Sunscreen Ingredients and
The following are the FDA allowable active ingredients in sunblocks:
p-Aminobenzoic acid (PABA) up to 15 %
Avobenzone up to 3%
Cinoxate up to 3%
Dioxybenzone up to 3%
Homosalate up to 15%
Menthyl anthranilate up to 5%
Octocrylene up to 10%
Octyl methoxycinnamate (Octinoxate) up to 7.5%
Octyl salicylate up to 5%
Oxybenzone up to 6%
Padimate O up to 8%
Phenylbenzimidazole sulfonic acid (Ensulizole) up to 4%
Sulisobenzone up to 10%
Titanium dioxide up to 25%
Trolamine salicylate up to 12 %
Zinc oxide up to 25%
Tinosorb – meant to be applied to clothing via treatment/detergent
Mexoryl – not approved in the United States but available in Europe/Asia
From Wikipedia, the free encyclopedia
Sunscreen (also known as sunblock, suncream, suntan lotion) is a lotion, spray or other topical product that helps protect the skin from the sun's ultraviolet radiation, and which reduces sunburn and other skin damage, ultimately leading to a lower risk of skin cancer.
The best sunblock protect against both UVB (ultraviolet radiation with wavelength between 320 and 290 nanometres), which can cause sunburn, and UVA (between 400 and 320 nanometres), which damages the skin with more long-term effects, such as premature skin aging. Most sunblocks work by containing either an organic chemical compound that absorbs ultraviolet light (such as oxybenzone) or an opaque material that reflects light (such as titanium dioxide, zinc oxide), or a combination of both.
Many people apply sunscreen when participating in outdoor activities during the summer. However, some experts suggest wearing sunblock throughout the year to prevent cumulative damage, and to lower the risk of skin cancer. It is recommended that sunscreen be applied 30 minutes before exposure to the sun.
Dosing for sunscreen can be calculated using the formula for body surface area and subsequently subtracting the area covered by clothing. The dose used in FDA sunscreen testing is 2 mg/cm². From a sample calculation in a FDA monograph, if one assumes an "average" adult build of height 5'4" (163 cm) and weight 150 lb (68 kg) with a 32" (82 cm)-waist, that adult wearing a bathing suit covering the groin area should apply 29 grams (approximately 1 oz) evenly to the uncovered body area.
Sunblock inhibits the production of vitamin D. Though excessive sun exposure has been conclusively linked to some forms of skin cancer, there is some evidence that vitamin D may help prevent other forms of cancer. Season, geographic latitude, time of day, cloud cover, smog, skin type, and sunscreen all have an effect on vitamin D production in the skin, but fifteen minutes per day of direct exposure to the sun is a generally accepted guideline to follow for optimum vitamin D production
The History of Sunblock
The ancient Greeks used olive oil as a type of sunscreen. However, this was not very effective. Throughout the early twentieth century, H.A. Milton Blake, a South Australian chemist, as well as several other inventors attempted to create an effective sunblock but failed.
It was not until 1944 that the first effective sunblock was invented. At that time, World War II was in full swing and many soldiers were getting serious sunburn. A pharmacist named Benjamin Greene decided to create something that would save the soldiers from the sun’s harmful rays. In his wife’s oven, he created a sticky, red substance which he called "red vet pet" (red veterinary petrolatum), which worked primarily by physically blocking the sun's rays with a thick petroleum-based product similar to Vaseline. Greene tested it on his own bald head. It did not work nearly as well as modern sunscreens, but it was a start.
Sunblock has come a long way since its initial days. Modern products have much higher protection factors than Greene's sunscreen, and modern products can also be water- and sweat-proof. But there are also negative effects. Some people rely too much on the product and do not understand the limitations of the sun protection factor (SPF); they assume that buying anything over SPF 30 will automatically prevent them getting burnt no matter how long they can stay in the sun. Too much sunbathing is one of the major causes of skin cancer across the world.