What you must know about sunscreen

by Colin Cable, RPS Assistant Chief Scientist

Summer is coming. But when the sun comes out do we all know how to protect ourselves from its damaging rays?

To try and get a feel for the public’s understanding of sun protection the Royal Pharmaceutical Society carried out a survey – and about the types of damaging ultraviolet (UV) radiation, sunscreen labelling and how to use sunscreens effectively.

Only 8% of those surveyed knew that the SPF rating on the product label refers to protection from UVB rays only – and does not also include protection from harmful UVA rays – typically indicated by a separate ‘star’ rating.  More than 80% said they either thought the SPF was an indication of levels of protection from both UVB and UVA or they simply did not know what the rating stood for



Two types of UV radiation reach the earth from the sun. Ultraviolet A (UVA) radiation is mainly linked to skin ageing while ultraviolet B (UVB) radiation is strongly linked to sunburn, although both UVB and UVA are linked to skin cancer. To protect the skin from the sun the ideal would be to wear clothing that covers the skin including hats and sunglasses. However, this is often not practical and sunscreens offer a means of reducing the risk of skin damage by the sun.

To give a good level of protection, sunscreens should protect against both UVA and UVB. The level of protection offered against UVB is shown by the sun protection factor (SPF) with a higher number giving greater protection. For UVA, the label may give a star rating (from one to five stars) or a logo with ‘UVA’ within a circle which is used in Europe to show the sunscreen meets the recommended minimum required level of protection to UVA.

How much to use?

However, the level of protection the sunscreen offers relies on applying enough of it. About 35 ml of sunscreen (a golf ball sized amount) is needed to cover the average adult body, though it is estimated that most people only apply about a quarter of this amount. Sunscreens should also be applied every two hours and re-applied after exposure to water, sweating, towel drying and abrasion by sand which can cause their removal.

What level of protection is best?

The National Institute for Health and Care Excellence (NICE) recommends a minimum SPF of 15 to give UVB protection, alongside a UVA with at least 4 stars to give UVA protection, assuming that the correct quantities of sunscreen are applied. The British Association of Dermatologists recommends a sunscreen of SPF 30 and a UVA rating of 4 or 5 stars as providing a good standard of sun protection.

One group of patients that are particularly prone to the effects of UV radiation are those who are taking medicines likely to cause photosensitivity, with doxycycline being one of the more common examples. On exposure to UV radiation the patient’s skin can take on an appearance similar to sunburn. Patients taking these medicines should be advised to avoid sunlight wherever possible; if avoiding sunlight is not possible, clothing that gives protection to sunlight should be worn and a sunscreen with a high SPF applied.

It is virtually impossible to completely avoid exposure to ultraviolet radiation and most people enjoy being out and about in the sun. Ask your local pharmacist about sunscreen and take precautions to minimise damage to the biggest organ of your body – your skin.

The RPS has a new quick reference guide for pharmacists on sunscreen.

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