SPF Explained

SPF Explained

With sunscreen season in full effect we wanted to take a minute to dispel some common misconceptions around SPF. Those of us with sensitive skin typically reach for the highest SPF we can find, but what is the actual difference between SPF 30, 50, and 100?

UVA & UVB Rays

Let’s first cover what SPF actually is. SPF stands for “Sun Protection Factor” and it measures how much UVB protection a sunscreen product provides. Ultraviolet B (UVB) rays are what cause sunburn. These rays have shorter wavelengths and higher energy levels and thus produce more damage to the outermost layers of the skin. UVB rays also cause most forms of skin cancer.

It is important to know that SPF does not factor in UVA protection. Ultraviolet A (UVA) rays have higher wavelengths and lower energy levels and are much more penetrating than UVB rays. This means, UVA rays can affect cells deeper in the skin. These are the rays that cause premature skin aging and the more aggressive and harmful forms of skin cancer.

How Does SPF Work?

Now, let’s get into the different types of SPF and how effective they are.

You might be surprised to hear that the differences between SPF 5, 30 and 100 aren’t actually all that different. For instance, SPF 5 provides a UVB protection of 80%. The increase in protection becomes much smaller as the SPF gets higher - SPF 30 provides 97% UVB protection while SPF 100 provides 99%.

In 2012 the FDA proposed a rule that sets the SPF limit going forward to SPF 50+. On top of that, the chemicals used to boost SPF in chemical sunscreens are not favorable and could cause hormone disruption and allergic skin reactions.


Most importantly, make sure you are purchasing a broad-spectrum sunscreen. Broad-spectrum sunscreens provide UVB and UVA protection. There is a certain test products have to pass in order to legally claim ‘broad-spectrum’, so you know these products are safe and effective.

No sunscreen is 100% effective at blocking UV rays. So, remember to seek out shade or wear protective clothing during peak sun hours of 10am – 4pm and to reapply sunscreen every 2 hours, or more frequently if swimming or sweating. We recommend a broad-spectrum mineral sunscreen with the highest water-resistance of 80 minutes. Check out our lines of sunscreen for babies, kids, and adults!

Leave a comment

Please note, comments must be approved before they are published