During the Victorian era pasty white skin color was in vogue. Tanned bronze skin was popularized by fashion designer Coco Chanel in the 1920s. During World War II troops stationed in the south Pacific suffered from sun exposure and were then issued white skin cream (zinc oxide) for protection from the sun. These early sunscreens were heavy, greasy and opaque (easily visible after application). They also stained clothing. In the 1970s the FDA began to approve specific substances for use by manufacturers in sunscreens. These can be divided into 2 groups:
1-chemical sunscreens that react with sunlight converting it into heat to decrease damage (benzophenone, homosalate, methyl anthranilate, octyl methoxycinnamate, oxybenzone, avobenzone)
2-physical sunscreens that reflect the sunlight (zinc oxide, titanium dioxide, kaolin, ichthammol, iron oxide).
The physical sunscreens are more chemically stable and have less risk of causing skin contact sensitivity.
Zinc Oxide reflects light and protects over the widest range of light wavelengths than other sunscreens.
Through the 1980s and 1990s it became common knowledge that unprotected sun exposure caused prematurely aged skin and skin cancers. Sunscreens were increasingly recommended by physicians and this demand led to product improvements and the quality/variety of products available today. All sunscreens are not equivalent though.
The culprit is the ultraviolet (UV) component of sunlight. Its intensity increases in the summer, at higher elevations/altitude, closer to the equator, in the early afternoon, on sandy beaches after being reflected off adjacent bodies of water, on clear non-cloudy days and when reflected off white snow. Also as the ozone layer around the earth thins, due to pollution, it filters out less UV. UV has 2 components UVA (primarily associated with skin aging) and UVB (mainly linked to sunburns). Both are damaging to the skin and contribute to skin cancer development. UVA passes through window glass unless it is coated with UV absorbing film. Some sunscreens offer greater protection against UVA than UVB or vice versa. Suntanning booths are poorly regulated and expose you to both UVA and UVB.
Sun protection factor (SPF) is the time it takes for the skin to burn (turn red) on exposure to UVB rays. So if your skin would turn red in 10 minutes without protection it would take 150 minutes to do so from the same light intensity after applying SPF 15 sunscreen.
SPF 10 blocks 90% of UVB
SPF 15 blocks 92% of UVB
SPF 30 blocks 97% if UVB
Therefore above SPF 15 there are diminishing returns for further increases in SPF. Applying layers of sunscreen one on top of the other does not provide additional protection.
People who wear make up should apply sunscreen before putting on makeup and allow the product to set before applying makeup unless the makeup specifically contains sunscreen. Most makeup without added sunscreen provides minimal sun protection.
Since approximately 25% of lifetime UV exposure occurs before the age of 18 sunscreen use should begin at an early age. Since people of all skin colors get skin cancer everyone should use sunscreen. More than 3.5 million skin cancers in more than 2 million people are diagnosed annually and many of these could have been prevented by the daily use of sunscreens. Even on a cloudy day 80% of the sun's UV rays can pass through the clouds. Snow reflects 80% of the sun's rays and sand reflects 25%. Most windows do little to block UV rays from the sun. Therefore sunscreen use should not be restricted to warm weather or going to the beach. Even while driving in your car with the windows up and air conditioning on the application of sunscreen is important. It should be applied to all body parts not covered by clothing: face, ears, arms, hands, lips, etc. Apply the sunscreen to dry skin 15 minutes BEFORE going outdoors. Re-apply sunscreen approximately every two hours or after swimming or sweating heavily according to the directions on the bottle.
Added June 2011
The FDA announced new labeling regulations for sunscreens that will go into effect in June 2012. Those sunscreens with SPF of 15 or more that have been tested and proven to block both UVA and UVB sold in the US will have "Broad Spectrum" written on their labels. The companies will also be allowed to advertise the product as being able to prevent cancer and having anti-aging properties.
Addendum October 22, 2012
Researchers led by Sven Schneider, PhD, MA, of the Mannheim Institute of Public Health, Social and Preventive Medicine of Heidelberg University in Mannheim, Germany, polled 4,851 individuals in Germany aged 14 to 45 about their indoor tanning habits and found that 40% of respondents had regularly used tanning beds at some point.
Addendum October 30, 2012
A half million bottles of Banana Boat Spray Sunscreen Products are being voluntarily recalled after reports that 5 or more people caught on fire after applying the product and coming in contact with open flames before the sunscreen dried. The recall includes 23 Banana Boat spray sunscreen products sold from January 2010 through September 2012.
If a consumer comes into contact with a flame or spark prior to complete drying of the product, there is a potential for the product to ignite, according to Banana Boat's manufacturer, Energizer Holdings Inc of St Louis.
The recalled products include:
Banana Boat UltraMist Sport SPF 15 Continuous Spray 6 oz, 7965600979-8
Banana Boat UltraMist Sport SPF 30 Continuous Spray 6 oz, 7965600878-4
Banana Boat UltraMist Sport SPF 30 Bonus Continuous Spray 8 oz, 7965600955-2
Banana Boat UltraMist Ultra Defense SPF 30 Continuous Spray 6 oz, 7965604626-7
Banana Boat UltraMist Ultra Defense SPF 30 Bonus Continuous Spray 8 oz, 7965600956-9
Banana Boat UltraMist Sport SPF 30 Family Size Continuous Spray 9.5 oz, 7965605167-4
Banana Boat UltraMist Sport SPF 50 Continuous Spray 6 oz, 7965600933-0
Banana Boat UltraMist Ultra Defense SPF 50 Continuous Spray 6 oz, 7965604492-8
Banana Boat UltraMist Ultra Defense SPF 50 Bonus Continuous Spray 8 oz, 7965604549-9
Banana Boat Ultraist Kids SPF 50 Clear Continuous Spray 6 oz, 7965604495-9
Banana Boat Ultraist Sport SPF 50 Bonus Continuous Spray 8 oz, 7965604551-2
Banana Boat UltraMist Sport SPF 50+ Continuous Spray 9.5 oz, 7965605110-0
Banana Boat UltraMist Ultra Defense SPF 85 Continuous Spray 6 oz, 7965604654-0
Banana Boat UltraMist Sport SPF 85 Continuous Spray 6 oz, 7965604665-6
Banana Boat UltraMist Kids SPF 85 Continuous Spray 6 oz, 7965604916-9
Banana Boat UltraMist Ultra Defense SPF 85 Bonus Continuous Spray 8 oz, 7965604677-9
Banana Boat UltraMist Sport SPF 85 Bonus Continuous Spray 8 oz, 7965604679-3
Banana Boat UltraMist Sport SFP30 Continuous Spray 2pk 6 oz, 7965605374-6
Banana Boat UltraMist Sport SPF 50 Continuous Spray 2pk 6 oz, 7965605028-8
Banana Boat UltraMist Sport SPF 30 Continuous Spray 2pk 6 oz w/Sport Lotion & Lip, 7965605389-0
Banana Boat UltraMist Sport SPF 30 Continuous Spray 8 oz w/Sport Lip Balm, 7965607951-7
Banana Boat UltraMist Sport SPF 30 Continuous Spray 6 oz w/$1 Instant Redeemable Coupon, 7965607975-3
Banana Boat UltraMist Sport SPF 50 Continuous Spray 3ct 6 oz, 7965605464-4
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