How Does Sun Protection Factor (SPF) Work?

How Does Sun Protection Factor (SPF) Work?

Sun protection factor (SPF), we all know how important it is to wear and stock up before our summer holidays, but we are not ashamed to admit we haven’t the faintest idea what sun protection factor actually does or know completely how it works. So, we have done some research and we are going to share with you everything we have learnt about SPF in today’s blog post.

Before we dive in, I firstly wanted to explain in a little more detail what the differences are between UVB and UVA. Both of these rays damage the skin in their own ways, the easiest way to remember is UVB = Burning and has an effect on skin’s surface and causes the burning you can experience from too much sun exposure. UVA = Ageing, this generally means these rays can absorb deeper into the skin reaching the lower layers and causing skin ageing, such as the breakdown of collagen and elastin. It is UVA that is constantly present and requires all year protection from as it is able to penetrate through clouds, glass and water, many skin experts advise to wear a daily SPF, even on cloudy and overcast days for full skin protection.

What is SPF sun protection factor?

In short, sun protection factor is a product that is able to block the sun’s rays from causing any damage or burning of the skin. Generally speaking the higher the factor the more effective it is a blocking any UV exposure. By making note of which number there is on the SPF will guide you in understanding how long you are able to safely stay in direct sunlight before your skin starts to burn.

To get the best idea of how well the factor can protect your skin you consider how long it takes for your skin to start to look pink from direct sunlight, if your skin is the type to turn pink quickly opting for the highest factor will protect your skin from becoming burnt for a longer amount of time. When using an SPF 30, you can usually expect to have roughly 5 hours of sun protection this is determined by how long it takes for you to suffer from sunburn without any protection multiplied by the number of SPF.

To understand how long an SPF will work for you must do the following;

  • Take into consideration for your skin type and how easy it is for you to burn
  • Applying the correct, liberal amount roughly a tablespoon per limb, more if the area is larger
  • Making a note of the time you applied the SPF in preparation for reapplying
  • Reapplying if you are in water or sweating
  • Staying out of direct sunlight during the hottest part of the day

By remaining vigilant during your time in the sun you will find your skin remains protected without any signs of burning.

It is recommended that when protecting your face with SPF you use a product that has been formulated for the face to avoid any problem with congested and clogged pores that sometimes lead to breakouts. Always ensure you full cleanse the skin and follow with a high performing skincare full of active ingredients to keep the skin healthy, glowing and spot free.

How is the SPF of sunscreen determined?

The sun protection factor is a method of measuring the results of UV exposure and how long it takes to cause sun damage to the skin. It was first introduced in 1974 and although the results cannot be considered water-tight, allows the users of an SPF to keep on top of their skin exposure to the sun’s rays with UVB being the main one that works at protecting the skin from burning.

UVA is a little tricker to avoid as the effects of these rays are invisible, meaning you cannot see the results of sun exposure as quickly. This is why SPF broad-spectrum sunscreens were designed to protect the skin from both UVB and UVA. You can also check the inkey list of the packaging to see if the formula contains anything like zinc oxide or titanium dioxide as this will give you a higher chance of protecting your skin.

For long term benefits it is advisable to follow a safe sun procedure which involves staggered exposure in direct sunlight, liberal application of SPF to the skin, reapplying often and staying hydrated.  

When should you reapply your SPF?

The effectiveness of SPF begins to break down when exposure to direct sunlight, this makes reapplying sun protection an important step in your skincare routine.

If you are heading out to work and not expecting to stay out in the sun for long periods of time you will find the SPF you apply in your morning skin routine will provide ample protection during the times you are traveling to and from work.

If you are expecting to stay out for a longer amount of time than reapplying after 2 hours will ensure you will have the best sun protection. You will find there are a number of skincare products, particularly moisturisers, that contain an SPF and using them is a great start in sun protection. There is, however, a common skin myth which is if you layer a variety of different SPF products you are building a higher protection factor against the sun. Unfortunately, this is sadly not true, it is the highest factor that overrides any other you may have already applied to the skin. For example, if your moisturiser has a factor 15 in its formula before you apply a daily SPF 30, it is the 30 that will provide the skin protection.

What is the best SPF sun protection?

Any form of SPF sun protection is better than none at all! The formulas and ingredients found in everyday SPF products have come along in leaps and bounds since the 1970s meaning I am certain there is a product available for you. From SPF built-in to moisturisers, mineral solutions, sprays and every day, light-weight creams, no matter your skin type you will find a product that works at protecting your skin from UV exposure and damage, whilst not causing any other skin concerns, such as breakouts.

It is important to understand that all skin is the same in the sense it needs sun protection, so even if it’s a case of you popping on a hat or sunglasses or slathering yourself head to toe in sunscreen, you are making the effort to protect your skin, and it will truly thank you for it.


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