Spotlight On: SPF

When should you apply sunscreen? How much should you apply? And how do you find the right one for your skin? We answer all of these questions, and more, here…

Applying an SPF isn’t just essential for reducing your risk of developing skin cancer –  the sun’s harmful rays are responsible for over 80% of all skin damage and ageing. 

The skin remembers every minute of sun exposure and the damage accumulates over time, impacting your skin in ways that you may not be aware of – from impairing the skin’s DNA to its collagen and elastin structure. UV exposure has also been linked to inflammation, oxidation, a thickening of the skin, a loss of firmness and natural radiance.

It’s also the leading cause, or exacerbates, many skin conditions, from rosacea and acne to hyperpigmentation. Finding the right SPF for your skin, applying it correctly and often enough is key to a healthy complexion. So what do you need to know about finding the right sunscreen? Let’s find out…

How does SPF work?

Sunscreens contain active ingredients that protect skin cells from the sun’s ultraviolet radiation, including UVB (the rays that cause burning) and UVA (the rays that cause skin ageing), in order to prevent skin damage that can lead to skin cancer as well as the signs of ageing. Sunscreens work by incorporating either chemical or physical active ingredients (or a combination of both) to protect skin against UV damage.

Chemical sunscreens are made with chemical active ingredients like avobenzone, octocrylene, octinoxate, homosalate, octisalate and propanediol, which work by absorbing UV light that comes into contact with the skin.

Physical sunscreens on the other hand, also known as mineral sunscreens, contain mineral active sunscreen ingredients like zinc oxide and titanium dioxide, which work by reflecting UV light off of skin. Some SPF formulas include both chemical and physical sunscreen active ingredients.

What does SPF stand for?

‘SPF’ stands for Sun Protection Factor and is followed by a number (i.e. 15, 30, 50, etc) that indicates how long it would take the sun’s UVB rays to burn skin when the product is applied as directed on the label, versus how long it would take skin to burn without any SPF. For example, an SPF 50 indicates it would take 50 times longer for skin to burn during sun exposure when wearing the product than when not wearing SPF. 

The SPF number refers only to the protection provided against UVB rays, so look for the term “broad spectrum” on packaging to ensure the product also protects against UVA rays – these are the rays that penetrate most deeply into the skin, also known as the ‘ageing ray’.

When should you apply SPF? 

To understand how to correctly apply SPF, first, we need to address a few myths surrounding sunscreen usage.

Myth #1: You don’t need to use sunscreen on cloudy, rainy days. 

The fact is that UV rays penetrate on cloudy days too, so sunscreen is required for all 365 days of the year, and it’s non-negotiable. It’s also likely you’ll be on a screen at some stage most days, so protection from the HEV (High Energy Visible) light that screens emit is key as this can be just as damaging to the skin as UV rays. It’s a good idea to look for SPFs that protect against this type of light, too – check out my recommendations at the end of this blog post!

Myth #2: Applying sunscreen in the morning before going out in the sun is enough for the whole day

That’s nowhere near enough! You need to apply your SPF 15 minutes before sun exposure and then re-apply at least every two hours when in the sun for complete protection. If you’re sweating or you take a swim, you’ll need to reapply. Remember that even waterproof sunscreens will be removed when you rub yourself down with a towel.

Myth #3: Sunscreen means 100 percent protection.

Whilst sunscreen does protect you against UVA and UVB rays, it’s best to have other forms of protection too. Use wide-brimmed hats, super-sized sunglasses and protective clothing when you are going to be out in the sun for hours. 

Sunglasses are particularly important because when our eyes detect UV exposure, they tell the melanocytes (the pigment-producing cells) in our skin to put up their sun umbrellas to protect your cells, often causing irregular pigmentation.

Myth #4: You don’t need to wear sunscreen if you’re staying inside

If there is daylight bouncing around the room, those are UV rays and your skin still needs protecting. You also need to protect your skin from HEV light (that’s the High Energy Visible light emitted by your devices, which can be just as damaging to the skin as UV rays). 

So how should you integrate SPF into your day-to-day regime? Here’s our advice:

  • Always apply your SPF in the morning as final step in your skincare regime
  • You can top up during the day with an SPF spray or powder if wearing make-up
  • Don’t forget your eyes and lips. You can apply SPF to the eyelids, but if it’s irritating, then look for an SPF eye product
  • Remove your SPF last thing at night when you’ve finished using any devices

If you’re concerned with hyperpigmentation, then it’s important to be extremely strict with applying SPF, and reapplying it. Even going out in the sun for a few minutes without protection is enough to activate the easily excitable melanocytes, which create more pigment. This can undo any progress you may have made with treatments and skincare. 

How much sunscreen should you apply?

For lotions in a tube, you need one finger size worth of sun cream for your face and neck and two fingers for each body part, doubled for the backs of areas, again. It can be hard to judge if you’ve applied enough when using a spray for the body, so be generous – there’s no harm in applying extra sunscreen, so if you’re unsure whether or not you’re adequately protected, just apply some more.

What factor SPF do I need?

When choosing sun cream, the higher the SPF, the better the protection from UVB. Although a sun cream may block UVB and stop you burning, it may not block UVA – often referred to as UV Ageing – as these longer wavelengths penetrate deeper into the skin, damaging our collagen and causing fine lines, hyperpigmentation, uneven skin texture, large pores, a loss of elasticity and a coarse skin texture. So broad-spectrum sunscreen should protect against both. 

Most of us are pretty good at applying SPF on a beach holiday. The problem is the everyday, half an hour out walking at lunchtime that builds up over the years. We usually recommend an SPF50, which offers 95 per cent protection from UV as opposed to SPF30’s 93 per cent (a two percent difference which, over time, stacks up). Most of us underestimate how much sunscreen we need to apply to properly protect ourselves – wearing a higher factor SPF also helps to mitigate this risk.

Is SPF in make-up enough?

It’s a very common misconception that the SPF in your make-up will do the job, but sadly this isn’t the case. If you have a tinted moisturiser with SPF15, that’s only giving you a little bit of UVB protection. It’s also unlikely that you’ll apply enough tinted moisturiser to every area of your skin to offer that level of protection, so a dedicated SPF is key.

How do I choose the right SPF?

Repeatedly applying the wrong type of SPF can lead to breakouts, which is why it’s important to use the correct one for your skin. What’s more, sunscreen is only part of the equation when it comes to protecting the skin from the environment and the sun’s UV rays. Pairing the right sunscreen with the right antioxidants is key in order to effectively protect the skin against sunburn, DNA damage and oxidation. 

That’s because your genetic make-up also substantially affects how your skin reacts to, and protects itself from UV damage. When creating bespoke skincare regimes for our clients, we analyse their melanin production factors, their skin’s ability to repair itself from UV damage and their natural antioxidant levels. From this information, we can then tailor a regime in a way that more effectively protects them from further UV damage, whilst also repairing historical damage. 

Which SPFs are right for you?

Here are some of our top SPF picks for different skin types; but bear in mind that a thorough consultation is recommended to ensure that you are using the correct SPF for your skin. 

ZO Skin Health Gel Sunscreen Broad Spectrum SPF50 

An unscented clear gel with a complexion-smoothing finish for all skin types. It’s also water and sweat resistant for 40 minutes.
Great for: Anyone who loves swimming and watersports on holiday, or men looking for an SPF that won’t leave a white cast in their beards!

ZO Skin Health Sheer Fluid Broad Spectrum SPF50

A weightless mineral base with a natural bare-face finish for all skin types.
Great for: Oily and acne-prone skin. It’s also great to use as a make-up base, especially on those hot days when the skin is oilier or sweaty.


Colorescience Sunforgettable Total Protection Sheer Matte Sunscreen Brush SPF30

This weightless, untinted sheer powder absorbs excess oil and minimises the appearance of pores in one convenient, on-the-go application.
Great for: Keeping in your handbag and re-applying over make-up.


Hydropeptide Solar Defense Non-Tinted SPF50 

This SPF offers mineral protection that will protect from UVA, UVB and infrared rays while enriching the skin with hyaluronic acid to lock in moisture.
Great for: Sensitive skin, or those with particularly dry or eczema-prone skin.


ZO Skin Health Sunscreen Primer SPF30

This sunscreen protects from UVA/UVB and infrared rays, as well as HEV light. It hydrates and doubles up as a make-up primer for a smooth, matte finish that diminishes skin imperfections.  
Great for: Great for fair skin, or if you have rosacea to blur redness on the cheeks.


ZO Skin Health Smart Tone Broad Spectrum SPF50

A lightweight sunscreen with a self-adjusting tint that complements most skin tones while providing a healthy, hydrated glow. It’s rich in antioxidants while protecting against the ageing effects of UVA/UVB, infrared rays and HEV light. 
Great for: A foundation replacement – it doesn’t cover, but blurs imperfections.

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