Sunscreen is an essential product for protecting skin from the harmful rays of the sun. While skin is easy to take for granted, continuing studies show that protecting skin with sunscreen and other similar products can make a massive difference in the overall health of the skin.
Why sunscreen is necessary
Skin has two main layers, the epidermis and the dermis. The dermis is the outer layer and in itself also has three living layers (the basal layer, the spinous layer, and the granular layer). The basal layer is that which is affected by sunlight, and where damage from exposure first occurs. Melanocyte cells within the basal layer produce melanin, the pigment in skin, and can be damaged by the UV rays in sunlight to become melanoma, or skin cancer.
Sunlight can be categorized into infrared (or heat), visible light and ultraviolet light. Within UV light there are UVA and UVB rays. The ultraviolet light in sunlight – or produced by tanning methods such as tanning beds – stimulates melanin production by the melanocytes. When there is not enough melanin, cellular damage causes sunburn. Over time, repeated exposure to UV light can mutate the melanocytes and result in melanoma; less pigment in the skin results in greater susceptibility to UV rays, which is why fair-skinned people have a greater incidence of skin cancer.
How sunscreen works
Sunscreens work by physically blocking ultraviolet light. Sunscreens may provide protection with various chemicals which act to either reflect the UV rays or absorb the radiation. White zinc oxide is a commonly used substance which, applied thickly, reflects UV rays. Para-aminobenzoic acid is a common substance that absorbs UVB rays, although it may cause an allergic reaction. Cinnamates also absorb UVB, while benzophenones absorb UVA and anthranilates absorb both.
The effectiveness of sunscreens
All sunscreens are graded according to SPF, or Sun Protection Factor. One easy way to calculate the efficiency of a sunscreen is to multiply the time that the skin can be exposed to the sunlight without burning by the SPF factor. For example, someone who can stay in the sun for 20 minutes safely would technically be safe for 200 minutes when using an SPF 10 sunscreen. However, studies show that most people do not apply sunscreen properly in amounts adequate to provide the graded level of protection, and doctors recommend a minimum of SPF 15 for general purpose use.
What happens without sunscreen
Skin that is repeatedly subjected to UV radiation over time may develop sun damage in the form of premature wrinkling, premature aging and even skin cancer. Special risk factors for UV ray susceptibility include fair skin, red or blond hair, light-colored eyes, easy burning of the skin, being prone to moles and freckles, high levels of sun exposure as a child or a familial history of skin cancer.
Sunscreen should be applied at least twenty minutes before intended exposure to strong sunlight and be re-applied regularly to receive the benefits of its protection. Many cosmetic products today have built-in sunscreen, but people are encouraged to still use separate sun protection products, as the level of protection offered by such products is not generally adequate to prevent sun damage. However, such cosmetic products can give an extra level of protection to additional products.