Though, both the UVA and UVB cause skin cancer; UVA causes aging, wrinkling, and loss of elasticity of skin; whereas, UVB is responsible for sun burn and melanoma (Cancer of Pigment cells of skin called melanocytes).
|Severe sunburn and blisters on a shoulder, three days after a significant exposure to sun without sunscreen. (Photo credit: Wikipedia)|
Each year in America about 3.5 million cases of sin cancer are diagnosed and treated. If this trend goes on, one-in-five, that's more than 20 per cent of Americans, will develop skin cancer in a lifetime.
Melanoma, which used to be predominantly a disease of older men, is now the most common form of cancer for young adults in their late 20's, may be due to growing use of tanning beds (Now those emit more of UVA then before).
A broad spectrum sunscreen means protection for both UVB and UVA that is ideal to be used.
The protection offered by a particular sunscreen is expressed as SPF (Sun Protection Factor). SPF 15 filters out approximately 93 percent of all incoming UVB rays. SPF 30 keeps out 97 percent and SPF 50 keeps out 98 percent. SPF more than 50 does not have much relevance. As SPF 100 screens 98.5%.
|English: Two photographs of a man wearing sunscreen (spf 50) on one half of his face, in visible light (left) and ultraviolet light (UV-A, 340-355nm) (right). The sunscreen on the left side of his face absorbs ultraviolet, making that side appear darker in the UV picture. (Photo credit: Wikipedia)|
According to new guideline sunscreens can no longer be labelled as waterproof or sweat-proof. Those can be claimed to be water resistant.
Children under the age of six months should not be exposed to the sun and sunscreen; since their skin is highly sensitive to the chemical ingredients in sunscreen as well as to the sun's rays. Shade and protective clothing are the best ways to protect infants from the sun.
Children above the age of six months can use sunscreen. Even those who work inside are exposed to ultraviolet radiation for brief periods throughout the day, especially if they work near windows, which generally filter out UVB but not UVA rays (Glass can effectively filter 50% of UVA).
Many of the sunscreens available in the US today combine several different active chemical and physical sunscreen ingredients in order to provide broad-spectrum protection.
Usually, at least three active ingredients are called for. These generally include PABA derivatives, salicylates, and/or cinnamates (octylmethoxycinnamate and cinoxate) for UVB absorption; benzophenones (such as oxybenzone and sulisobenzone) for shorter-wavelength UVA protection; and avobenzone, ecamsule (MexorylTM), titanium dioxide, or zinc oxide for the remaining UVA spectrum.
To ensure full protection of a sunscreen, one need to apply 1 oz – about a shot glass full at one time. Studies show that most people apply only half to a quarter of that amount, which means the actual SPF they have on their body is lower than required.
During a long day at the beach, one person should use around one half to one quarter of an 8 oz. bottle. Sunscreens should be applied 30 minutes before sun exposure to allow the ingredients to fully bind to the skin.
No sunscreen is expected to stay effective longer than two hours without reapplication. So, same amount needs to be reapplied every two hours. Sunscreens should also be reapplied immediately after swimming, toweling off, or sweating a great deal.
Wearing sunscreen may cause vitamin D deficiency. There is some controversy regarding this issue, but few dermatologists believe (and no studies have shown) that sunscreens cause vitamin D deficiency.
Even If, it's cold or cloudy outside, one still needs sunscreen. Up to 40 percent of the sun's ultraviolet radiation reaches the earth on a completely cloudy day.
While buying one should look for The Skin Cancer Foundation's Seal of Recommendation, which guarantees that a sunscreen product meets the highest standards for safety and effectiveness.
Skin cancer is the most common cancer in the U.S., and the benefits of sunscreens outweigh potential risks from their ingredients; but, animal studies have raised some concerns.
Nanoparticles of titanium dioxide and zinc oxide have been linked to reproductive and developmental effects in animals. All Terrain AquaSport SPF 30, Badger Unscented SPF 34, and Kiss My Face SPF 40 claim to have no nanoparticles, but it has been seen that all had some. So did California Baby SPF 30+, whose website mentions “coated, micronized” particles.
Retinoids, part of the vitamin A family and an inactive ingredient in some sunscreens, have caused an increase in skin cancers in mice. There’s also a risk of birth defects in people taking oral acne medications containing retinoids, though they differ from the retinoids in sunscreens. As a precaution, pregnant women may want to choose a sunscreen without the ingredient retinol or retinyl palmitate.
Animal studies have indicated that oxybenzone, which is in many sunscreens, may interfere with hormones in the body.
The jury is still out on any harm from inhaling spray sunscreens. Until the FDA releases results of an ongoing study, avoid using sprays on kids, and spray sunscreen onto your hands before applying it to your face. Sprays are flammable, so let them dry before going near an open flame.
Consumer Reports tested 12 popular sunscreens for the July 2013 issue, and found some products don't meet the SPF claims made on the bottles. That means paying more for your sunscreen doesn't mean you're getting a more effective product.
All the suncreens evaluated by the magazine are broad spectrum. Testers wore the sunscreens on an area of their backs, then UVB rays from a sun simulator were shined on five spots within the sunscreened area. Additional testing for UVA involved seeing if the person tanned or turned red, and the products were also analyzed through wavelength testing to measure how well UV rays were absorbed by the sunscreens. They were also tested to see if they stained clothing.
Target's Up & UP Sport SPF 50, with an overall score of 80 came out to be in Top.
Six sunscreens, including the top scorer, were rated "very good overall" and were recommended by the magazine. They were: Wal-Mart Equate Ultra Protection SPF 50, Coppertone Water Babies, Walgreens Continuous Spray Sport SPF 50, Hawaiian Tropic Sheer Touch SPF 30 and Coppertone Sport High Performance SPF 30.
So, choosing, buying and using are important aspects of sunscreen to remain protected.