The sun's rays can be glorious and many of us love to spend time in the sun. In fact, if we enjoy the sun in reasonable amounts, they can provide us with many good health benefits. However, overexposure to UV rays can lead to discomforts such as painful, red and inflamed skin but also cause longer-term effects such as premature ageing of the skin with deep wrinkles and pigmentation spots or, in the worst cases, various forms of skin cancer. To protect yourself from the sun's harmful rays, try to minimise the time you spend outdoors when the sun is at its highest, wear a protective layer of clothing, a sun hat and apply sunscreen to the skin that is exposed. And those - the sunscreens - are what we're going to dive into now!

The harmful UV radiation

When we think of sunbathing, our thoughts often drift to a wonderful day at the beach, but as you know, the sun's rays are far from healthy. Solar rays contain different types of radiation with different wavelengths, including the harmful UV rays. Ultraviolet (UV) radiation is invisible to the human eye and comes in different varieties - UVA which has the longest wavelengths (320-400 nm) and the least energy, UVB (290-320 nm) which is in between and UVC which has the shortest wavelengths (below 290 nm) and the highest energy. The Earth's ozone layer helps and protects us from all the sun's UVC rays, while UVB rays penetrate the outermost layer of the skin and stimulate melanocytes to produce more pigment. UVB rays are also linked to DNA damage and skin cancers such as malignant melanoma. UVA radiation reaches even deeper into the skin layers and can cause premature ageing such as fine lines, wrinkles, dilated blood vessels and spider veins.

Important information:

UVB penetrates the epidermis but not the dermis and does not go through a glass window.

UVA penetrates deeper into the skin and the radiation penetrates the dermis. It also goes through a glass window.

UV index - tells us how dangerous the sun's rays are 

The UV index is an international standard used to measure the intensity - and therefore the harmfulness - of the sun's UV rays. Using it, we can compare how intense the UV rays are in different places and at different times of the day. The higher the index value, the stronger the UV radiation you are exposed to. An illustration of the UV index in Figure 1 shows what the UV index normally looks like in Sweden.

In Scandinavian countries, the UV index is usually between 4 - 7 during the summer season and between 0-2 during the winter, this could explain our longing for the sun every spring! At a low UV index you don't need to use sunscreen, but at a high UV index where the radiation is more intense you need to protect yourself, because a high UV index increases the risk of negative effects.

It is important to protect yourself from both UVA and UVB rays, so a good sunscreen should provide protection from both. The Sun Protection Factor (SPF) mainly describes the product's protection against the sun's UVB radiation, with a higher SPF providing better protection. The highest SPF you will see on a sunscreen product is SPF 50+ which means very high protection. Products labelled with a UVA symbol (the letters UVA surrounded by a ring) mean that they provide sufficient protection against the sun's UVA rays. To get the protection promised on the packaging, you need to apply the product in an even and thick layer. To maintain good protection, reapply the sunscreen at regular intervals, especially if you have been swimming or exercising. However, creating a product that provides protection after swimming and exercising is a challenge because it requires the product to be water-resistant while not feeling too sticky to wear on the skin. 

(Example of a typical summer day in Scandinavian countries) 

How does sunscreen work?

Sunscreens contain active ingredients called UV filters. These substances protect the skin by absorbing and reflecting harmful UV rays from the sun. To achieve effective and balanced protection against UV radiation, a combination of different UV filters must be used. Sunscreen products must contain only specified active ingredients and only in authorised quantities. These substances are listed in regulations and are regulated by authorities such as the Medical Products Agency in Sweden, the FDA in the US and the CFDA in China. Developing and manufacturing sunscreen products that meet all these requirements, provide good, broad-spectrum protection and also feel comfortable on the skin is a complex and costly process.

The protective UV filters used in sunscreens work by either absorbing or reflecting the sun's UV rays - or a combination of both. In this way, they reduce the amount of harmful UV radiation that penetrates the skin and affects the body's cells. Therefore, sunscreens must remain on the skin's surface to be effective.

When talking about UV filters, they are usually divided into organic filters and mineral filters. The difference between the two forms is mainly that organic filters are soluble in the product, while mineral filters remain as particles. Another difference is also what they are made of, organic filters are organic (based on carbon) molecules while minerals are as the word reveals - mineral based. However, this is not entirely true, as some new and modern organic filters are also particles and can therefore be seen as mineral filters. Different UV filters have different properties and differ both in effectiveness and in how they affect the skin, and it is important to make a careful choice when developing sunscreen. 

Organic filters

Most UV filters approved and used in sunscreens are organic filters in the form of either powders or oils. For powder filters to be effective, they must be dissolved in oils and fats. The higher the SPF, the more UV filters have to be used and the correspondingly more and higher contents of oils for the powder to dissolve in the formulation. The higher concentrations can make the product feel more greasy or sticky to apply, especially on a hot and sweaty day.

Some organic filters are linked to endocrine disrupting effects.

"An endocrine disruptor is a substance that alters the function(s) of the endocrine system, thereby causing adverse health effects"

Mainly benzophenones (i.e. oxybenzone), camphor derivatives and cinnamate derivatives are linked to endocrine disrupting effects. These UV filters are generally involved in the disruption of the hypothalamic-pituitary-gonadal system. Exposure to these chemicals has been shown to induce endocrine disrupting effects such as oestrogen-like or androgen-like effects in animal and cell studies. The potential for endocrine disruption is shown in Table 1.

Some organic filters are also contradictorily sensitive to UV light. This means that they can degrade in the presence of sunlight, reducing their sun protection properties. In addition, in some cases, harmful substances can be formed that can cause allergies or other undesirable side effects. Some organic UV filters are suspected, or have been shown in models, to interfere with hormones. The most skin-friendly and effective organic UV filters have a high molecular weight, which means that they do not penetrate the skin. It is therefore of utmost importance to carefully select UV filters and ingredients when formulating a good sunscreen product.  

Now let's delve into the organic UV filters. For a consumer, it can be difficult to read and understand the ingredients list and the filters used in the product because the filters have complex names. In addition, the use and names of the filters can vary in different parts of the world. Many of the more recently developed and better organic UV filters are restricted for use in the US, which means that the US market uses many filters that have been phased out in Europe and most of the world, due to safety concerns.

Organic UVB filters

Aminobenzoates var bland de första UV-filtren som användes men har mer eller mindre fasats ut i Europa. Filtret absorberar UVB men kan inte absorbera UVA. PEG-25 PABA är ett effektivt UVB-filter; det rapporterades dock, tillsammans med Benzophenone-3, som det allra vanligaste fotoallergenet och kontaktallergenet.

Cinnamates replaced or supplemented PABA and are a potent UVB filter and include Ethylhexyl Methoxycinnamate and Isoamyl p-Methoxycinnamate. Ethylhexyl Methoxycinnamate is the most widely used UVB filter in the US and is still widely used in Europe; however, Ethylhexyl Methoxycinnamate is not very photostable and degrades after a short time in the presence of sunlight, especially in combination with the UVA filter Butyl Methoxydibenzoylmethane. Ethylhexyl Methoxycinnamate is also considered to be an endocrine disruptor and has a negative environmental impact. 

Salicylates are weaker UVB absorbers and therefore provide a lower increase in protection per amount added. They are also used to dissolve other UV filters, thereby increasing the protective effect. Examples of these are Homosalate and ethylhexyl Salicylate. This group of substances is suspected to have endocrine disrupting effects and is now being investigated in this respect.

Octocrylene is a very common organic filter and a relatively weak UVB absorber. The filter has a widespread use but has been associated with phototoxicity and photoallergic potential. It is also considered an environmental pollutant and can cause coral bleaching.

 Phenylbenzimidazole is a UVB filter that is a water-soluble compound typically used in products where you want a lighter, less greasy feel and where water resistance is not critical. Although the substance has been reported to cause photoallergy, it is considered to have a low risk of causing sensitization.

Ethylhexyl Triazone och Diethylhexyl Butamido Triazone är moderna mycket effektiva UVB-filter med en stor molekylstorlek. På grund av storleken kan de inte tränga in i huden och är därför inte förknippade med hudallergi, hudreaktioner eller em endokrin effekt. De är godkända i EU men för närvarande inte i USA. Används i Skinomes Sun Emulsion SPF 30 och 50+.

Broad spectrum organic UVA and UVB filters

Benzophenones mostly absorb UVB. However, Bensophenone-3 is considered a broad-spectrum filter as it also absorbs UVA. However, of all UV filters, Bensophenone-3 is most likely to cause contact or photocontact dermatitis and has therefore been largely phased out.

Bis-Ethylhexyloxyphenol Metoxifenyltriazin är ett modernt UV-filter som ger ett bredspektrumskydd och absorberar bra i både UVA- och UVB-området. Ämnet har en stor molekylstorlek och är inte associerad med allergier, en endokrin effekt eller hudreaktioner. Används i Skinomes Sun Emulsion SPF 30 och SPF 50+. 

Methylene Bis-Benzotriazolyl Tetramethylbutylphenol (nano) is an organic particle filter that absorbs well in both UVA and UVB. Similar to titanium dioxide and zinc oxide, it will produce a white film when used in the product and applied to the skin. It has been associated with some skin reactions, but this may also be related to the additives used in the raw material. 

Drometrizole Trisiloxane has a more limited use in specific brands. It has a larger molecule size and therefore stays on top of the skin and offers a limited risk of penetration and thus less risk of causing various skin reactions.

Organic UVA Filters

Butyl Methoxydibenzoylmethane has historically been the most widely used UVA filter. However, it is very photoinstable, especially when used with cinnamates, which is also why its efficacy decreases in contact with sunlight.

Terephthalylidene Dicamphor Sulfonic Acid och Disodium Phenyl Dibenzimidazole är fotostabila ämnen med större molekylstorlek och även hydrofila och håller sig därför ovanpå huden med begränsad risk för penetration.

Diethylamino Hydroxybenzoyl Hexyl Benzoate är ett fotostabilt modernt UVA-filter som har ersatt Butyl Methoxydibenzoylmethane som det huvudsakliga organiska UVA-filtret. Detta filter har inga rapporterade allergier eller endokrina effekter och anses därför vara allergivänligt. Används i Skinomes Sun Emulsion SPF 30 och SPF 50+.

Mineralfilter

Summary of UV filters in use today

Vi har sammanfattat de vanligaste UV-filtren som används i solskyddsmedel i vår tabell under Ämnen att hålla koll på i solskyddsprodukter.

How to choose the right sunscreen and how to use it

When it comes to choosing a sunscreen product, there are countless options. To minimise the risks of being in the sun and to reduce the use of sunscreen, the best way is to dress properly and avoid the sun when it's high in the sky. Nevertheless, it is also important to regularly apply a sunscreen to the areas exposed. Ideally, choose a product that protects against both UVA and UVB rays and provides high or very high protection. By choosing products that are fragrance-free, you are doing yourself and your skin a favour, as fragrances are among the most allergenic substances used in cosmetic products, an effect that can even be exacerbated by sunlight. To find the right product for you, it's worth considering:

• What type of skin you have. Fair-skinned and red-haired people need to protect themselves more to avoid getting burnt. 

• Hur ljus och stark solen är. Kontrollera hur högt UV indexet är i ditt område.

• That your sunscreen gives you the right protection. Choose a product with a UVA symbol to ensure you're getting good, broad-spectrum protection. 

• Choose a photo-stable product that doesn't lose its power when you stay in the sun.  

• Sunscreen products with both mineral filters and new modern organic UV filters are best to ensure good protection from the sun.  

För att få bästa möjliga solskydd bör du använda minst lika mycket av produkten som tillverkaren rekommenderar, eftersom det är den mängd som har använts vid testning av produkten. En persons hudyta uppskattas vanligtvis till cirka två kvadratmeter och mängden produkt som används i SPF-testerna är två milligram per kvadratcentimeter. Detta motsvarar cirka en kupad han för en vuxen kropp, vilket är mer än vad de flesta använder när de applicerar solskyddsmedel. En vanlig standard som används för att få tillräckligt med kräm är att applicera mängden som ryms i en kupad hand på hela kroppen. Om du använder spray eller mousse är det mycket svårare att förstå hur mycket som behövs, eftersom det inte går att kvantifiera på samma sätt. Dessutom är det bäst att applicera en mindre mängd på en kroppsdel i taget för att få en så smidig och jämn applicering som möjligt.

Låter det krångligt att välja rätt? Vi har redan tänkt på allt detta i utvecklingen av våra produkter. För ett säkert, högpresterande solskydd- välj Skinome Sun Emulsion SPF 30 eller SPF 50+.