Sunscreen 101: Your Burning SPF Questions Answered

Sunscreen Guide Erica Bracken

I usually steer clear of beauty trends, but there’s one skincare essential that’s having a renaissance right now and I’m so here for it: sunscreen.

Previously, knew sunscreen was important, didn’t really know how it worked, and made sure to apply it on beach holidays (or at least our mother’s made sure we did.)

However, the then thick, pore-clogging, heavily scented formulas were applied on a needs-must basis, and most often left in the beach bag for the rest of the year.

Now, thanks to technological advances and an influx of new, aesthetically pleasing, cool brands, sunscreens have transitioned from gloopy to glowy.

Think silky, sheer and weightless formulas that don’t leave an ashy shade on dark skin tones, suit all skin types, sit comfortably under makeup, and, most importantly, offer high protection that you’ll actually want to wear.

In perhaps one of the most healthy and helpful social media trends out there, it’s not uncommon to see your favourite influencers share their must-have sunscreen products and diligently remind their followers to wear SPF every. single. day.’

However, despite the advances in technology and public profile, there still exists some confusion around sunscreen. Do we need to wear it every day? How much do we apply? If we tan, can we wear less SPF protection?

I’ve answered all your burning sunscreen questions in the article below, so you’ll be the savviest SPF wearer on the (sun) block.

Why is it important to wear sunscreen?

Firstly, I’m going to serve you some hard hitting facts. Did you know the sun causes 97% of all visible ageing in the skin? What’s more, people who use sunscreen with an SPF of 15 (or higher ideally) daily show 24 percent less skin ageing than those who don’t use sunscreen daily.

More importantly, these people are also 50% less likely to develop skin cancer melanomas. Alarmingly, a person’s risk for melanoma doubles if they have had more than five sunburns. And just one blistering sunburn in childhood or adolescence more than doubles a person’s chances of developing melanoma later in life. Yikes.

How does the sun damage your skin?

As you no doubt know, the sun emits UV radiation, along with infrared radiation and visible light.

UV rays can be divided into 3 types according to their energy, UVC, UVB and UVA. You might not have heard of UVC, but in fact it is the most harmful type of UV. But luckily, it’s also the least penetrating. UVC is almost completely blocked by the atmosphere and the ozone layer, so we don’t need to worry too much about it.

On the other hand, UVA and UVB rays you do need to worry about. These are the sun’s rays that cause skin burning, ageing and cancer.

What’s the difference between UVA & UBA?

UVB is the type of UV that you’ve probably heard about the most. UVB causes sunburn and can lead to deadly skin cancer and melanomas. On the positive side, it’s also the type of UV light that’s involved in the production of vitamin D in the skin.

While previously less famous than UVB, thanks to recent research we now know UVA penetrates deeper into your skin than UVB. And while the effects of UVA are less immediate (they don’t cause sunburn) they build up over time, which makes them arguably more dangerous.

UVA forms highly reactive free radicals in the skin, causing damage known as oxidative stress. This speeds up the ageing process and damages the structure and function of the skin. The result? Pigmentation, visible wrinkles, crepey, old-looking skin, inflammation, enlarged pores and textural issues.

One easy way to remember the difference between the two is to recall that UV ‘B’ rays cause burning, while UV ‘A’ rays cause ageing.

While another difference is that UVB rays are mostly blocked by regular window glass, UVA rays can penetrate glass. This means, even if you’re indoors you are not protected from sun damage.

I have a dark skin tone/tan well and never burn, do I still to apply sunscreen?

If you have dark skin tone or get a stunning mahogany tan during the summer, this means you have more melanin in your skin and therefore have greater natural protection from the sun.

However, while melanin acts to diffuse UVB rays and may protect against sunburns, people with darker skin should still use a full spectrum sunscreen. While you might not experience skin burning as easily, those pesky UVA rays are still going to town causing free radical damage and skin ageing.

While we’re on the topic, it’s helpful to know what a tan actually is. A tan is the body’s natural protective response to UV exposure. The browning of the skin that we see is actually an excess production of melanin that the body produces naturally in a bid to protect against UV damage. When exposed to too much UV light, the melanin leaks into the dermal tissue causing a tan. Not quite as sexy when you know the science is it?

However, melanin will not protect the skin from extreme sun exposure, such as spending long hours in the sun unprotected. Plus you’re still likely to get unsightly and dangerous pigmentation.

What type of protection should I look for on an sunscreen bottle?

Firstly, you’ll need to look at the sun protection factor (SPF). SPF is a measure of how long you can stay in the sun before UVB rays will burn your skin. According to the Skin Cancer Foundation, an SPF of 15 blocks 93% of UV rays; an SPF of 30 blocks 97%; and an SPF of 50 blocks 98% of UV rays.

That may seem like a small difference until you realise that the SPF 30 is allowing 50 percent more UV radiation onto your skin.

Next, 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.

To ensure you’re getting maximum protection it’s recommended that you apply a broad-spectrum sunscreen with an SPF of at least 30, ideally higher. So yes, this means that the SPF 15 contained with your moisturiser isn’t quite up to the job.

How much sunscreen do I need to apply?

The ‘Teaspoon and Shot Glass Rule’ recommends using one teaspoon of sunscreen to cover the face and neck, and enough sunscreen to fill a shot glass to cover all other exposed areas on the body.

Even if you’re a stickler for applying sunscreen every day, many people do not apply enough screen. In fact, very high SPFs often create a false sense of security.

People who use them tend to stay out in the sun much longer, and skip reapplying. And they may think they don’t need to seek shade, wear a hat or cover up with clothing. They end up getting a lot more UV damage, which, of course, defeats the purpose.

If the recommended amount seems like a lot, well, it is. However, to ensure you’re getting the level of protection as stated on the bottle this is how much you need to apply. If you’re applying less than this you’re getting less protection.

Do I need to reapply sunscreen during the day?

Many people think that sunscreen will last all day after just one application. In reality, sunscreen breaks down in the light and loses its effectiveness over a short period of time. As such, it’s recommended that you should apply sunscreen every 2 to 4 hours, at least.

This applies even if you coated yourself in a broad spectrum, SPF 50 sunscreen first thing in the morning. You’ll still need to top up during the day to maintain protection.

What’s more, this doubly applies if you’re going to be in water or sweating a lot during the say, say if you’re gardening, hiking or playing sport. Products can no longer advertise sunscreens as waterproof or sweat proof. Instead, you might see ‘water resistant,’ but this protection will last a maximum of 80 minutes.

If you’re wearing makeup, a top tip is to reapply with a beauty sponge. Gently tap the formula into the skin so you don’t disturb your makeup.

Do I only need to apply sunscreen on really sunny days or when I’m outdoors?

You might think that that sunscreen is not necessary on cloudy days. The truth is that even if it’s a rainy, cloudy, gloomy day, clouds only cover a small percentage for the sun’s UVA/UVB ray.

In fact, a massive 80% of UV rays pass right through the clouds. Thus, wearing sunscreen (as well as adhering to other protection measures, as detailed below) on any area of the body exposed to the sun 365 days of the year is important.

As mentioned, UV rays can penetrate glass so this means you’ll need to lather up even if you’re indoors and near a window, or driving.

Does sunscreen go off?

All makeup and skincare products have a shelf life. You can check the back of pack, where you’ll find an icon that looks like an opened tube. Next to it there’s an indication as to the period of time the product remains functional and safe after opening, usually six to twelve months.

While this is important to be mindful of for all beauty products, it should be adhered to strictly for sunscreen. The active ingredients can break down over time, and using expired sunblock may leave the skin unprotected.

Visible changes in colour or consistency can also indicate that it is time to dispose of the product. So, if you’re thinking of using last year’s SPF for your sun holiday this year, think again.

Are there other ways to protect skin from the sun?

While sunscreens play a critical role in reducing UV damage on the skin, they aren’t the only, or even the best sun protection. Many don’t have complete UVA protection, they need reapplying, and it’s really easy to miss a spot or apply too little.

Luckily, there are other options. Firstly, seek shade and avoid sun exposure at peak times. Secondly, and it seems obvious, physically block your skin from the sun with sun protective clothing, swimwear, hats and sunglasses. Hats are especially good for protecting your scalp – when was the last time you put SPF on your scalp?

Lastly, you can add UVA tints to windows that you go near frequently, such as at home or in your car. Many windshields are already designed to block UVA.

Should I avoid the sun at all costs?

At this point you might be asking, should I just cover myself head to toe and never let my skin see the sun? In fact, influencer Lauren Evarts Bosstick released a “skincare” book called ‘Get The Fuck Out of the Sun.’ Lauren’s mantra is part of a growing fear mongering narrative, particularly on social media, that the sun should be avoided at all costs to reduce UV damage.

However, I don’t suggest you get the f*uck out of the sun, entirely. Yes, you should obviously protect yourself from excess UV exposure, but avoiding it completely is bad (albeit very popular) advice.

The sun is essential for life. It’s our primary source of Vitamin D. It’s good for our immune systems and gut microbiomes. It triggers healthy pineal gland function, which regulates melatonin, which regulates sleep, which stimulates skin repair. Yes, you read that right, the sun can be good for the skin. It can help regulate sebum production and overall contributes to healthy, high-functioning skin.

– Godar DE, Urbach F, Gasparro FP, van der Leun JC. UV doses of young adults. Photochem Photobiol 2003; 77(4):453-7
– Taylor CR, Stern RS, Leyden JJ, Gilchrest BA. Photoaging/photodamage and photoprotection. J Am Acad Dermatol 1990; 22:1-15.
– Pfahlberg A, Kölmel KF, Gefeller O. Timing of excessive ultraviolet radiation and melanoma: epidemiology does not support the existence of a critical period of high susceptibility to solar ultraviolet radiation-induced melanoma. Br J Dermatol 2001; 144:3:471-475.


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