Meaning of SPF Sunscreen

SPF stands for Sun Protection Factor. It is a measure of how well a sunscreen will protect your skin from UVB rays, the kind of radiation that causes sunburn, damages skin, and can contribute to skin cancer.The rating tells you how long the sun’s UV would take to redden your skin compared with using no sunscreen 

There is a popular misconception that SPF relates to time of solar exposure. For example, many consumers believe that, if they normally get sunburn in one hour, then an SPF 15 sunscreen allows them to stay in the sun 15 hours (i.e., 15 times longer) without getting sunburn. This is not true because SPF is not directly related to time of solar exposure but to amount of solar exposure. 


It’s important to protect your skin from both types:

  • UVB rays cause sunburn and play a key role in developing skin cancer. A sunscreen’s SPF number refers mainly to the amount of UVB protection it provides.

  • UVA rays cause skin damage that leads to tanning as well as skin aging and wrinkles. The shortest wavelengths of UVA rays also contribute to sunburn. It’s important to look for the words “broad spectrum” on a product’s label, which means it has ingredients that can protect you from UVA as well as UVB rays.

Difference Between SPF 30 and SPF 50

  • SPF 30: Blocks about 97% of UVB rays.

  • SPF 50: Blocks about 98% of UVB rays.

The difference in UVB protection between SPF 30 and SPF 50 is only about 1%. However, this can be significant, especially for individuals with very fair skin or those who spend extended periods outdoors.Under ideal conditions (like in a laboratory), a sunscreen with higher SPF protection and broad-spectrum coverage offers more protection against sunburn, UVA damage and DNA damage than comparable products with lower SPF values.



 What Does the SPF Number Mean?

The SPF number  tells you how long the sun’s UV radiation would take to redden your skin when using the product exactly as directed versus the amount of time without any sunscreen . So ideally, with SPF 30 it would take you 30 times longer to burn than if you weren’t wearing sunscreen.

An SPF 30 allows about 3 percent of UVB rays to hit your skin. An SPF of 50 allows about 2 percent of those rays through. That may seem like a small difference until you realize that the SPF 30 is allowing 50 percent more UV radiation onto your skin.


Think UV, not heat


Many people mistakenly believe they only need sun protection on hot, sunny days. However, it is Ultraviolet (UV) radiation from the sun, not heat, that is the major cause of sunburn, premature aging, eye damage and skin damage leading to skin cancer.

UV can’t be seen or felt. Because of this, it can be damaging without us knowing it at the time. The UV index tells us the strength of UV radiation each day. Sun protection is recommended when the UV index is three or higher. Often, the UV can be high on cool, cloudy days

THE THREE TIPS YOU NEED TO KNOW WHAT SPF IS BEST

TIP #1

Always use a broad spectrum SPF for your face.

There are different types of sun rays, which carry different types of radiation. The two types we care about are the UVA and UVB rays. 

UVB rays cause burning. By penetrating just below the skin’s surface, they are responsible for burning and cancer. 

UVA rays cause skin aging. They penetrate deeper into the layers of skin tissue and cause more damage and aging to the skin. UVA accounts for 95% of the UV radiation that reaches the Earth's surface.

“Broad spectrum” sunscreen means it protects against both the UVA and UVB rays. So, look for “broad spectrum” on the label. 

TIP #2

What SPF is Best 30 vs 50

      SPF 30 What does it mean?

The SPF number you see on products ONLY measures protection against the 

UVB rays, not the UVA rays. 

SPF 30 means that 1/30th or ~3%t of the UVB radiation reaches the skin. In other words, SPF 30 gives you 97% protection against those UVB rays. 

      SPF 50 What does it mean?

If you use an SPF 50, that means you get 98% protection against the UVB rays. That’s only 1% more than 30. And frequently the higher SPF products, like 50, cost more. And if you have to pay 30-50% more to get only 1% more protection, is it worth it? 

When you consider SPF 15 vs 30 vs 50, generally, the higher the SPF, the better. But SPFs that are higher than 30 means the additional protection is minimal. 

Whether you choose a broad spectrum SPF 30 or 50, matters much less than using sunscreen daily every morning. And reapplying throughout the day if you are outside.

How to Use SPF Sunscreen

  1. Apply Generously: Use about one ounce (a shot glass full) to cover your entire body.

  2. Cover All Exposed Areas: Don't forget often-missed spots like ears, back of the neck, and tops of feet.

  3. Apply Before Exposure: Apply sunscreen 15-30 minutes before going outside to allow it to fully absorb into the skin.

  4. Reapply Regularly: Reapply every two hours, and more often if swimming, sweating, or toweling off.

  5. Use Daily: Even on cloudy days or during winter, as UV rays can penetrate through clouds and reflect off snow.

Importance of SPF for Melanated Skin

While melanin does provide some natural protection against UV rays, it is not sufficient to prevent skin damage. Here are a few reasons why SPF is important for people with melanated skin:

  1. Prevention of Skin Cancer: Melanated individuals are still at risk of skin cancers, including melanoma, which can be more dangerous due to later diagnosis.

  2. Avoidance of Hyperpigmentation: UV exposure can lead to dark spots and uneven skin tone, which melanated skin is more prone to.

  3. General Skin Health: Sunscreen helps prevent premature aging, fine lines, and wrinkles by protecting against UV-induced skin damage.

Using sunscreen daily, regardless of skin tone, is a crucial step in maintaining overall skin health and preventing long-term damage.