spencer says that an SPF 15 product blocks about 94% of UVB rays, an SPF 30 filters out about 97%, and an SPF 45 product blocks about 98% of UVB rays. Double that, and a whopping SPF 100 only blocks out one percent more, at 99%. And, the beneficial effects of sunscreen decreases over time, so after a few hours the difference between the two may be lesser still.

The FDA has been in the works to change the guidelines to make it all a little more clear, even suggesting a cap at SPF 50. The FDA’s Dr. Matthew Holman says that there is no accurate test to prove sun protection factor above 50. This means that they would label products higher than that as a blanket SPF 50+. But these proposed changes have been in the works for years; they are now supposed to be put into effect in October.

Perhaps more important than sunburn is the effect of UVA rays, which are not calculated by SPF. Most worrisome is the link between sunscreen and the risk for melanoma, which we've discussed before; the FDA's changes would also incorporate a four star rating that would help distinguish how much UVA protection the product is capable of supplying.

Aveeno's Sunblock may block out a good portion of UVB rays, but active ingredients such as oxybenzone are slightly controversial; some even say they can have an adverse effect on the skin. Octisalate is used here in it's maximum concentration, and rightfully with other common sunscreen actives, since it is insufficient on its own and undergoes some kind of degradation when exposed to sunlight. Avobenzone has in some studies been absorbed by the body and secreted into urine, and is therefore not recommended to use on children or pregnant women. We are glad to see that the harmful PABA is not included anywhere in this product.

Regardless of the number, just remember that SPF must be applied properly for it to be effective. And though sunscreens with higher SPF ratings block slightly more UVB rays, none offers 100% protection. So be mindful of when and how much you apply and reapply!

Ingredients in Aveeno Active Naturals Positively Ageless Sunblock

Active Ingredients: Avobenzone (3%), Homosalate (15%), Octisalate (5%), Octocrylene (2.8%), Oxybenzone (6%)

Inactive Ingredients: Water, Styrene/Acrylataes Copolymer, Silica, Diethylhexyl 2 6 Naphthalate, Beeswax (Apis Mellifera), Caprylyl Methicone, Cetyl Dimethicone, Ethylhexylglycerin, Glyceryl Stearate, PEG 100, PEG 100 Stearate, Sodium Polyacrylate, Fragrance (Parfum), Caprylyl Glycol, Acrylates/C12 22 Alkylmethacrylate Copolymer, Ethylhexyl Stearate, Dimethicone, Xanthan Gum, Algae (Algae Extract), Trimethylsiloxysilicate, Disodium EDTA, Tanacetum Parthenium (Feverfew) Leaf/Flower/Stem Juice, Dipotassium Glycyrrhizate (Licorice Root), BHT, Trideceth 6, Ganoderma Lucidum (Mushroom) Stem Extract, Lentinus Edodes Extract, Polyaminopropyl Biguanide, Methylisothiazilinone, Tocopherol, Glycine Soja (Soybean) Seed Extract