The sun and your skin: sunscreens

As the sunshine of early spring beckons us to the outdoors we must all remind ourselves of the dangers of overexposure to the sun. Once you have made the commitment to protect your skin from the sun the question is: how do you do it? There are literally hundreds of sunscreens, hats, sunglasses, and articles of clothing which claim to protect the skin from ultraviolet light. The first step to saving your skin is to learn to use sunscreens (also called sunblocks) correctly. 

Sunscreens are topical products which prevent ultraviolet light from reaching your skin by either, 1) absorbing the UV light, or 2) by reflecting the light; these will be listed as the active ingredients on the sunscreen label. The first type of sunblocker is an organic chemical. Each of these chemicals protects the skin over part of the ultraviolet spectrum, so the sunblock lotion must contain several of these to cover the entire range of dangerous rays.  The second type, light reflecting sunscreens, are inorganic substances, sometimes called physical sunscreens, which do not allow the UV rays to reach the skin, instead causing them to be reflected away. The two main physical blockers are Zinc oxide and Titanium dioxide. Zinc oxide has been used alone as a sunscreen for many years but was not popular because it was a thick white paste. Modern laboratory methods have succeeded in making zinc oxide in fine enough particles that it is transparent and invisible when used.

The sun protection factor (SPF) is a number which indicates the amount of UVB protection a sunscreen provides and a 15 SPF is the minimum for a complete sunblock. Products with a 15 SPF block about 93% of the UVB rays, while a 30 SPF blocks 97% and a 50 SPF blocks 98%. When chemical sunscreens were first created they concentrated on protecting from the UVB rays, which were known to cause sunburn and skin cancer and the SPF was developed to allow consumers to choose wisely. Unfortunately, we now know that UVA is a significant cause of both wrinkling and skin cancer, and many sunscreens advertise themselves as protecting from both, but there is not number similar to the SPF to measure how well a product works. The Food and Drug Administration (FDA) is now attempting to solve this problem by developing a measure for UVA protection. The effectiveness of a sunscreen is not dependent upon the form it is in: lotions, sprays and gels work equally well as long as the ingredients are correct. The best way to determine what sunblock to use is to visit The Skin Cancer Foundation website and check their guide to recommended products.

The most common cause of sunscreen failure (i.e. getting a sunburn while using sunscreen) is the improper use of the product.

The correct method of using sunscreen is:

1) Timing:  Sunscreens must be put on 30 minutes before going outside to allow the product to soak into the skin. If you put it on when you are sweating or wet it will wash off before it goes to work.

2) Amount:  Most people use far too little product to keep their skin protected. The correct amount of sunscreen for all the exposed areas is 1 ounce (2 tablespoons).

3) Reapplication:  Sunscreen is washed off in water and by sweat and should be reapplied every 2 hours or after swimming or heavy sweating.

Special cases: Sunscreen should not be used in infants under six months of age because their skin is too sensitive; they should be kept out of the sun by using sunshades and other protective covers.  For users who are allergic to sunscreen (which, ironically,  usually shows up as a bad sunburn), or who are just sensitive and have stinging skin or eyes from their products, there are sunscreens available which have only titanium dioxide or zinc oxide, which are non-reactive with the skin. The one problem with these products is that they sit on the surface of the skin and can be wiped off if the skin is rubbed, so they are not good for many athletes, such as tennis players, who towel off the sweat between points.

Lips:  The lower lip is a very common place for skin cancer, so don't forget to use lip balm with an SPF of at least 15, and reapply frequently, especially after eating.

Occupational exposure:  Golf courses, havens of skin cancer from many hours spent in the sun, are becoming more aware of the dangers of occupational exposure to ultraviolet light.  Scott McCracken of Captain's Choice Suncare, a 20 year veteran of the golf course, has developed a sunscreen dispenser which makes sunprotection quick and easy, and encourages workers to not skimp on their sunscreen applications.

Self tanners: These products, also called sunless tanners, contain dihydroxyacetone (DHA) which interacts with the keratin in the surface of the skin to form a golden brown color.  These products are safe to use and are a good alternative to tanning in the sun.  Just remember: they do not provide any sun protection and they can be an unsightly orange if overused.  It is a good idea to exfoliate before using because is the outer layer of the skin, the stratum corneum, is uneven and rough the tanner will not color evenly. 

Next: The sun and your skin: other sun protection methods