Sunscreens Explaining The Jargon

Choosing a sunscreen can be very confusing as there are many different ingredients and jargon such as SPF, UVA, UVB and broad spectrum. At Soltrino, we’ve been as confused as anyone else when trying to choose the best sunscreen for our families. In this article, we explain what a sunscreen is, whilst promising not to get too technical…

Sunscreens are products containing ingredients called UV filters. These are chemical substances which act as sunscreens, stopping the sun’s UV rays from reaching and damaging the skin.

They typically fall into two categories:  inorganic or mineral filters, such as zinc oxide and titanium dioxide, which act as mirrors reflecting and/or absorbing the UV radiation; and synthetic or organic filters, which act as sponges absorbing and mopping up the UV radiation. Both types of filters can be combined to give optimum protection against UV radiation.

One important point to note is that when we use the term ‘organic’ we mean the chemistry definition i.e. when a substance contains a carbon atom, as opposed to the definition used to describe food and farming when the growing process does not use pesticides and manufactured chemicals. We don’t want you eating your sunscreen!

So Many Terms I Just Give Up! The jargon explained!

There are lots of terms and jargon but understanding them helps you choose the right sunscreen to protect you and your family, so it is worth trying to get your head around it.

SPF Stands For Sun Protection Factor

In essence, this means how much the sunscreen filters out UVB rays. UVB causes the sunburn or darkening of the skin so you can think of SPF as the sunburn protection factor. For example, SPF 30 means that 1/30th of UVB radiation will reach your skin, assuming that enough sunscreen is applied correctly.

Another way to think about it is to consider a person who can go out in the sun for 10 minutes without getting burned. If they apply an SPF 15 they should be able to stay outside without burning for 150 minutes (10 x15 = 150).

That means two people of differing skin types cannot use the same SPF sunscreen and stay outside in the sun for the same period of time safely.

As well as UVB, sunscreens need UVA protection, which we discuss below.

UVA Rating /Protection

Your sunscreen needs to have good UVA protection but the regulations and rules around UVA labelling differ around the world, so it’s worth understanding the jargon.

UK sunscreens will give a UVA star rating, a system developed by Boots (a large pharmacy chain). This rating indicates the percentage of UVA radiation that is absorbed by the sunscreen in comparison to UVB. 5 star means a SPF 30 which absorbs 97% of UVB also offers UVA protection absorbing 97%.


UK star rating


European manufacturers voluntarily comply with an EC recommendation that all sunscreens must offer UVA protection of at least 1/3 of the SPF value.

In other words, if a product advertises SPF 30, its UVA protection must be at least ten. This is shown by UVA inside a circle. So in the UK suncreens that meet this requirement will be shown as having a 3 star rating.


europe uva rating


Australia & New Zealand region, if a product is labelled as a broad spectrum sunscreen it must have UVA protection of at least a third of the SPF. It is optional for products with SPF between 8 and 30 to meet the requirements for broad spectrum. Sunscreens with SPF 30 to 50 must have a UVA of at least 1/3 of the labeled SPF to be labelled “Broad Spectrum”. Any claim of extra broad spectrum can only be made for products with an SPF of 50+.


In the US, FDA regulations mean that a sunscreen can not be labelled as broad spectrum unless it provides a certain level of UVA protection, measured by the sunscreen absorbing radiation up-to a certain (370 nanometres).

There are experts that believe this measurement doesn’t give enough UVA protection and that the UVB and UVA ratio provides better UVA coverage. There are US products that do not provide this level of UVA protection but they must carry a warning stating “Skin Cancer/Skin Aging Alert”.


Waterproof/Water Resistant?

Waterproof: No sunscreen is 100% waterproof so manufacturers can only use a term like water resistant to describe their sunscreen.

Water resistant sunscreens do not come off after swimming or exercise, as long as you don’t wipe them off by towel drying. Even if the label states a four hour water resistance, you still need to reapply every two hours to maintain the same level of protection and reapply immediately after swimming or towel drying.


Finally …What is photostability?

You should also check that your chosen sun protection is photostable. ‘Photostability’ means that UV filters do not break down in the sun.


If you have any concerns over your sunscreens or questions regarding the ingredients you should always talk to your doctor. For children under six months it is advised to keep them out of the sun and not apply sunscreen, unless advised to do so by your pediatrician.


Please read about the subjects further and if you do find any errors in our articles please let us know.


European Commission 2006, Colipa 2009