What is the Difference Between Sunblock and Sunscreen?

Living in sunny Singapore (or any tropical city for that matter) means that we get plenty of sun all year round. A lot of beauty experts have been advising everyone to slap on sunscreen or sunblock every single day. Even if we are staying indoors and think that we will not receive any harmful rays from the sun.

Sunscreen? Sunblock? Just what is the difference and therefore, what would it mean to use either one when it comes to skincare? Also, when buying a sunblock or sunscreen product, what do all those acronyms mean?

Let’s breakdown some simple terms first.


UV simply stands for “Ultra Violet” radiation and you probably know that. UVA is around us everyday, accounting for 95% of the UV radiation hitting the Earth’s surface and it is able to penetrate through glass. It is UVA which causes our skin to tan and due to its deep penetration, causes aging and loss of collagen over a period of time. This also causes those ‘age spots’ to appear years later.

UVB rays are shorter compared to UVA and do not significantly penetrate through glass. It is the UVB that usually causes damage on the top epidermal layers, causing the skin to redden and burn. It also plays a key role in skin cancer, tanning and aging of the skin.

SPF and the numbers


SPF stands for “Sun Protection Factor” and is a measurement of how well the sunblock or sunscreen will protect one’s skin from UVB rays. Unfortunately, it does not protect the skin from UVA rays.

The numbers attached to SPF shows the fraction of UVB rays that reach the skin. For example, SPF30 means that 1/30 of the UBV rays reaches the skin through the recommended thickness of product. It does not necessarily mean that the larger the number, the better the protection as it has shown that there is no significant difference between putting on SPF70 and SPF100.

Most dermatologists recommend SPF15 or SPF30 and that it should be reapplied every 2 hours.

Sunscreen vs. Sunblock


Basically, sunscreen is a chemical product which penetrates the skin and absorbs the UV rays before they are able to reach your dermal layer. The ingredients will break down after exposure to the sun, which is why it needs to be reapplied every couple of hours. It also tends to help to block out UVA rays, which is the one that causes dark age spots and tanning.

Sunblock on the other hand, is a physical layer that sits on the top layer of your skin. It acts as a barrier between the sun’s harmful rays and your skin by either reflecting or absorbing the rays. It usually comes as an opaque lotion, which is very obvious in white streaks across the faces or bodies of those at the beach. Sunblock usually lasts a little longer than your sunscreen products, unless you perspire which will cause the sunblock to wear off.

However, the best is to use a product that combines both sunscreen and sunblock. This is evident when the label reads “Broad Spectrum” or when you see the term “PA+”. This acronym is used mainly in Japanese products to stand for “Protection Grade of UVA” and is an indication of the UVA protection. The number of “+” also shows the level of protection, with PA+++ being the highest.

Have fun in the sun and remember to slap on that sun protection!

Photo credits: Laneige, Sulwhasoo and Pixabay

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