Cover image for the article SPF 30 vs 50

SPF 30 vs 50:Does Higher Number Means Better Protection?

What comes to your mind when you think about a beach? Apart from the sand and sea and the unbearable crowd, sunscreen is a crucial part of visiting a beach. But it should not be limited to the sandy shores. It is something you should apply every day, whenever your skin is exposed to the sun. Choosing the right sunscreen could be tricky, especially with the SPF numbers on them. The most common ones are SPF 30 and SPF 50, so which SPF should you use? Do the numbers make any difference? Let’s put SPF 30 vs 50 “face to face” and see when the SPF number matters and when it doesn’t.

SPF stands for Sun Protection Factor and this is the component of the cream that provides protection from the Sun’s harmful rays. We won’t go into the details about how these rays cause damage but provide a brief explanation. 

Sunlight has various components and the visible light is just a part of it. These components are responsible for the various effects of the sun. The visible spectrum allows us to see things while the microwave and infrared give heat. The component of the sun rays that cause harm is Ultraviolet, mostly UVA and UVB. Sunscreens and SPF provide protection from these terrible two.

UVA goes deeper into the skin, underneath the epidermis while UVB mostly damages the upper layer of the skin. This is why UVB is the main reason for skin damage. UVA also contributes to skin damage, but its effects are mostly deeper, in the genetic level. This makes UVA a potent carcinogen. So the goal of using sunscreen is to protect the skin from UV rays, both A and B.

Illustration showing how UVA and UVB penetrates the skin
UVA penetrates deeper into the dermis while YVB damages the upper, epidermis layer.

The catch

The catch here is that no sunscreen can block out 100% of the UV rays. This is where the SPF numbers come in. Without complicating, the number of SPF indicates how much more UV protection is provided by the cream as opposed to naked, uncovered skin. So SPF 15 provides 15x more protection than not wearing sunscreen, 30 gives 30-times more protection, and so on.

So even if you get a sunscreen with, let’s say, SPF 1000, it would provide 1000-times more UV ray protection than unprotected skin, but never complete protection. Take a look at how much protection does SPF 30 gives as compared to SPF 50:

  • SPF 15 blocks 93% of the UVB rays
  • SPF 30 blocks 97% of the UVB rays
  • SPF 50 blocks 98% of the UVB rays 
  • SPF 50+ (60,85,100) block more than 98% but the increase is marginal, never 100%

While the jump from 93% to 97% does not seem that much, if you look at it the other way, SPF 30 provides more than double the protection than SPF 15. However, as the SPF crosses 50, the improvement is not that drastic, contributing only a fraction of percentage, but it is still there.

How sunscreen reflects the UVA and UVB of the sun
The layer of sunscreen reflects the UVA and UVB, protecting from damage

The misconception about SPF

Sunscreen with higher SPF provides more protection than their lower version, but NOT longer protection. This means that whether you apply sunscreen with SPF 15 or SPF 50, they both will lose their potency in about 2 hours. To understand it with an analogy, you can read the text in italics. If not, proceed to the next section. 

Imagine if you have a leaky roof. There’s water pouring inside your house. Consider SPF as an adhesive to seal the leakage. SPF 15 would stop most of the water, but there would still be a stream pouring in. SPF 50 would almost close the leakage but drops of water would still pour in, not as much as the stream with SPF 15. Both the adhesive only stay intact for 2 hours, after which you’ll have to reapply. 

It is better to seal the leakage using a better adhesive, but better does not mean longer.

The Spacefarer

Does SPF more than 50 provide extra protection?

A topic of debate that has resulted in many changes in the way sunscreen products are labeled is whether getting a sunscreen with a higher SPF number result is better protection? The answer to this question could be a yes and a no. 

In a research paper published in 2009, the efficacy of sunscreens was tested, comparing SPF 50 and SPF 85. The research was to see if anything beyond SPF 50 provides a substantial increment in UVB protection. 

The experiment was conducted in Vail, Colorado on a sunny day in the winters at an elevation of about 2,700 meters above sea level, when the UV levels peak, higher than the UV levels on summer noon! The two SPFs were tested on 56 subjects. 

With SPF 50, 8 people out of 56 were sunburned. With SPF 85, only 1 out of 56 was sunburned. This clearly showed that higher SPF does provide more UVB protection. You can read the entire research paper by clicking here. So why do doctors and even the FDA recommends using SPF 30 or 50 and not 85 or 100? 

The reason why you hardly ever see sunscreen with SPF 60 or more is that companies are not allowed to put numbers higher than 50 in the US and most of the other countries. If a sunscreen has SPF higher than 50, it is labeled as SPF 50+. 

This was done because people buying sunscreen with SPF higher than 50 assumed that it would provide longer protection. Which, as already established, is not correct. No matter what the SPF is, you’ll have to reapply the cream after an hour or two. This false assumption resulted in more skin damage. So to avoid such misconceptions, here’s a checklist to consider before buying sunscreen.

The effects of UVA, UVB and UVC on human skin
The effects of UVA, UVB and UVC on human skin

Things to consider while buying sunscreen 

While no information on the internet can replace a doctor’s consultation, here are some basic core things to consider while buying sunscreen. 

  • If you have light complexion, it is better to get a sunscreen with SPF 30 or higher. 
  • You can choose a sunscreen with SPF 50+ for better protection, but it won’t provide longer protection.
  • The general rule is to reapply the sunscreen (irrespective of the SPF) after 2 hours. Apply the sunscreen again if the skin comes in contact with water or you’re sweating a lot.
  • It is better to get water-resistant sunscreen as they manage sweat very well. 
  • Go for a broad-spectrum sunscreen. This means that it is capable of blocking both UVA and UVB. 
  • Whether the weather is cloudy, sunny, rainy, or apocalyptic, always apply sunscreen to the exposed skin. Always remember, if it’s daytime, it is UV ray time. 
  • Don’t save on sunscreen. Apply a generous amount and properly cover the entire skin. Not only the face, but any part of your body that is exposed to the sun needs protection.
  • And finally, since sunscreen cannot completely block UV rays, it is always better to physically protect the skin from it. Cover whatever you can from direct sunlight and avoid staying under the sun for a longer period of time.

This was all about the various SPFs present in the market and how to make the right choice. If you liked this article, how about reading some more? We’d love to have you around a little longer. Take a look at these articles and give them a read:

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One Comment

  1. SPF30 does not give ‘double the protection’ of SPF15.
    Measured against an SPF15, an SPF30 gives a mere 4% more protection but with nearly twice the chemicals needed in the formula to achieve this very small difference. Instead of taking about 225 minutes before you start to burn in the case of a 15, a 30 will give an extra 9 minutes!

    But no one should be staying in the sun for 225 mins anyway.

    And in fact all sunscreens no matter how ‘high’ the SPF must be reapplied at 120 minutes.

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