Anyone who has tried to choose a sunscreen knows that comparing the labels, ingredients, and formulations of the hundreds of options available can take hours. While many of the characteristics of your chosen sunscreen can be left to personal choice, there are two items you shouldn’t skimp on: an SPF of at least 30 and broad-spectrum protection.

But while most people appreciate the importance of SPF value, they may not understand that broad-spectrum coverage is equally important. So, what exactly does this mean, and why does it matter?

Sun damage accounts for up to 90% of all premature skin aging. But by following these tips, you can lessen the amount of damage caused by UV radiation and prevent your skin from looking and feeling older.

Firstly, why should we be careful?

Nobody wants to spend the entire summer indoors, and indeed some sunshine, below sunburn level, can be good for us, helping the body to create vitamin D and giving many of us a feeling of general wellbeing as we enjoy outdoor summer activities.

However, we often overexpose ourselves to the sun, which can result in a variety of skin problems, the most severe of which is skin cancer. Sunburn, photosensitive rashes, and prickly heat are some of the other summertime skin issues. Furthermore, sun exposure can aggravate pre-existing conditions such as rosacea.

While many people associate a tan with looking healthy, a tan is a sign that our skin has been harmed by UV radiation and is trying to defend itself against further damage. This kind of damage can in turn increase your risk of developing skin cancer: Sunburn (i.e. skin redness) and heavy tans can never be justified and are harmful.


Most people on the hunt for a sunscreen already know that the sun’s ultraviolet (UV) rays are harmful. But not all UV rays are created equal, and understanding how each type affects the skin can reveal why keeping all of them at bay is crucial. 

UV radiation from the sun is transmitted in three wavelengths – UVA, UVB and UVC. UVC does not penetrate the earth’s atmosphere, so we only really need to protect against UVA and UVB.

broad spectrum sunscreen

UV irradiation in the form of UVA is associated with skin ageing. UVA affects the elastin in the skin and leads to wrinkles and sun-induced skin ageing (for example coarse wrinkles, leathery skin and brown pigmentation), as well as skin cancer. UVA can penetrate window glass and penetrates the skin more deeply than UVB. UVA protection in sunscreen will help defend the skin against photo-ageing and potentially skin cancer.

UVB is the form of UV irradiation most responsible for sunburn and has strong links to malignant melanoma and basal cell carcinoma risk (types of skin cancer). A sunscreen with a high SPF (sun protection factor) will help block UVB rays and prevent the skin from burning, and by extension damage that can cause skin cancer.

HEV & IR-A Rays

You may have heard of UVA & UVB, but HEV and IR-A rays are something that also effect your skin.

High Energy Visible light (HEV), is blue light or near ultraviolet light, that you have more exposure to than you might realize.  Sources of HEV light include sun exposure, mobile devices, tablets, computer monitors, laptops, and full spectrum lighting.

There is emerging scientific evidence which shows that HEV light has the potential to cause long-term damage to skin cells in the epidermis and dermis. This has the knock-on effect of causing DNA damage within these cells and activating that break down fibres that give the skin support. Over time, this can result in fine lines, wrinkles, and premature ageing.

Research also suggests that more than half of the sun’s radiation is IR-A which results in an increase of free radicals which in turn causes DNA damage and prematurely ageing skin.

How do sunscreens work?

There are two main types of active ingredients in sunscreen: chemical (or organic) and physical (or inorganic). Although there are a few differences between them, they both work to reduce the impact that UV radiation has on your skin.

broad spectrum sunscreen

Organic filters absorb harmful UV radiation and convert and give this energy back out as infrared. These are sometimes known as ‘absorbers’, or ‘chemical’ sunscreens.

Inorganic filters (also known as ‘physical’, ‘natural’, ‘reflective’, ‘zinc’) contain titanium dioxide or zinc oxide, which reflect UV radiation away from the skin. Although these ingredients don’t irritate the skin as much as chemical ingredients, they are more likely to leave white residue — which is something to consider if you’ll be taking photos, for example.

What is SPF?

In the UK, sunscreens are labelled with a ‘SPF’. The SPF stands for ‘sun protection factor,’ but it is more accurately known as the sun burn protection factor because it primarily indicates the amount of UVB protection rather than UVA protection.

SPFs are rated on a scale of 2-50+ based on the level of protection they offer, with ratings between 2 to 14 forming the least protected end of the spectrum and ratings of 50+ offering the strongest forms of UVB protection.

UVA star system vs broad-spectrum

When you currently buy sunscreen containing UVA protection in the UK you may notice a UVA star rating on the packaging. The stars range from 0 to 5 and indicate the percentage of UVA radiation absorbed by the sunscreen in comparison to UVB, in other words the ratio between the level of protection afforded by the UVA protection and the UVB protection.

broad spectrum sunscreen

This rating system was introduced by a UK retailer as part of a marketing initiative and is applied to products from suncare companies that wish to sell their sunscreens within that retail store.  However, it is not part of any EU regulations or industry standard testing.

Therefore, if you choose a low SPF it may still have a high level of stars, not because it is providing lots of UVA protection, but because the ratio between the UVA and UVB protection is about the same. That’s why it’s important to choose a high SPF as well as a high UVA protection (e.g. a high number of stars).

Sunscreens that offer both UVA and UVB protection are sometimes called ‘broad spectrum’. A sunscreen with an SPF of 30 and a UVA rating of 4 or 5 stars is generally considered as a good standard of sun protection in addition to shade and clothing.

Choose a broad-spectrum sunscreen with SPF 30 or higher.

Look for items that are labeled “broad-spectrum” or explicitly claim that they protect against UVA and UVB radiation, as well as HEV rays. All sunscreens labeled “broad-spectrum” have passed the FDA’s broad-spectrum test; however, some countries do not have as stringent rules, so be cautious when purchasing sunscreens manufactured elsewhere.

A sunscreen with an SPF (Sun Protection Factor) of 30 to 50 will also provide you with better protection from the sun’s rays. Sunscreens with an SPF of more than 50 only offer a marginal improvement in sun safety, so it’s simpler to use sunscreen more efficiently rather than use sunscreens with a high SPF.

Don’t depend on skincare or makeup products that contain minimal SPF, either. Foundations or tinted moisturizers with SPF 15 do provide some measure of sun protection, but it’s not enough to adequately protect your skin from sun damage. It’s best to combine them with an actual sunscreen formulation with at least SPF 30.

Why we suggest using ZO Skin Health sunscreen.

Each sunscreen not only shields the skin against UVA, UVC and UVB radiation but also provide protection from blue light, (also known as HEV light) and IR-A rays.

ZO® sun protection portfolio offers both physical and chemical sunscreens that provide broad-spectrum protection against harmful, skin-aging UVA rays and skin-burning UVB rays. The physical sunscreens incorporate proven inorganic sunscreens, while our organic sunscreens incorporate a blend of safe chemical filters. Every ZO® sunscreen is oxybenzone-free.

All ZO sunscreens have been approved by the Skin Cancer Foundation Seal of Recommendation.

Our top sun safety tips

  • Protect the skin with clothing, including a hat, t-shirt and sunglasses
  • Spend time in the shade between 11am and 3pm when it’s sunny
  • Use a ‘high protection, broad spectrum’ sunscreen of at least SPF 30 which also has high UVA protection, and make sure you apply it generously and frequently when in the sun.
  • Keep babies and young children out of direct sunlight

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