How to choose sunscreens

Phototype, SPF, filters: find out what they are and how to stay in the sun while keeping your skin safe.

Basking in the sun? Be safe with the proper sun protection.

Basking in the sun is nice, is good for your health and also puts you in a good mood.

However, when we plan to stay in the sun, it is important to protect skin, even if our skin is dark or we don’t intend to stay in the sun for too long. Sun protection is indispensable for everyone because the effects of sun radiation on skin can be very damaging both in the short term and, especially, in the long term, with delayed effects that can occur even after years.

How do we know what sunscreen best suits our skin type?  

Here is what you need to know to enjoy the sun safely.

The phototype

A phototype is a set of individual physical characteristics (ethnicity, eye and hair colour, how easily your skin gets darker) that changes according to the amount o f melanin in our skin. Having a particular phototype (I to IV) means having less or more melanin, thus less or more physiological protection against sun rays.

Generally, there are six phototypes (based on the Fitzpatrick classification), each described with the characteristics and reactions to the sun shown in the following chart.

The lower the phototype, the higher the risk of a reaction, hence the higher the protection must be. Similarily, if the phototype is high, the amount of melanin made by skin is larger, hence skin is naturally more protected and one can pick a lower-spf sunscreen.

Knowing your exact SPF is not indispensable

Usually, the fairer your skin is, the more chances you have to get sunburn, though it doesn’t work that way all the time. Even a person with dark hair and eyes can easily get sunburn and, conversely, someone with fairer skin and eyes might as well react less to the sun. 

The most important thing for choosing the sunscreen that best suits us is to know how our skin reacts to the sun. If you tend to get sunburn quite easily, the protection that suits you is either high or very high, while if you get sunburn rarely, or you never do, you can pick a medium or low protection.  

The sun protection factor

Sun protection factor packaging bears the abbreviation SPF followed by a number: this is the sun protection factor. TO be precise, SPF would actually mean Sunburn Protection Factor, since the number tells the protection a sunscreen offers to delay sunburn, or solar erythema, as it should more properly be called.

The term “solar erythema” means skin redness induced by the sun and should not be confused with a type of reaction to the sun that shows with reddened bumps and itch on skin and that everyone calls erythema, but is actually photodermatitis (polymorphous light eruption).

The sun protection factor is determined by a method which has been verified and validated by the European Commission and is therefore the "official" method (International Standard Method ISO 24444:2010). The method is performed on volunteers (in vivo) and it "simulates" what occurs to skin exposed to the sun, with sunlight being replaced by a source of energy that replicates it (solar simulator). The test measures the time it takes for erythema to show on both unprotected skin and skin protected with a pre-set amount of product (2 mg / cm2).

Data is then statistically processed to identify the average SPF value. The higher the SPF is and the stronger the ability of the product to delay erythema.

However, there is a limit to the protection that a sunscreen product can provide, meaning that is is important to bear in mind that no product can guarantee full protection against the risks UV rays may trigger.

This particular aspect, as well as many others concerning the importance of sun protection products as means to protect people's health, has been dealt with by the European Commission with Recommendation No. 2006/647/EC (link

(inseriamo il link a questo documento anche tra i link esterni di approfondimento in spalla sinistra)

With the aim to provide simple indications and eliminate the multiple numbers used to identify SPF values, the European Commission recommends to adopt labelling that matches protection levels to numerical values:

The recommendation indicates 50+ as the maximum SPF, besides recommending that there should be no indication that might mislead the end-user into thinking that a sunscreen can provide 100% protectiuon from UV radiation.

Broad-spectrum protection

Since solar erythema (sunburn) is induced by UVB rays, the indication on the package refers to the protection against these rays only, yet a sunscreen must also protect against UVA rays, which are also involved in causing skin damage. Hence, a sunscreen must also contain UVA filters, so to offer broad-spectrum protection.

Also UVA protection is determined experimentally by an official method, that is a test all sunscreen manufacturers should use, but, unlike UVB protection, this test is performed in vitro (International Standard Method ISO 24443:2012).

How much should a sunscreen protect from UVA radiation?

Based on scientific data available, protection against UVA should be at least 1/3 of the SPF value. If the sunscreen meets this requirement, it bears a symbol on the pacjkage to say it, which is the encircled UVA logo:

How do sun filters work?

Sun filters, as the term implies, filter sunlight, thus block out UVA or UVB radiation, according to these mechanism:

  • sun radiation abrorption, typical of organic (chemical) filters, through ingredients that absorb the energy of the radiation
  • sun radiation reflection/scattering, typical of mineral (physical) filters (e.g. titanium dioxide), where filters work as mirrors to block sun rays out.

Sun filters are ingredients that are regulated by the European Union, hence a certain number of filters are allowed in sunscreens, and only at precise concentrations (ref. Regulation (EC) No. 1223 / 2009, Annex VI).

The broad-spectrum sun protection involves the combined use of both UVA and UVB filters, generally with a prevalence of organic type filters because the only authorized mineral filter, titanium dioxide, is rarely used alone. Why is that?

Being a white powder (it is also a pigment used in makeup products), titanium dioxide turns a sunscreen thicker and, if included in large amounts, leaves a white cast over skin upon application.

All authorised filters are safe for use, however some of the organic type may be less tolerated by skin in case of skin hyper-reactivity.

For this reason, mineral filter-only sunscreens may be more suitable for  skin types requiring special care.

Besides sun filters, other ingredients are necessary in sunscreens, for instance to make the sunscreen pleasant to apply, to ensure photostability and resistance to water.

Moreover, today research and development looks at formulating sunscreens that, while protecting from the immediate damage sun radiation can cause, will also defend from long-term, delayed damage.

However, effectiveness of sunscreens is achieved especially if we follow a few simple rules on how to use them properly.

Learn more by reading this article: Sunscreens: how much is needed, how to apply and how frequently?


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All BioNike products of the TRIDERM, DEFENCE and PROXERA ranges are developed to reduce the risks of intolerance and are suitable for sensitive skin. Such products are, in fact nickel-tested, preservatives-free, perfume-free (or having an allergen-free perfume), gluten-free and manufactured ​​with carefully selected and controlled ingredients.

In any case, we recommend that you consult your pharmacist and/or dermatologist, who will be able to recommend what is best for your skin.

Did you know it?

The BioNike laboratories have developed Defence Sun, a sun protection range for babies and children that provides triple photoprotection:

  • defence against short-term damage through the UVA-UVB filter system
  • defence against free radicals generated by infrared IR radiation
  • defence against long-term, delayed biological damage, thanks to the "PRO-REPAIR Complex" included.

This special complex is based on the synergistic action of niacin, the Beta-Glucan / L-Carnosine patented association and Vitamin E to stimulate the natural biological defences of skin, counter the effects of free radicals and photoimmunosuppression and support the natural cellular DNA protection and repair mechanisms.