With growing concern about the ozone layer and the damaging effects of the sun’s radiation, consumers are more than ever heading to the shops to purchase sunscreen products. But the barrage of sun care products on the market can often leave the consumer in bewilderment. From the marketing hype of beautiful European models on bottles, to so-called tropical formulas, or just common household name brands that have attained this level through massive advertising campaigns, the choices are overwhelming. To help sift through this vast array of options, we can begin by categorizing sunscreens into two major types depending on the type of active ingredient used:
- chemical sunscreen formulas
- physical sunscreen formulas
The chemical sunscreen formulas use different chemicals as the active ingredients; these chemicals basically absorb the ultraviolet (UV) radiation from the sun. Chemical sunscreens represent at least 95% of the products on the market. The physical sunscreen formulas use very fine mineral powders, which actually reflect the UV radiation. Herein lies one of the major benefits of the physical sunscreens over the chemical based ones: the chemicals can be absorbed into the skin, whereas the physical blocks are not absorbed into the skin. Furthermore, physical blocks tend to be more photo stable (that is, they do not breakdown with constant exposure to the UV radiation).
Scientists and doctors around the world have been observing increased rates of skin cancers despite the increased awareness of the hazards of too much sun, and the increased use of sunscreens. Even accounting for the fact that there may be an increased level of detection, the overall increased rates do not make sense. The first of two predominant hypotheses for this phenomenon is the possibility that the use of chemical based ingredients, which absorb UV radiation, are being absorbed into the skin over an extended period of time and affecting the level of health. The skin is an organ of the body that has the ability to absorb things. Most people are familiar with the concept of the nicotine patch (”the patch”) to quit smoking; many types of medications are being developed to use this type of transdermal absorption mechanism. Now consider the large surface area of the body and the potential for absorption when it is completely covered with sunscreen at the beach! A recent finding at the Department of Biochemistry, Oxford University in England is as follows:
We have tested the mutagenicity of a UV-B sunscreen ingredient called Padimate-O or octyl dimethyl PABA, which, chemically speaking, is identical to an industrial chemical that generates free radicals when illuminated. It is harmless in the dark but mutagenic in sunlight, attacking DNA directly. A commercial sunscreen containing Padimate-O behaves in the same way. UV-A in sunlight also excites Padimate-O, although less than UV-B. As mutagens may be carcinogenic, our results suggest that some sunscreens could, while preventing sunburn, contribute to sunlight-related cancers.
( Sunlight-induced mutagenicity of a common sunscreen ingredient. J Invest Dermatol 1997 Jun;108(6):859-863
Knowland J, McKenzie EA, McHugh PJ, Cridland NA Department of Biochemistry, South Parks Road, Oxford OX1 3QU, UK. )
The other hypothesis is that many sunscreens may be giving a false sense of security. When you are exposed to sunlight, there are two types of UV radiation that hit your skin: UVB rays and UVA rays. The UVB rays are basically the shorter rays and these are what burn the skin; in fact, this is nature’s way of telling you that you have had enough. UVA rays are longer, more penetrating rays that are associated with skin damage and even cancers. The UVA rays do not cause burning of the skin and, therefore, have not been adequately addressed in sunscreen formulas.
Until recently, most formulas just blocked the UVB rays. The products have been rated with an SPF value, which tells you how many times longer you can stay in the sun before burning, than if you were unprotected. For example, if at mid-day a fair skinned person begins to burn after 20 minutes, then a sunscreen formula with an SPF value of 8 will protect him from burning 8 times longer, or 160 minutes. But now nature’s built-in alarm mechanism of making you burn when you have had too much sun has been by-passed, and this person is still being exposed to and absorbing the UVA rays.
Because of this newer understanding of UVA rays, newer chemicals are being added to help protect against the UVA rays. Unfortunately, though, they only block a small portion of the UVA spectrum, and there are concerns of the photo stability of these ingredients. This is one of the major advantages of using the more natural physical sunscreens. They block a wider spectrum of the UVA rays and, therefore, give better, more complete long term protection. The two main physical sunblock ingredients used are zinc oxide and titanium dioxide. Zinc oxide tends give the greatest protection and has a long history of use in cosmetics. It is the only FDA approved ingredient that is categorized as a sunscreen formula protecting from both UVB and UVA rays, and which is also categorized as a skin protectant. Zinc oxide can be commonly found in baby diaper rash formulas, skin ointments, and the familiar old thick white sunblocks used by lifeguards to cover their noses.
There are now new, transparent forms of this zinc oxide-based sunscreens which use a special zinc oxide called microfine or micronized zinc oxide. This type of sunscreen does not leave a thick white covering, but rubs in transparent and still provides the widest UVB and UVA spectrum protection available. Although this has superb performance and rubs in really easily it does use 'nano-technology' and there is a growing body of experts who believe that this 'nano-technology' is harmful to the body. (Caribbean Blue no longer uses microfine zinc oxide). When deciding on which SPF factor to use, it is important to point out that a factor15 is the maximum needed. This will block about 94% of the UVB rays. Using a factor 30 may give only marginally more protection blocking about 96%. It is for that reason that many doctors recommend the maximum 15. Above that is more marketing hype a way for manufacturers to charge more.
Armed with this new information, it makes common sense which type of product would be better to use. So why are there not more of these types of products available. First, most of these companies are extremely large and to change a product requires lots of time and expense. Second, much of this information is relatively new. Finally, the cost of manufacturing a physical sunscreen versus a chemical one can be two to three times, resulting in a more expensive product for the retailers. Hence the reason why only the upscale companies have started to include physical sunblocks in their range of products. Just remember, you usually get what you pay for!
If you are looking for a sunscreen that is truly natural, you need to ensure that it has a natural base, free of synthetic fragrances, colour, emulsifiers, and preservatives. Only then you can be sure that it is the healthiest and the most gentle, even on sensitive skins and on babies. The Caribbean Blue-natural basics suncare line has one such brand called Sun Shield. It is produced in St. Lucia, developed by doctors, and available at leading stores. Not only does it use zinc oxide physical sunscreen, but the entire product is natural: natural plant essential oils, instead of synthetic fragrances, no chemical emulsifiers, no artificial preservatives, only herbal extracts, antioxidant vitamins and natural plant oils.