Understanding Sunscreens

It’s no secret that SPF is a vital product in many antiageing regimes. With so many ingredients, factors and types on the market it can be difficult to get to grips with exactly which SPF would be most beneficial for yourself and patients. Products with varying star ratings, SPF values, and references to the words mineral, zinc oxide, organic and natural are often attached to SPF advertisements with little guidance on what they actually mean, the protection they offer, or any helpful information on their safety for use.

Misinformation about sunscreen is common, and so it is important to ensure myths or lack of understanding do not deter you from guaranteeing patients protect their skin. 

Defining SPF

SPF stands for ‘sun protection factor’ and refers to the amount of defence the sun protection sunscreen offers compared to unprotected skin. SPF 50+ is formulated to allow less damaging rays to reach the skin’s surface and therefore provide optimum protection.1 The lower down the numerical rating SPF products appear, as you would expect, the less protection they provide. Interestingly, from factor 15 to 50 there is only a 5% difference in the amount of UVB rays that are blocked, with SPF 15 blocking 93% of UVB rays, SPF 30 blocking 97%, and SPF 50 blocking 98%.1 

Rising cancer rates and why selection matters

With the Food and Drug Administration (FDA) having removed 14 of the 16 chemicals found in sunscreens from its ‘generally accepted as safe and effective category’2 in 2019, there has never been a better time to raise awareness on the types of SPF products which are safe to use. The FDA reported that of the 16 chemicals utilised, only zinc oxide and titanium dioxide are generally regarded as safe and effective.2 In the UK and the EU, sun protection products are defined as cosmetic products and are governed by the Cosmetics Regulation. In the US, the FDA governs the safety of these products.3

According to data from The Royal Marsden NHS, over 15,000 people each year in the UK are diagnosed with melanoma, with rates of malignant melanoma rising faster than any other cancer.4 Data from The British Skin Foundation indicated there were 14,000 new cases of melanoma and 147,000 cases of non-melanoma skin cancers reported in 2017. These types of skin cancer can be contracted through exposure to the sun’s rays, which comprise ultraviolet radiation in both UVA and UVB sunbeams.5

According to research from Cancer Research UK, within the last decade melanoma skin cancer rates have increased by 32%, with incidences in females doubling, and in males almost tripling.5

In light of shocking statistics such as these, it’s increasingly important for patients to be fully informed about the different rays which cause harm, and the products which can give them what they need in terms of protection and skin health. 

Shielding the sun’s rays

The three types of rays emitted by the sun include ultraviolet A (UVA) ultraviolet B (UVB) and ultraviolet C (UVC) as shown in Figure 1. UVC is the shortest wavelength and most damaging ray, however it does not reach the earth’s surface and is filtered by the atmosphere, so therefore is not something we need to concern ourselves with here.6 UVA is the ray which penetrates the skin most deeply due to its longer wavelength. Exposure to UVA rays result in premature skin ageing and pigmentation. UVB causes burning and reddening of the skin. UVB is the ray most commonly linked to causing cancer, however information from the Skin Cancer Foundation states that unprotected exposure to both UVA and UVB damages the DNA in skin cells and can lead to skin cancer.6

Patients need to understand that SPF values only relate to their capacity to protect skin from the sun’s UVB rays and not UVA. From this perspective, any product, whether medically graded or not, cannot entirely protect skin from the damaging impact of the sun’s rays and it is important to limit time spent in direct sunlight and wear other protective items such as sunglasses, clothing and sun hats and to seek shade.

Practitioner recommendations therefore need to encompass not just product and application suggestions, but also common-sense guidance that can debunk misconceptions around ensuring coverage and protection. Star ratings relate to the amount of UVA rays that sun protection products can block and range from 0 to 5. It is commonly understood that any product below 4 stars is not suitable in its capacity to protect the skin, as per advice from The British Skin Foundation.7 

Chemicals vs mineral sunscreens

When recommending different SPF products to patients, practitioners can explore the differences between chemical and physical sunscreens.

Chemical sunscreens known as organic or synthetic sunscreens are the most commonly used and recommended by The British Skin Foundation.7 They work through absorption of UV light and the release of it in heat form. Oxybenxone, avobenzone, octisalate, octocrylene, homosalate and octinoxate are the chemicals, amongst others, that will be found in this category of sunscreen.8

According to the Skin Cancer Foundation sunscreen needs to be applied to skin 30 minutes before sun exposure9 and is usually more popular with patients due to their typically thinner texture and easier-to-spread consistency. However, it may be less widely understood that due to the chemical composition of these types of sunscreens they can be ‘used’ up more quickly when in direct sun,7 and can require more regular application. They may also be more likely to cause skin irritation, due to the combination of ingredients and UV light. This irritation is referred to as ‘irritant contact dermatitis’ by The Cancer Council and is more common in those with sensitive skin10 or with a history of eczema. Patients should be aware of all the ingredients before application, so as to check for any contained fragrance or preservatives that they may be allergic to.

As many people under-apply their sun protection, it is important to offer guidance as to the amount required to ensure proper shielding from UV rays. A minimum of 2mg to every cm2 of skin should be applied, instead of the usual quarter or half of this amount that most people tend to apply.11

Mineral sunscreen, also referred to as physical sunscreens, work by absorbing and then scattering or deflecting the UV radiation, whilst also absorbing the UV light and releasing it as heat. Titanium dioxide and zinc oxide are the two main chemicals used in these products.12

Mineral sunscreens are quicker acting than chemical sunscreens, as they provide protection from the sun immediately after they have been applied. They also tend to last longer in the sun, but are washed off when they come into contact with sweat and water which is an important detail for patients to understand, as this factor alone will impact the amount of application required. With this in mind, larger amounts are often required to achieve adequate protection.13

Mineral products are less irritant on the skin than chemical sunscreens because they reduce the likelihood of long-term exposure to chemical ingredients. It is worth noting that mineral products often leave a whitish cast on the skin, and therefore are less cosmetically acceptable for people with darker skin tones.14

Although there are sunscreen products available which combine both mineral and chemical ingredients, research shows that mixing the two can lead to degradation of the sunscreen or sun block and hinder the product’s effectiveness. As a result, I only recommend usage of the mineral-based products.15

Product selection and daily habits

When recommending best practice to patients, medical practitioners should be advising, in line with the FDA and British Skin Foundation guidance that sunscreens or skincare products of at least SPF 15 and upwards need to be applied to ensure skin protection.6

Like many aspects of the aesthetic industry, consistency is key. A broad spectrum SPF should be applied as part of the daily morning skin routine. Broad spectrum SPF refers to sunscreen which offers protection against both UVA and UVB rays, safeguarding both the skin’s surface and deeper skin tissue when applied.6 This ensures the skin is protected from the get go, and also offers a way for patients to incorporate skin health and protection into their daily routine. As not all sunscreens are broad spectrum, this can be another area of patient confusion. In terms of transparency, medical practitioners should be informing their patients that sunscreens which are broad spectrum, or are below SPF 15, are meant to contain warning labels on the products denoting the dangers of skin cancer and skin ageing via a clear ‘alert’ label.16 Checking products for these warning labels, however small, is a good way to assess their suitability before purchasing for your clinic and recommending to patients.

There are many different brands of sunscreens available and many are produced by high-quality cosmeceutical brands and pharmaceutical companies. In my clinic, I choose to recommend Heliocare 360° broad spectrum SPF and ZO Skin Health Smart Tone SPF 50.

Heliocare 360° is extensively studied, with more than 50 studies published in leading international medical journals. Evidence demonstrates that it is not only effective in photoprotection, but also for the prevention of skin ageing, actinic damage, sun allergies and dark spots. The Gel Oil-Free SPF is suitable for all skin types, including sensitive skin, and a great option for skin of colour due to its clear, barely there, matte finish, which my patients appreciate.17

I recommend the ZO Skin Health Smart Tone SPF 50 to patients who like a tinted SPF that blends into their natural skin tone and combats against the appearance of redness. I have found this is a particular favourite amongst patients who have rosacea skin concerns. This is due to its capacity to minimise redness, guard against the appearance of photodamage, and its 12-hour antioxidant time release which keeps the skin hydrated.18

Awareness is key

As responsible aesthetic practitioners we need to firstly understand the science of sun protection, and inform our patients about the best ways to research, purchase and apply sunscreen products. Raising awareness and being transparent is the best way to help patients protect themselves from the harm caused by sun exposure. Providing valuable, honest information ensures practitioners are the voices which our patients can trust, and establishes us as individuals who can help our community maintain youthful and healthy skin in the long term. 


1. Which sunscreen should I use? (2018). Medical News Today.

2. Food and Drug Administration, Sunscreen - How to Help Protect Your Skin From The Sun: USA, 2022,

3. GOV, Guide to Cosmetic Products, 2013, <>

4. Royal Marsden, Skin Cancer Incidence, <>

5. Cancer Research UK, Melanoma Skin Cancer Statistics: UK, 2018, <>

6. Anna Chein, UV radiation risks, 2021, <>

7. Adil Sheraz, Sunscreen Explained, 2020, <>

8. EWG, The Trouble With Sunscreens, 2020, <>

9. Skin Cancer Foundation, All About Sunscreen, 2021, <>

10. Cancer Council, Sunscreen Reactions, <>

11. FDA, Stay Safe in Sunscreen, 2021, <,sunscreen%20completely%20blocks%20UV%20radiation>

12. FDA, New Proposed Regulation, 2019, <>

13. Lauren Bedosky, Chemical vs Mineral Sunscreen, 2021, <>

14. Meagan Drillinger, Mixing Chemical and Physical Sunscreens, 2021, <>

15. FDA, Questions and Answers, 2014, <,A.,%5D%22%20on%20the%20front%20label>

16. Cantabrialabs, Heliocare: UK, <>

17. ZO Skin Health, Smart Tone Broad Spectrum SPF, <>

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