Sunscreen: Which SPF Should I Use?

We all know we need protection from the damaging UV rays. We also know that we need a cream, lotion or moisturizer with a high SPF. But what does high SPF actually mean? And what does SPF stand for? Could you prevent skin cancer if you choose a higher SPF? And what sunscreen protection would actually be recommended for you?

Let’s discover together how we can use the sun protection factor to reduce premature skin aging and prevent sunburns. More than this, we will have a look at how long SPF can actually protect you from the damaging effects of sun exposure and how to use the sunscreen to get the best possible benefits. But first, let’s see…

Why do you need SPF?

Sunscreen has multiple benefits for the skin, such as:

  • It helps prevent the occurrence of premature signs of aging at the level of the skin;
  • It helps keep the skin hydrated, even during prolonged sun exposure;
  • Can help prevent skin burns;
  • It reduces the risk of developing skin cancer.

To find out what is the best sunscreen, you need to take into consideration certain factors such as:

  • Your skin type;
  • The season/ the weather;
  • How long you’re planning to be out in the sun.

Despite some popular myths, you need to apply sunscreen whatever the season and your skin type might be. It is true that sun exposure is more dangerous during the hotter months of the year and for people with fair skin, but we all should use an SPF.

Protected skin with a sunscreen lotion
Diagram: skin protected with a sunscreen lotion, UVB and UVA rays can not penetrate into the skin.

What is SPF, and how is it measured?

Just imagine a protection foil that you use on your car, for example. You cover the car with the foil, and it keeps the paint intact for longer. Sunscreen acts in a similar way, protecting the skin from UVA and UVB rays.

SPF stands for sun protection factor. It is measured depending on the percentage of UV rays that can get through it and reach the skin. The higher the SPF is, the fewer UV rays penetrate the skin.

For example, an SPF 30 allows for a third of the UV rays to reach the skin. In other words, it can filter 96.7% of the rays. However, an SPF 50 can filter 98% of UVA and UVB rays. As you can see, the difference is not considerable.

However, you should keep in mind that it takes approximately ten minutes to get sunburns if you are out in the sun. If you use an SPF 30 lotion, it will take 30 times longer to get sunburnt, so approximately 300 minutes.

When you use an SPF 50 cream, it should take 500 minutes. And with an SPF 15 just 150 minutes.

How do you calculate the SPF you need?

As mentioned above, you should factor in your skin type and the estimated duration of sun exposure to determine the SPF you should get. So, how long do you think it takes your skin to get early signs of sunburn? For some, it might be ten minutes while for others, it could be half an hour or more.

Very fair sensitive skin

If you have very fair, sensitive skin prone to redness and irritation, then you probably shouldn’t go out in the sun without sunscreen, not even for 15 minutes. Actually, for this type of skin, you’d want to use an SPF 15 to be out in the sun safely for about 1 hour. If you use an SPF 30, you could be protected from the sun rays for about 2 hours. And an SPF 50 can ensure sun protection for 4 hours.

Normal, medium tone skin

For a medium tone skin, an SPF 15 can protect the skin for up to 3 hours. SPF 30 can be sufficient to keep you safe for about 4 hours and an SPF 50 for 6 hours, more or less.

Dark skin

If you thought that darker skin doesn’t need sunscreen at all, there are several recent studies that come to contradict this myth. Not only that dark skin can get sunburns too, but extensive sun exposure could also lead to skin cancer. In other words, the darker color of the skin is no guarantee that you are protected against UVB and UVA rays. The risk of developing skin cancer is there, whatever your skin type might be.

However, if your skin is dark, an SPF 15 can offer you protection for up to 4 hours, so much longer compared to people with fair skin. An SPF 30 could keep your skin protected for up to 8 hours or more.

But does this mean that you can just apply the SPF and stay out in the sun for 2-4-6-8 hours without a worry in the world? Well, definitely not! The weather and the activities you have when outdoors can also make a difference when it comes to how protected you are.

In summer, you’d want to wear a higher SPF lotion to get better protection from UVB rays. If you are swimming, showering or sweating, you should also reapply the high SPF lotion again to get the optimal level of protection.

How to correctly apply sunscreen

You might have read the instructions on a high SPF cream or lotion, and it always says to apply the sunscreen 20 to 30 minutes before sun exposure. But why not just apply the sunscreen when you get to the beach or the pool? Well, the skin is not perfectly smooth, and applying the sunscreen 20 minutes in advance can ensure the lotion covered and penetrated the skin evenly.

Even sunscreen products with high SPF should be reapplied every two hours. And this is even more important if you are sweating as some of the sunscreen might be eliminated due to profuse transpiration.

Applying sunscreen every two hours is important to ensure proper protection. With each application, the skin is more and more protected, and you can enjoy your time out without having to worry about sunburns later.

Then, there is the issue of the quantity of SPF that you should apply. Sometimes it’s written on the label to “apply liberally,” and this is a good recommendation. Dermatologists mention how people use just too little sunscreen, and hence the efficacity of the product is much reduced. You should apply an amount the size of a hazelnut to the face and about 35 ml on the body (about the size of a single espresso).

How to apply sunscreen to the face and neck
Diagram: how to apply sunscreen to the face and neck.

Types of sunscreen

There are two main categories of sunscreen to choose from depending on the active ingredient that is responsible for the protection.

Sunscreen absorbing UV rays

This type of sunscreen absorbs sun’s rays and converts them to heat. Some are broad-spectrum – so they absorb both UVA and UVB rays, others are just absorbing UVA rays as it is known that these rays can penetrate the deep layers of the skin and cause skin cancer. However, broad-spectrum SPF is always a good idea.

Mineral filter sunscreen (reflecting UV rays)

This type of sunscreen reflects the sun’s rays. The sunscreen contains oxides such as zinc oxide or titanium dioxide that can absorb and then reflect the rays. The mineral filters don’t penetrate the skin, and some consider them a healthier option compared to the sunscreen that absorbs UVB rays. Mineral filter sunscreen can also offer broad-spectrum protection.

Final words

There are many different types of sunscreen products – you can get a spray, cream, and even a tanning lotion with SPF. Whatever the texture and consistency of the product might be, it is the SPF number that counts. If you want to stay on the safe side and still can’t decide which sunscreen would be better for you, start with a higher SPF at first, and then you can switch to a lower SPF once you get a little tan. However, make sure to always use a sunscreen product when outside to keep your skin protected.


  1. American Academy of Dermatology Association. How do I know If I’m using the right sunscreen.
  2. Fitzpatrick, K. (2018). How much SPF do you need in your sunscreen. The University of Texas at Austin.
  3. The Skin Cancer Foundation. (2020). Does a high SPF protect my skin better.
  4. Environmental Working Group. What’s wrong with high SPF.
  5. American Academy of Dermatology Association. How to apply sunscreen.

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