Although most people now recognize that ultraviolet rays from the sun are damaging to the skin, most velieve that the application of a sunscreen on sunny days is all that is needed to prevent premature aging and/or cancers of the skin.
Women who wear makeup generally understand that screening out the sun on a daily basis is a good idea, but either rely on their foundation (base) to do this, or skip this step altogether.
To maintain a beautiful and healthy skin, it is important to understand that the rays of summer form only a small part of the skin's annual exposure to ultraviolet (UV) light. Day in, day out, the light that comes through our windows, or hits us as we go about our lives outdoors, exerts its damaging effects on the skin.
Worse, many sunscreen products provide inadequate protection against UVA light from the sun because the ingredients are not stable in sunlight and break down after limited exposure.
Your Skin at RiskThe sun emits three types of UV light: UVA, UVB and UVC. The shortest wavelength - UVC - is filtered out by the earth’s ozone layer. Both UVA and UVB sunlight reach the earth’s surface, and your skin. UVB rays, which comprise five percent of the rays that reach the earth, are the primary cause of sunburn and skin cancer. They are more prevalent in the summer, when the sun is directly overhead. UVB rays cause you to tan - the skin’s way of trying to protect itself from damage. These rays penetrate the upper layer of the skin (the epidermis) but go no deeper.
UVA rays make up 95 percent of the rays that reach the earth. They are with us every day throughout the year, even passing through glass windshields and windows. While they do not cause burning, their effect on the skin is far more insidious. UVA light penetrates deeply into the skin’s dermis, or underlayer, damaging the support structures (elastin and collagen) and causing the skin to wrinkle. In children and young people, this damage is, to a degree, repaired by the body. However, as we grow older and our skin accumulates more damage from UVA light, the damage cannot be undone.
Both UVA and UVB light contribute towards the development of skin cancer. To fully protect your skin from the ravages of ultraviolet light, it is important that you apply a sunscreen with effective UVA and UVB protection, daily.
Sun Protection and RatingsYou will likely be aware that sunscreens sold in Canada are marked with the product’s SPF (sun protection factor). This number refers to the degree of protection afforded against UVB sunlight. It does not refer to the product’s ability to protect you from the damage caused by UVA radiation. In fact, a sunscreen may have a high SPF, while offering no protection at all against UVA rays.
Sunscreens that provide protection against both UVB and UVA sunlight are known as broad-spectrum sunscreens and are usually marked as such on the packaging.
To provide UV protection, sunscreens rely on two types of ingredient - mineral (physical) blocks and chemical filters. Mineral blocks such as titanium dioxide filter the sun by reflecting light back from your skin. The rays of the sun literally bounce off them and so cannot harm you. Mineral blocks are derived from rock and are particularly effective at blocking UVB rays. However, they are limited in their action and are only able to provide protection for the surface layers of the skin. The longer rays of UVA radiation are still able to penetrate to the dermis and cause damage.
Chemical filters include Parsol ® 1789 and octocrylene. They work like sponges to absorb UV light, preventing it from reaching the deeper layers of the skin. Although they are effective immediately following application, just like a sponge, their power to absorb is eventually used up. (This is why sunscreen manufacturers recommend that you reapply sunscreen every two hours, irrespective of whether or not you enter water.)
Advanced Sun ProtectionWith the development of two innovative UVA filters - Mexoryl ® XL and Mexoryl ® SX - the ability of other chemical filters to retain their power to absorb UVA light has been enhanced. A highly stable and effective UVA filter in its own right, Mexoryl ® also combines with Parsol ® 1789, another highly effective UVA filter, to prevent its breakdown. Mexoryl ® has long been incorporated into higher quality European sunscreens and has undergone extensive testing for safety and efficacy. It is currently available in Vichy Capital Soleil sunscreens and sunblocks, which can be found in the Derma Skincare Solutions section of the London Drugs cosmetic department.
Interestingly, Mexoryl ® XL and Mexoryl ® SX work synergistically to increase protection against UVA and UVB rays. Used alone in a product, Mexoryl ® SX provides an SPF of 12. When used alone, Mexoryl ® XL provides an SPF of 8. However, incorporating both at half the concentration results in overall protection of SPF 20. The same applies to protection against UVA rays. Using the European PFA rating system for UVA protection (no such system has yet been approved in Canada), the inclusion of both Mexoryl ® XL and Mexoryl ® SX provides a total protection rating of PFA10 (high).