Sunscreen – Questions and Answers
What is sunscreen?
Sunscreen is a cream, lotion or spray that is applied to the skin to provide protection from the ultra violet radiation (UV) within the sun’s rays that causes sunburn or more serious damage over time.
What is sunblock?
Some manufacturers used to label their best products as ‘sunblocks’ rather than ‘sunscreens’ because they blocked more of the harmful rays from the sun. This term is rarely used now though because it was inaccurate and misleading as none of the products ‘blocked’ the sun completely.
What does SPF mean?
SPF or Sun Protection Factor is a measure of the effectiveness of a sunscreen. If, for example, you normally burn in 10 minutes without sunscreen it will take 15 times longer (ie 150 minutes) if you use a sunscreen rated as SPF 15. However, this is only true if you have applied enough sunscreen to give you the ‘standard’ amount of SPF 15 protection. In the UK and the rest of the EU the SPF scale ranges from 6 to a maximum of 50+.
How much sunscreen do I need to use?
The specified SPF rating depends on the application of a standard amount or thickness of sunscreen and it’s calculated by applying 2 milligrams per square centimetre of skin. This doesn’t really mean much to most people, but it equates to about 1 or 2oz (28 – 56g) of product to cover the whole body – which is roughly a palm-full of sunscreen. Studies show that most people only apply half or even a quarter as much as they should do – so the level of protection they think they have is much less than the protection they actually have. Consequently, one way around this could be to use a sunscreen with a higher SPF – so if you think you only need to use SPF 15 – use SPF 30 instead, just to be on the safe side.
How often should I reapply sunscreen?
Generally, sunscreen should be reapplied every 2 hours – and more often if it is washed off by sweat or swimming, etc. It should also be remembered that you can’t get around this by applying a sunscreen with a higher SPF – if you use SPF 30 instead of SPF 15 it will still only remain effective on your skin for 2 hours – not 4 hours.
So what about the ‘once a day’ products?
The ‘once a day’ products that last for 8 hours or more are fine if they’re used exactly as specified. The 8 hour protection depends on the application of a sufficiently thick layer of sunscreen over the area that needs protection. It must then remain intact for the entire period, and it should not be degraded by exposure to water, sweating or abrasion from clothing or anything else rubbing against the skin. In practice, it’s actually quite difficult to make sure you’ve applied enough all over and haven’t missed a bit, so it’s much easier just to reapply it at regular intervals and top up any areas that need a bit more.
So is SPF all I need to think about?
No! There are two types of UV radiation that are a cause for concern – UVA and UVB – and the SPF rating is only a guide as to how effective a sunscreen is at blocking UVB radiation – the type that causes sunburn. UVA radiation causes wrinkles and premature ageing of the skin – and both UVA and UVB radiation can lead to an increase in different types of skin cancer – so ideally you should use a broad spectrum sunscreen that is able to protect you from both.
What is a broad spectrum sunscreen?
A broad spectrum sunscreen contains active ingredients that provide protection from both UVA and UVB radiation from the sun.
How do I know how good a broad spectrum sunscreen is?
The UVB protection is indicated by the SPF rating which goes up to a maximum of SPF 50+. The UVA protection is indicated by the UVA circle symbol in the EU and by the 5 star rating in the UK – 1 star being the lowest level of protection and 5 star being the highest. It’s slightly more complicated than that though because the UVA protection is also related to the SPF of the product: it’s calculated as a percentage of how good the product is at blocking UVB radiation – so a 5 star SPF 30 product won’t block as much UVA radiation as a 5 star SPF 50 product. It’s slightly more straightforward with the UVA circle symbol because it indicates that the product blocks at least a third of the UVA radiation, relative to the amount of UVB radiation blocked by the product, which is determined by the SPF.
What are the active ingredients in sunscreen?
The active ingredients fall into two main categories – organic and inorganic. Organic in this case has nothing to do with organic farming – it refers to a group of ingredients that act as ‘chemical’ filters by absorbing UV radiation and re-emitting it as infrared warmth. Inorganic ingredients are minerals that act as ‘physical’ filters by reflecting and scattering UV radiation away from the skin without changing it into anything else.
Typical organic ingredients:
Typical organic ingredients include avobenzone, cinoxate, ecamsule, menthyl anthranilate, octyl methoxycinnamate, octyl salicylate, oxybenzone and sulisobenzone. Organic ingredients are much more effective at absorbing UVB radiation than UVA radiation.
Typical inorganic ingredients:
Typical inorganic ingredients include titanium dioxide and zinc oxide. They reflect and scatter both UVA and UVB radiation so they are often included with organic ingredients in a sunscreen to improve the UVA protection.
Are there any ‘bad’ ingredients that should be avoided?
The main ingredient of concern is P-Aminobenzoic acid, which is better known as PABA. However, this has now been banned in the EU because of concerns about its link to an increase in DNA defects. All the other ingredients in use have of course been approved by the authorities, although the legislation does vary from country to country. It doesn’t necessarily follow though that all the ingredients are ‘safe’ for everyone to use, because there will always be somebody somewhere who reacts adversely to something, and knowledge and awareness of potential concerns is increasing all the time. Consequently, if in doubt, check it out with a medical professional – we’re not qualified to offer advice!
Can I buy waterproof sunscreen?
The term ‘waterproof’ is rarely used now and it’s actually prohibited in many countries because no product is truly waterproof. It has been replaced by the term ‘water resistant’ and a time period should also be stated – either 40 or 80 minutes – and an instruction to reapply the product after towel drying and at least every 2 hours.
Do I still need to wear sunscreen when it’s cloudy?
You should certainly consider it, because just like daylight some of the UV radiation is able to pass through the clouds – it doesn’t go completely dark when it’s cloudy!
Do I still need to use sunscreen if I’m up in the mountains and it’s freezing cold?
Yes! It’s not the heat from the sun that’s the problem – it’s the UV radiation – and this is more intense when you’re up in the mountains (you’re closer to the sun!). UV radiation is also reflected by snowy surfaces so you get a double dose – from both above and below.
Why do I burn more easily on the beach or on a boat?
Firstly, it can be quite difficult to find any shade on a beach or a boat. Secondly, a lot of the UV radiation is reflected by the sea and the sand so you get a double dose – from both above and below.
What about children?
Young children have more delicate skin than adults so protection from the sun is even more important. Ideally they will keep out of the sun or cover up, but failing that a good quality sunscreen should be used. There are many products formulated and labelled as suitable for children and generally these can be used without any problems. However, most products state they shouldn’t be used on children less than 6 months old to further reduce the likelihood of an adverse reaction – and if in doubt medical advice should be obtained.