SPF? UVB? UVA? Understanding Sunblock and Finding the Right One for You

Just about everyone knows that it is important to protect your skin from the sun, especially in a country as close to the equator with as many sunny days as Thailand. Unfortunately, it’s not always so easy to know how to go about doing so. Walking into a convenience store and trying to choose the correct form of protection can sometimes feel overwhelming. With so many options available, it helps to have a little bit of expert advice, which is why the medical professionals at Bangkok Hospital Siriroj Cosmetic Skin Center are here to answer some common questions.

Surprising tips that will save your skin from the sun

What is SPF and how much of it do I need?

From tanning oils labeled SPF 15 to expensive sunscreens labeled SPF 50, this term is thrown around all the time. SPF stands for “sun protection factor” and it protects you from harmful ultraviolet (UV) rays that cause sunburns and can contribute to skin cancer. Dermatologists agree that wearing sunscreen with adequate SPF isn’t just for a day at the beach. Especially if you plan on spending a fair amount of time outside, you can benefit from wearing it every day. But how much SPF do you really need? While clever marketers may try to convince you that a bigger number is always better, this is one case in which it does not actually make that much of a difference after a certain point. A sunscreen with SPF 30 will protect you from about 97 percent of harmful UVB rays, while a sunscreen with SPF 50 will protect against 98 percent. So, yes, the higher the number, the more the protection, but once you go over SPF 30, the difference becomes all but negligible. The more important thing is to remember to reapply it regularly throughout the day.

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What does UVB mean?

The sun releases two harmful varieties of ultraviolet (UV) rays. UVB rays not only cause sunburn, but also are more instrumental in causing certain types of skin cancers, including the dangerous malignant melanoma. Sunscreen offers more protection against these kinds of rays.

What is UVA?

The sun produces approximately 500 times more UVA rays than UVB rays. Unfortunately, sunscreens are less effective against these. UVA rays play a bigger role in photoaging, which causes the skin to wrinkle and discolour over time. They also contribute to certain kinds of skin cancer.