Sunscreen 

Most people take sunscreen for granted.



It is something they slap on when they go to the beach, swimming pool or a day in the park and have no idea that UVA or UVB are. Yet it is important to know what kind of sun protection is needed and to what degree. About 90% of cases of premature skin aging are attributed to UV radiation, so it is critical that sunscreen is used correctly.



Of course, the best prevention is to avoid exposure as much as possible, especially between 10 am to 3 pm when the sun is at its most intense. But if it cannot be avoided, wear sunscreen properly.

Sunscreen is also known as sun block and can be in the form of a lotion (most popular) or a spray and is designed to “block” the ultraviolet (UV) radiation from the sun from activating little cancer cells on the skin. Mostly people consider sunburn as first sign of sun damage that will eventually lead to skin cancer, but actually sunburn is as a result of UVB (wavelength 290 to 320 nanometers) radiation and although it does nothing for the skin (as it destroys collagen) it is not as harmful as UVA radiation (320 to 400 nanometers) which causes long-term damage to the skin (photo aging) where it does not show. It is sneakier than UVB and is harder to block, unfazed by glass as UVB is and with deeper penetration than UVB. UVA and UVB radiation effects is measured typically according to a Skin Phototype (SPT) classification, with Type I and II being the most sun-sensitive.

Most sunscreens protect against UVB with the use of a chemical compound i.e. oxybenzone that absorbs UV radiation. For protection against UVA as well, sunscreen that uses materials or minerals such as zinc oxide that physically blocks the radiation by reflecting it is recommended, or a mix of both types for maximum protection. A new formula that mimicked the efficacy of zinc oxide without the drawbacks is the use of micronized titanium dioxide.

Sun Protection Factor (SPF) is commonly used to describe the effectiveness of sunscreen against UVB. The higher the SPF, the more effective is the sunscreen. However, it does not mean that it protects against UVA unless it contains radiation blockers titanium dioxide or zinc oxide. An SPF of at least 15 and either of these two radiation blockers is recommended for protection against both UVA and UVB.

Having the best sunscreen is not enough, however. Enough needs to be applied for the sunscreen to be effective. A film should form over the areas that will be exposed to the sun when initially applied, which should be about half-an-hour before exposure as it takes approximately that time for the skin to absorb the sunscreen. If makeup is to be applied, the sunscreen has to go on last thing to prevent breakdown when applied under water-based foundations or moisturizers. Sunscreen needs to be reapplied after swimming or excessive sweating or being rubbed off by a towel. Otherwise, research recommends re-application 30 minutes after the first application and then no more.

For effective protection, low SPF sunscreen should be applied daily rather than occasionally with higher SPF sunscreen. When used in conjunction with insect repellents, its efficacy is reduced by about 35%, which means it needs to be of a higher SPF and reapplied more frequently.