What does SPF mean?
Many people are confused about SPF labeling. SPF means ‘Sun Protection Factor’ and relates only to a sunscreen’s ability to protect from sunburn. It does not imply protection from ageing, freckling or tanning, but does imply protection from skin cancer.
An SPF factor 15 sunscreen will allow you to spend fifteen times as long in the sun without getting sun-burnt. So, if at midday it takes only half an hour to become sun-burnt, wearing an SPF factor 15 sunscreen will allow you to stay in the sun for seven and a half hours without getting burnt. An SPF 40 sunscreen would allow you to stay in the sun for twenty hours without getting burnt, but of course a factor 40 sunscreen would be pointless because the sun doesn’t shine for a straight twenty hours. It must also be remembered that sunscreens are tested in indoor conditions, and how this translates to outdoor conditions is really unknown.
Chemicals in sunscreens
Traditional sunscreens contain PABA (Amino Benzoic Acid). Because this caused a significant number of allergic reactions other chemicals have now largely replaced it. These include benzophenone, butyl methoxydibenzoylmethane, cinnamates and titanium dioxide.
There are several new and exciting developments in the sunscreen field. One company is investigating the possible use of ‘natural’ sunscreens derived from coral. Coral is able to protect itself from sunlight by secreting a substance which coats its outer surface. If this can be successfully extracted and is found to be safe in humans, it may prove a good alternative to the currently available preparations.
Many solariums advertise the promise of a safe tan, and promote the notion that if one regularly uses a solarium one is less likely to develop sunburn. But there is no such thing as a safe tan. Any tanning of the skin is an indicator of sun damage and of increased skin cancer risk.
Because solariums contain a higher percentage of ultraviolet A light, they lead to premature ageing of the skin and abnormal pigmentation – a high price to pay for a so-called ‘healthy’ tan. At the present time there is nothing to recommend solarium use, except for people with psoriasis.
These creams contain a chemical called dihydroxyacetone which colours the skin brown. They appear to be safe and non-damaging to the skin, and are certainly preferable to sunbathing or using a solarium. They do protect the skin from ultraviolet light to some extent but should not be used as a substitute for a sunscreen. Clarins, Ella Bache and Lancome all make good products.
Some fake tans were withdrawn from the market because they contained urocanic acid which was shown to promote skin cancer in animals. Since urocanic acid is not an essential ingredient, it is no longer used in these creams.