Photoaging and Sunscreen

You are my sunshine…You make me happy…

Sunshine is very bad for our skin, even though it is usually good for our mode. The ultraviolet (UV) component of sun exposure is the dominate cause of wrinkles and sunspots and leads to skin cancer. The sun on earth contains UVA and UVB lights and their effects are different although they are both bad for our skin. UVA is most abundant on earth, causes aging by producing free radicals, damages collagen fibers, and damages DNA indirectly. UVB is more energetic, causes sunburn, and damages DNA directly.

Chances are, you have already heard that UV light is bad for your skin and you are already using sunscreens and/or hat to protect yourself when you go out on a hot summer day. Then a little more knowledge in sunscreen and protective clothing can help you even further.


Sunscreens are rated by their sun protection factor (SPF). Most people think that the SPF number means how much longer you can stay out under the sun without getting sunburn. This is only true under the “ideal” conditions, and the ideal conditions are almost never met. Study has indicated that you need one table spoon of sunscreen just for your face in order to get an SPF that matches what’s on the bottle! To make the matter worse, organic sunscreens take 10 to 30 minutes to start working, and they degrade and become less effective over time in sunlight. All these mean that you need to apply plenty of sunscreens 10 to 30 minutes before you go out and reapply it every two hours. If you dislike putting a lot of sunscreen on your face, you can do what I usually do, grab a high SPF (40+) hat with wide brim all around.

The SPF rating of sunscreens only measures UVB protection since UVB causes sunburn. Some dermatologists believe that UVA contributes more to wrinkles than UVB since UVA penetrates deeper to the lower skin layers and damages more of the collagen and elastin in the lower layers. Sunscreens absorb both UVA and UVB are called “broad spectrum”, so look for both the “broad spectrum” on the label and look for certain ingredients which offer broad spectrum protection. Typical broad spectrum ingredients are: avobenzone, zinc oxide, and titanium oxide. A couple of very effective new UV absorbers worth mentioning are Meroxyl and Tinosorb. Both of them are very stable (comparing to standard and popular organic UV absorbers such as avobenzone), very effective, and available in most countries outside of US. Tinosorb is also used in laundry detergents and fabric softeners to increase SPF rating of fabrics, and this usage is FDA approved and available in US, such as in Rit SunGuard. This can be very helpful since a lightly woven white or pastel T-shirt only has an SPF factor of about 8. The SPF number can be raised to 15 after washing with Rit SunGuard five times and to 30 after ten washes.

If you are still not convinced how much the UV light can age your skin, compare the skin on your face with the skin on your inner thigh. Now which one would you rather have?