One of the most important aspects of your skincare routine should be applying SPF, particularly during the summer months!

But what do those SPF numbers that we so often see on the front of sun cream bottles actually mean?

Understanding these numbers is crucial if you want to ensure your skin is protected from the sun.

That’s why we’ve produced this helpful guide to SPF. We’ll tell you everything you need to know: how SPF works and how to choose the right factor!

Source: Pixabay

How does SPF work?



You will have seen various sun cream products that offer differing levels of SPF. Most commonly, these include SPF 15 and 30.

But what do these numbers mean?

SPF is short for Sun Protection Factor. This refers to the ability of the sun cream to block UVB rays. However, it’s not linked to the heat of the day nor the strength of the sun.

Instead, it’s a simple multiplication sum which goes as follows:

SPF number x average time it takes to burn without sun cream = maximum time to spend in the sun

As you can see, choosing which SPF factor to use depends entirely on your skin type and how susceptible it is to burning.

So for example, if you normally stay out in the sun for 10 minutes before burning, using SPF 15 will allow you to stay out in the sun for 15 times longer than this time period. In this example, it would be 150 minutes.

Different SPF numbers

It’s estimated that SPF 15 products block on average 93% of UVB rays, whilst SPF 30 blocks roughly 97% and SPF 45, 98%.

However, we would urge you to play on the side of caution. Opting for a higher SPF can only benefit your skin and keep it well protected from harm.

In a similar vein, make sure to check that your sun cream includes protection against both UVB and UVA rays. This is generally common practice but it’s always best to check the labels.

sun cream beach Source: demitrisvetsikas1969

But, what SPF should I use?



We often select our SPF factor based on the temperature levels, the time of year and the level of tan we want to achieve. But one factor that often goes unmentioned, is choosing an SPF factor to suit your skin type.

This is ultimately the crux of the issue!

Know Your Skin Type

Knowing your skin type is a great way to help you determine the SPF you should be applying to your skin. There are six different skin types outlined by the Health Protection Agency which go from lightest to darkest.

Those with fairer skin, such as Type 1 and 2 are much more susceptible to burning than Types 5 and 6.

For example, those with Skin Type 1 will typically have very light skin and fair or red hair. You may also have a number of freckles and often, blue or green eyes.

Unfortunately this skin type burns incredibly easily and hardly ever tans. This is due to a lower production of melanin which protects the skin from the UV rays.

In general, the lighter your skin, the more susceptible you are to burning. For this reason, we recommend that those with fairer skin apply higher factors than those with Skin Types 5 and 6.

Lighter skin types are also more susceptible to skin cancers, so applying a high factor, like SPF 50 is a great way to protect your skin.

Genetic Skin Conditions

In a similar vein, looking at the history of any skin conditions that your family has experienced can be very useful in determining what factor to use.

For example, if a large percentage of your family have experienced skin cancer in the past, you will normally be more susceptible to developing this disease.

To protect your skin, especially among those that have a family history of the disease, it’s strongly recommended you apply a very high SPF, such as SPF 50 to minimise any further risks.

Photosensitising Medication

medication pills Source: frolicsomepl

Similarly, there are certain medications that can increase your sensitivity to UV rays, making you more susceptible to sunburn.

Photosensitive medication works when the drug either alters or becomes activated when exposed to UV rays. This can lead to inflammation of the skin and the reddened, sunburnt appearance.

Common drugs which induce this reaction include:

• Antibiotics
• Antihistamines
• Diuretics
• Acne medication
• Painkillers

So it’s worth having a look at any possible side effects of medication that you’re taking to allow you to take the necessary steps to protect your skin. If you’re taking any of these drugs, we recommend using a very high SPF to reduce the risk of sunburn.

When should you Reapply?



Unfortunately, there is no defined answer to this question. It depends entirely on how susceptible your skin is to burning, the sun’s intensity and how long you’re exposed to the sun.

Though using the SPF multiplication sum can be an effective method.

However, to give you a general idea, reapplying every 1 to 2 hours is a good option. It’s also worth remembering that if you get your skin wet, or rub your skin down with a towel, you should reapply instantly.



There you have it, everything you need to know about SPF and more!

So now there’s absolutely no excuse not to keep that skin protected. Just remember to reapply regularly and to use the best SPF for your skin type. That way, you’ll keep your skin looking youthful and prevent any sunburn!