Sun exposure is the main cause of skin cancer. This is because overexposure to the ultraviolet (UV) rays in the sunlight may generate free radicals that damage the DNA, resulting in skin cancer. Skin cancer can be further classified into melanoma skin cancers and non-melanoma skin cancers According to the Malaysia National Cancer Registry Report 2012 - 2016, non-melanoma skin cancer was one of the 10 most common cancers in males and females, respectively.
While it is impossible to completely eliminate skin cancer, the risks of getting skin cancers can be reduced through several measures:
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Minimizing sun exposure especially those with fair skin complexion.
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Avoiding sun exposure during the peak UV times during the day, typically from 9 am to 3 pm when the sun is directly overhead.
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Protect your skin by wearing protective clothing (long sleeves shirts and hats) when doing outdoors activities under sun exposure.
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Using a broad-spectrum sunscreen with SPF of at least 30 that blocks both UVA and UVB radiation. Apply at least one hour before sun exposure and reapply frequently.
In this article, we dive deeper into the selection of appropriate sunscreens for your lovely skin.
Understanding UV radiation
UVA and UVB are two main types of UV radiation in the sun rays. They differ in terms of their wavelength as well as their effects onto our skin.
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UVA has a longer wavelength of 320-400nm. It activates the melanin pigment within our skin to produce a short-term tan. UVA penetrates more deeply than UVB and can cause long-term skin damage and premature ageing.
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UVB has a shorter wavelength of 290 - 320nm, hence it only penetrates the uppermost layer of skin, i.e. the epidermis. Instead of activating melanin pigment like how the UVA does, UVB triggers the production of new melanin pigment and stimulates skin cells to produce a thicker epidermis, resulting in a long-lasting skin tan. UVB is the main cause of sunburn.
UVB is the form of UV irradiation most responsible for sunburn and has strong links to malignant melanoma and basal cell skin cancer risks. A sunscreen with a high SPF (sun protection factor) will help block UVB rays and prevent the skin from burning, and by extension damage that can cause skin cancer. Sunscreens with UVA protection will help defend the skin against photo ageing and potentially skin cancer as well. Fret not, as many sunscreens available in the market provide both UVA and UVB protection.
What is SPF?
SPF, or sun protection factor, is the measure of a sunscreenâs ability to prevent UVB from damaging the skin. It does not measure protection against UVA radiation. To measure protection against UVA, the UVA star system is adopted instead.
Image credit: https://findgoodbuy.com/best-sunscreen-sunblock-malaysia/
Is it true that the higher the SPF, the better it is?
If you had the experience of purchasing sunscreens before, you probably thought the higher the SPFs, the better the sunscreen is (and perhaps more expensive, also). The truth is, if your sunscreen has a SPF of 30, it is probably good enough for your usage. This is because the SPF scale is not linear, in that an SPF 30 is not âtwiceâ as protected as an SPF 15. In fact, SPF 15 blocks 93% of UVB rays, SPF 30 blocks 97% of UVB rays and SPF 50 blocks 98% of UVB. The difference from an SPF 30 to SPF 50 is only 1%.
In other words, above SPF 30, the amount of UVB protection increases minimally and does not offer as much protection as you might expect it to be. Nevertheless, there is no harm using sunscreen with more than SPF 30 if you can afford one.
Image credit to: https://www.hopedermatology.com.au/2019/03/14/how-to-choose-a-sunscreen-spf-myths-and-misconceptions/
Is the SPF used in moisturizers or cosmetic products equally effective?
Although the SPF used in moisturizers and cosmetic products should provide equal protection as sunscreens, there are other factors that may affect the SPF protection. These formulas are not as rub-resistant and water-resistant as sunscreens, and users usually apply them a lot more thinly than they would if applying sunscreens. As a result, SPF exists in these products may not offer the same level of protection if compared with sunscreens of equal SPF.
SPF in these products will help protect you against small amounts of UV exposure, such as when you walk to the car or hang your clothes outdoors, but sunscreen is better suited for longer, more deliberate UV exposure, such as spending your lunch hour outside.
It is also worth noting that such products containing an SPF may not contain any UVA protection and as a result will not protect against UV ageing.
Active ingredients in sunscreen
There are two types of active ingredients in sunscreens, and each protects you differently.
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Chemical sunscreens absorb the sunrays. Examples of such ingredients are oxybenzone, avobenzone, octisalate, octocrylene, homosalate, or octinoxate. These sunscreens are easier to apply on your skin without leaving skin residues. However, these ingredients are also associated with a few safety concerns, such as higher rates of skin allergies and hormonal disruption.
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Mineral sunscreens act like a shield that deflects sun rays. Examples are titanium dioxide and zinc oxide. These are more suitable for sensitive skin.
However, do not let some of the ingredient toxicity reports stop you from applying sunscreens, as the United States Food and Drug Administration (FDA) states that âthe risk of NOT using sunscreen is much greater than any potential risk posed by the sunscreen ingredientsâ.
Many sunscreens in the market offer a combination of two or more ingredients listed above. If you have sensitive skin, do check out the ingredient list of the sunscreen and only opt for those containing mineral ingredients only.
How should I apply sunscreens?
Applying sunscreen is not the same as applying other types of cosmetic products. Here are some key points to remember when applying sunscreens:
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Apply as per the packagingâs instruction. In fact, most people apply less than half of the amount required to provide the level of protection indicated on the packaging. If the packaging states âapply liberallyâ, you should probably apply a generous amount of sunscreen. When using sunscreen lotions, as the bare minimum you should to apply at least six full teaspoons (approximately 36g) to cover the body of an average adult, which is more than half a teaspoon of sunscreen to each arm and the face/neck (including ears), and just over one teaspoon to each leg, front of body and back of body. This is the amount used when those products are tested for their SPF (it equates to 2 mg /cm²).
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Remember to apply sunscreens on the more obscure body parts, such as back and the sides of the neck, temples, and ears.
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Apply sunscreen 15 to 30 minutes before going out in the sun to allow it to dry, and then again shortly after heading outdoors to cover any missed patches and to make sure youâre wearing a sufficient layer.
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Reapply sunscreen at least every 2 hours and immediately after swimming, sweating and towel drying or if it has rubbed off.
Is sunscreen water-proof?
Currently, there are no water-proof or sweat-proof sunscreens available in the market. Many sunscreen products are water-resistant but not water-proof. The nuance is that water-resistant sunscreens offer sunburn protection for 40 to 80 minutes after sun exposure. You may need to reapply sunscreen again after such a period of time.
Ask your pharmacist
Fret not if you are overwhelmed by the vast selections of sunscreen. You can always consult a pharmacist when choosing a sunscreen. You are encouraged to also get advice on various formulations (lotion, gels, sprays, oils etc.) of sunscreen available in the market.
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