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Sunblock, Sunscreen, and SPF.. What Exactly Are They?

You have probably been exposed to the concept of sun protection from your mother insisting you put on sunscreen and wait a few minutes before jumping into the water. You’ve probably also used sunblock, sunscreen, and SPF interchangeably to mean sun protection; but what exactly are they and what are their differences? While they do fall into the category of sun protection, they each have different functions.


  1. Ultraviolet Rays (UV Rays) are solar energy radiation. UV Rays may not only cause damage over time, but can also leave immediate burning to skin if it is left unprotected over a period of time, depending on the amount of sun exposure. They are proven to be human carcinogens.

  2. UVA Rays are long wavelength radiation, responsible for 95% of radiation that reaches the Earth's surface and can penetrate into our skin and is responsible for most skin damage.

  3. UVB Rays are medium wavelength radiation that are mostly blocked by the Earth's atmosphere but can still cause delayed tanning and burning of the skin.

Sun Protection and Why We Need It

The most obvious reason for using sun protection is to prevent burning from the heat of the sun. Sun protection products don't necessarily lessen the heat that we feel from the sun, but they act as barriers or layers that shield us from the damage that we can get from that heat. Our sun emits solar energy radiation that are harmful to us even though we don't see them so sun protection is vital to keeping our skin healthy.

Skin cancer (melanoma) can develop from lack of protection from harmful UV rays. According to, "On average, a person’s risk for melanoma doubles if they have had more than five sunburns, but just one blistering sunburn in childhood or adolescence more than doubles a person’s chances of developing melanoma later in life."

Sun protection is definitely not something to be taken lightly. After all, our skin is the largest organ of our bodies and the one that is most exposed, so it just makes sense that we care for it as much as we care for our internal wellbeing.


Sunblock, as the name suggests, acts as a blocker and barrier against solar energy radiation that is more popularly known as UV (Ultraviolet) rays. In the past, most sun protection was really just sunblock. Sunblocks are those thick creams that our parents would smother on us and leave us looking white and ashy, although many invisible sunblocks have come out that don't leave this ugly white cast. Sunblock's main purpose is to physically block UV rays. They sit on top of the skin, leaving a film composed of oxides that block the harmful rays. That layer deflects the UV rays instead of allowing the radiation to penetrate the skin.


Sunscreens, unlike sunblocks, act more like a filter. Sunscreen is a filter that lessens the amount of radiation that gets through to our skin and also uses chemicals to transform the harmful UV rays into something non-damaging to our skin. Sunscreens are made up of chemicals such as avabenzone and oxybenzone that work well to transform harmful UV rays but since they use strong chemicals, some may have negative reactions to this. A lot of people prefer sunscreens over sunblocks because they feel lighter on the skin and aren't as sticky as good ol' sunblocks do.


Finally we have SPF. SPF isn't another type of sun protection product. The US FDA describes it as "... a measure of how much solar energy (UV radiation) is required to produce sunburn on protected skin (i.e., in the presence of sunscreen) relative to the amount of solar energy required to produce sunburn on unprotected skin. As the SPF value increases, sunburn protection increases."

We all have heard the common misconception that the higher the SPF, the longer we have to reapply sun protection. While it is partly true, it isn't exactly a direct relation. The amount of time with sun exposure is not directly related to SPF, but rather SPF is directly related to the amount of sun exposure one gets. For example, your exposure to solar energy for one hour at 9:00 in the morning is just the same amount of sun exposure for 15 minutes under the sun at 1:00 in the afternoon. This means you may need to reapply more sun protection if you are exposed at peak sun exposure times. As a general rule, it is best to get the highest SPF you can get your hands on.

Choosing the One For You

Before going out to buy your next sun protection staple, it would be helpful to take note of these considerations and how they might work with your skin and your lifestyle. If you have very sensitive skin, it would seem that sunblocks are a better option as they do not have skin-penetrating chemicals that may irritate the skin.

Use of sun protection is not only for pool and beach days out. We are exposed to the harmful UV rays every single day. A quick grocery run or working beside the window can be harmful to our skin without appropriate sun protection. This damage can build up over time and may lead to premature aging or even, in bad cases, melanoma. Daily use of sun protection on the face and the most exposed areas of our body would be beneficial.

Helpful Reminders

  • Sun exposure from 10 AM to 3 PM is most harmful. Apart from wearing sunblock and/or sunscreen, put on proper clothing (sun hat, long-sleeve clothing or rash guards, etc) and try to stay in a shaded area.

  • Get a broad-spectrum SPF product with a water-resistant formula.

  • Don't skimp on the product, apply an ample amount.

  • Reapply every two hours (individuals with lighter skin tones may need to reapply more often).

  • Avoid any type of sun protection products for babies 6 months and below. Use rash guards or a sun hat instead.

  • The higher the SPF, the better.

Happy (protected) splashing! ☀️ #uniquelycolorful


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