Sunscreening – How, When and With What

Sunscreening – how, when and with what

Enjoying the psychological benefits of sunshine and keeping your skin in the style to which you’re accustomed need not be mutually exclusive. Modern sunscreens are formulated to offer protection against the full spectrum of damaging rays.

Getting blanket protection

The first commercial sunscreens, which came onto the US market in 1928, were based on chemicals that absorbed the energy of UVB rays. These were developed solely with the aim of preventing burning: neither the existence nor effect of UVA was yet known. Indeed, by the seventies — the days of baby oil and tin- foil reflectors, of mahogany jet- setters and quick-tan competitions — it seemed the only reason to wear sun creams was so that you could avoid a sunburn so painful it might keep you from roasting yourself further. The beautiful people sported skins the colour of antique furniture and anyone who dared expose a piece of flesh paler than a deli- cabinet roasted chicken was rewarded with snorts of derision.

A decade later, the effects of the searing seventies could be seen in the rising incidence of skin cancer, (up 90 per cent between 1974 and 1989). Greater attention was focused on cutting out the short UVB wave that caused it. Then, it was thought if you could inhibit burning but allow the passage of UVA you could induce a safe tan. ‘The short-term aim of the sunbather,’ wrote John V Simmons in The Science of Cosmetics (volume 1 of Science and the Beauty Business), ‘is a rapid tan with no sunburn. The sunscreen they require is one which ideally would let through UV-A but not UV-B.’ And so sunscreen manufacturers triumphantly launched products which they claimed were the solutions to the sunbather’s conundrum. One brand’s advertisement, for example, promised simply, ‘turns ultra-violet into ultra brown’.

But, of course, a sunscreen which lets through UVA also allows the acceleration of the ageing process, and possibly also the formation of skin cancers. By the mid 1980s, skincare companies which spent millions on researching and developing creams to keep skin looking young and beautiful were scrabbling around for UVA filters to put in their face-saving preparations. But filtering out UVA is no easy task — most UVB filters have little or no effect on A. Casting around for ways to combat UVA, scientists looked again at the physical sun blockers.

Zinc oxide and titanium dioxide pastes had long been known to obstruct the sun’s rays. The advantage of physical reflectors over chemical absorbers is two-fold. Firstly, physical blockers reflect the sun’s rays equally and secondly, they are inert and so, unlike some chemical filters, won’t induce irritant reactions. The cosmetic catch, however, was that these compounds are opaque. Cricketers who spend all day in the outfield are happy to sport white stripes, but the gilded goddesses sunning themselves on the Club 55 beach in St Tropez are not. For them, the solution came in the form of the micronized particle. If you take zinc oxide and titanium dioxide and mill it down to a fine powder which you then blend into a cream or lotion, it’s possible to get an almost invisible physical barrier.

Today, the most efficient sunscreens are those which offer broad spectrum protection – that is, that block or filter out UVA, UVB and infrared rays. New chemicals capable of absorbing UVA have been developed (eg Parsol 1789) but often sunscreen manufacturers can best achieve blanket protection by concocting a blend of chemical absorbers and physical blockers.

Beauty Spot:

Antioxidants are often used in sunscreens, the idea being that any free radicals generated by the odd UV rays that do get through will be quenched before they do any damage. Indeed, although not currently accepted as photo-protective agents in their own right, some experts are beginning to think of antioxidants as essential sunscreen ingredients.

Deciphering the labels

Know your SPFs

Contrary to popular opinion a preparation’s SPF (Sun Protection Factor) doesn’t tell you the amount of time you can spend in the sun without getting burnt but the amount of extra time. For instance, if your skin normally burns after 20 minutes, an SPF8 means you can expect to inhibit burning for 20 x 8, ie for 2 hours and 40 minutes. SPF20 would prevent burning for over 6 hours.

SPF – how high can you go?

SPF15 blocks out about 93 per cent of UVB and SPF20 about 97 per cent. You might think that there’s little to choose between the two. Certainly the Australian authorities thought as much and restricted the labelling of sunscreens to a maximum of SPF15. In the US, where there is no such restriction, SPF32, 60 and upwards are not unheard of. However, recent findings have shown that the extra 4 per cent protection offered by SPF20 may well be significant in the prevention of skin cancers and it is currently being proposed that the upper limit be raised.

Broad spectrum means that the cream screens out both UVA and UVB. It does not, however, give you any indication of the degree of protection offered.

Vitamins A, C and E means that the cream contains antioxidant vitamins designed to help neutralize free radicals.