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We all know that sun protection is a must-have no matter how tired we are. The number one enemy of premature ageing and pigmentation, basic sun protection is now seen as a part of basic skin care, rather than an optional step. But how much do we know about it? I speak to Dr Ang Por to find out the seven things you need to know about sun protection.

1. Understanding UVA and UVB
UVA and UVB are both sun rays. UVA is known as the ultraviolet long-wave, while UVB is ultraviolet shortwave. Both waves damage the skin in different ways, but the most important thing to note is that not all sun protection products protect you against both UV rays.

For example, an SPF product protects against UVB whereas a product with PA ratings protect against UVA. Only products that have both SPF and PA protect against the two rays. Confused? When looking for sun protection products, make sure they have both SPF and PA ratings, or the term “broad spectrum protection”. This means that the sun block has you covered.

2. What does SPF mean
Probably the most common term in sun protection, SPF stands for Sun Protection Factor. According to Dr Ang, “SPF is an indicator of protection against UVB. It indicates how much longer one can stay outdoors before getting sunburnt with that particular sunscreen.” For example, if a person gets sunburnt in 10 minutes without wearing sunscreen, wearing SPF 15 means he can stay outdoors for 150 minutes before getting sunburnt, according to Dr Ang.

Fair skinned people will tan more easily compared to people with a darker skin tone. This is due to the pigments in the skin acting as a “shield”. However, even if you are tanned, it does not mean you can go without sun protection, as UVB rays can still cause problems such as skin cancer.

3. PA+? PA+++? Does that mean People’s Association with a plus?
No, it does not. “PA is an indicator of UVA protection. This is the indicator most commonly used in Asian cosmetics,” says Dr Ang. You might have noticed that the rating ranges from PA+ to PA++++, the more “+” signs mean a higher level of UVA protection.

4. The difference between sunblocks and sunscreens
The difference lies in its ingredients, and how it protects your skin. Sunscreen refers to a chemical sun protector, whereas sunblock refers to a physical sun protector (more on this later). As the name suggests, sunscreen “screens” the UV rays before they enter your skin, converting them to a less harmful version of radiation before they are absorbed. Sunblock on the other hand, “blocks” the UV rays from entering your skin. Sunblocks act as a shield between the sun and your skin, deflecting harmful UV rays far far away.

5. There are two types of sun protection: Chemical and physical
As mentioned in point 4, sunscreens are chemical sun protectors and sunblocks are physical sun protectors. What does this mean? Chemical sun protection uses a plethora of ingredients to convert UV rays to less harmful versions before they are absorbed into the skin.

On the other hand, physical sun protection uses zinc oxide or titanium oxide to reflect UV rays off the skin. Most of us would rather UV rays be totally reflected off our skin, but according to Dr Ang, pure physical sunblocks tend to be thicker and whiter in texture, which does not make it ideal for daily wear (you wouldn’t want to look like a geisha!).

In today’s sun protection market, however, most sunblocks contain both chemical and physical sun protection. So you’re already getting the best of both worlds!

6. How much sun protection do I really need for a whole day?
If you work indoors and do not perspire much, Dr Ang recommends a minimum of SPF15 with some UVA protection, as UVA rays can penetrate through glass. However, if you’re a kiasu Singaporean, there is no harm applying a higher amount of sun protection – just opt for an oil-free sunblock with a light texture, as oily thick textures can clog your pores and aggravate acne.

7. Think twice about layering sunblock with SPF makeup
Yes, really. If your SPF makeup contains the ingredient avobenzone or Parsol 1789, your sunblock (or sunscreen) might almost be useless. Dr Ang says that avobenzone or Parsol 1789 is not photostable, which means that it degrades after prolonged UVA exposure. To combat this, sunblocks need to be stabilized with certain ingredients such as octocrylene and oxybenzone.

If you’re scratching your head and worrying that your sunblock has been ruined, fret not – I will be rounding up the best sun protectors on the market (that are also stable with SPF makeup!) in my next post. So stay tuned!

Dr Ang Por is the Founder and Consultant Dermatologist at Dermatology Associates (Paragon), 290 Orchard Road #15-05/06, Singapore 238859. For more information, visit