Sunscreen use is an essential tool to prevent skin cancer, both melanoma and non-melanoma types. Over time the cumulative UV radiation exposure can cause DNA damage in the skin cells which can result in skin cancers and precancerous lesions called solar keratoses. Research shows that the use of sunscreen on a daily basis can reduce your risk of getting melanoma in half. But since sunscreen cannot block out all Ultraviolet radiation (UVR), thus it should be used in conjunction with protective clothing and sun-seeking behaviour.
In addition to serious effects like skin cancers, the sun is also the most common cause of skin aging which we call photoaging. There are two types of rays emitted by the sun called UVB rays and UVA rays. UVB rays are absorbed by skin cells and cause damage to cellular DNA. This can lead to sunburns and is related to eventual skin cancer. UVA rays, on the other hand, penetrate deeper in the skin and is the main cause of photoaging. The sun is thought to contribute 80-90% of what we see as visible signs of aging. This includes wrinkles, sun spots, visible blood vessels (telangiectasia) and loss of elasticity.
I am also frequently asked whether a sunscreen is needed on non-sunny days. The answer is of course, yes! You should use sunscreen in the winter or cloudy weather. This is because 80 per cent of UV rays can pass through clouds.
How you should choose a sunscreen
It is important to know how you should choose a sunscreen. When choosing a good sunscreen for your face, it is important to use one that is broad spectrum (covering both UVA and UVB rays) with an SPF of 30 or higher. SPF stands for “Sun Protection Factor” and it is the measure of the efficacy of sunscreens by focusing on the time it takes for UVB rays to cause the skin to go red.
When properly applied, a product with a SPF of 30 would allow 30 times as much time in the sun with the same level of redness as if without applying a sunblocker. A sunscreen of SPF 30 protects against 97% of UVB rays while SPF 50 protects against 98% of UVB rays. These values were determined when applying the correct amount. However, people often don’t apply the amount that is required. Thus, some people still experience sunburn after applying it.
How much sunscreen should I apply and how often should I apply the sunscreen?
Sunscreen needs to be applied every 90 minutes to get the SPF that is on the bottle. Many of us are guilty of not doing this!