Myths and Interesting Facts about Sunscreen

It's important to protect your skin from damage caused by ultraviolet radiation. To do it correctly, it's best to know the truth about sunscreen. Find out more in this article!

Reviewed and approved by the dermatologist Maria del Carmen Hernandez.

Written by Editorial Team

Last update: 21 November, 2022

Using sunscreen correctly is the best way to protect skin from damage caused by ultraviolet radiation. The purpose of this product isn’t to allow a person to spend more time in the sun, but rather to better protect them during the time they do spend in the sun.

There are two types of ultraviolet radiation: UVA and UVB rays. They both damage the dermis and increase the risk of developing skin cancer. For this reason, it’s important to use a sunblock that protects against UVB radiation, indicated on the label as SPF.

It should also protect you from UVA radiation, as indicated with the acronym UVA in a circle. 

Want to learn more?

We’ll tell you everything in this article.

Myths and interesting facts about sunscreen

Some urban legends about sunscreen have been passed down from generation to generation. And when it comes to something as serious as the health of your skin, it’s crucial to know the truth.

For this reason, we’ll go on to tell you about a series of myths and curiosities regarding sunscreen.

1. Myth: Being tan is healthy

Having a tan is not synonymous with health or beauty. According to researchers at the University of New Delhi (India), it’s one of the skin’s defense mechanisms in the presence of external aggression from ultraviolet radiation. 

Along these lines, dark skin is also susceptible to sunburn and suffering the damage caused by solar radiation.

2. Myth: You have to get dark to synthesize vitamin D

This statement is false. Although vitamin D synthesis is indeed promoted by sun exposure, after a certain point it is no longer stimulated.

For this reason, a study published by The Journal of Clinical Endocrinology & Metabolism suggests that you don’t need to sunbathe for hours. Just 10 minutes a day, three days a week is enough.

3. Myth: Sunscreen takes 30 minutes to take effect

This myth is linked to the belief that you have to apply sunscreen half an hour before being exposed to the sun.

However, you should know that sunscreen is effective from the moment it is applied, although it doesn’t become stable until after 10 minutes.

4. Myth: All sunscreens are the same

Not all sunscreens are equal. In this sense, pharmacists Antonieta Garrote and Ramón Bonet insist that their differences are based on the following factors: 

• The stability of their sun filters
• Their protection against different types of ultraviolet radiation
• Their adherence to skin
• Product texture, according to individual preference

5. Myth: SPF indicates the time protected

This is untrue. The SPF shows how many times longer you can be exposed to the sun to produce the same erythema, or reddening as if you hadn’t applied sunscreen.

This measurement only refers to protection against UVB rays. However, the truth is that no sunscreen can block 100% of solar radiation. Using two different sunscreens won’t increase the SPF either.

6. Myth: You don’t need more than one daily application

Sunscreen remains on the skin for a maximum of 2 hours. For this reason, it’s necessary to reapply the product often. You should also reapply it after swimming for more than 20 minutes, or if you’re sweating excessively.

Don’t forget that you should also apply it in the winter and on cloudy days since solar radiation passes through the clouds. 

7. Myth: You won’t tan if you apply sunscreen

Even if you use sunscreen, some amount of radiation enters the skin. This activates the body’s natural protection mechanism: the production of melanin.

If you’re tan, it means that solar radiation is harming the dermis and it’s producing melanin in an attempt to protect itself.

8. Myth: If I use waterproof sunscreen, I don’t need to reapply it

Specialist Leire Azcona Barbed explains that nowadays sunscreens are water-resistant for up to 20 minutes. However, some last longer, as indicated on the label in the following ways:

• Water-resistant: effective after swimming for 40 minutes
• Waterproof or very water-resistant: those which continue to be effective after swimming for 80 minutes

Correct usage makes all the difference

If you use sunscreen regularly, you will protect the dermis from aging, the risk of developing cancer, and other enemies.

Additionally, remember that sunscreen doesn’t last from one year to the next, since the filters lose their stability. Once the container is opened, the PAO specifies how long it can be used effectively. The PAO (period after opening) is the length of time after opening that the product will maintain its properties.