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Information about the sun, sunscreens and your skin

Posted by Dr James Burt on 12 June 2016

What is UV anyway?

The sun radiates light and heat towards the earth. We classify the different components of the sun's energy according to visibility and wavelength. Ultraviolet (or UV) radiation is part of the invisible energy transmitted from the sun.

Ultraviolet energy is important to us because it is responsible for much of the problems we see with skin cancer and equally importantly it is responsible for up to 90% of the ageing effects we see in our skin as we get older.

Is all UV the same?

No. All UV is not the same. UV can be divided into UV-A and UV-B.

UV-B. We have all been hearing about UV-B for the last twenty years or so. UV-B largely penetrates just the upper most layers of our skin and is responsible for acute sun damage, including sunburn and some non melanoma skin cancers.

UV-B is accounts for only a small proportion of the radiation reaching us from the sun. It is strongest near the equator (i.e. northern Australia and the tropics) and during summer months.

UV-A. Very few of us are aware of UV-A and how it fits into our understanding of how our skin interacts with the environment. UV-A is the great untold story of skincare and sun protection.

UV-A is relatively constant throughout the year. It penetrates glass exposing us to potential damage at home, work and in the car. UV-A accounts for a far greater percentage of our total UV exposure compared to UV-B.  UV-A penetrates deep into our skin and is responsible for ageing, elastic tissue damage and skin cancer including melanoma. It causes all these changes without sunburn so your skin can be damaged throughout the year summer and winter without you even realising.

What is sun related (photo-) aging?

Aging effects which can be attributed to sun damage are: wrinkles, roughness, mottled pigmentation, and loss of skin tone and elasticity. (Up to 90% of these changes may be sun related).

Daily use of a true broad spectrum UV-A and UV-B sunscreen is essential to prevent acute and chronic sun damage and premature ageing.

What is SPF?

SPF (Sun Protection Factor) is only a measure of UV-B protection. SPF tells you that, in ideal circumstances, if it normally takes fifteen minutes for your skin to start to get pink when exposed to the sun (called the minimal erythema time) that with an SPF 15 sunscreen applied to your skin it should take 15 times fifteen minutes for you to notice redness. (This is providing you reapply every two hours; and assumes the sunscreen does not wash off from swimming or perspiration, or is not rubbed off playing sport or on your towel etc).

Because UV-A exposure does not lead to redness or sunburn SPF does not tell you anything about how much real sun damage and premature ageing is occurring.

If you think about this for a moment high SPF sunscreens may be leading us to increase damage to our skin. When we have good UVB protection (SPF 30+) we may stay out in the sun for long periods in comfort because there is no sunburn but all the while we are accumulating UV-damage.

What is the solution?

The solution is true broad spectrum UV-A and UV-B protection.

Most popular sunscreens currently used provide UV-B and partial UV-A protection. Knowing which ingredients protect against UV-A is the key.

The key ingredient is micro fine zinc oxide, or micro fine titanium oxide.These ingredients provide far greater UV-A protection.


The new formulations are translucent .The additional advantage is that because zinc oxide is not absorbed into your skin it is never irritating (most sunscreens have added preservatives which could still conceivably irritate extremely sensitive skins). Zinc oxide is recognised by the United States Food and Drug Administration as a Category 1 skin protection agent classifying it as safe for use on damaged skin. There are no known adverse reactions and zinc cream has been a long time staple for treating skin conditions in infants and babies. This profile makes it ideal for use in sunscreens and daily moisturisers.

Which zinc oxide sunscreen is best for me?

Currently available preparations contain micro fine zinc oxide in concentrations of 2 to 8 %. Higher concentrations give the greatest protection.

Choose a daily use product that contains micro fine zinc or titanium oxide and has SPF15+ or greater.

Daily use products should be non greasy and cosmetically elegant and can be worn under make up or without makeup as desired.

For the beach, swimming or sports use a waterproof product. These feel heavier and often feel greasy .these characteristics are necessary to make them durable during these activities.

Be sun smart!

No sunscreen is perfect protection.  Staying out of the sun from 10 am to 3pm, broad brim hats, protective clothing and sun glasses remain indispensable weapons in protecting your skin from premature ageing and skin cancer.

To get further information or to make an appointment to get the best treatment for your skin contact Dr James Burt's rooms in Melbourne now.

Dr James BurtAuthor: Dr James Burt
About: Dr Jamie Burt was born and educated in Melbourne, attending the University of Melbourne and graduating with MBBS in 1998. He is a member of the Senior Medical Staff at St. Vincent’s Hospital, Melbourne, and was Head of Reconstructive and Plastic Surgery at the Peter MacCallum Cancer Institute until 2004. Known for his respectful, informative, and caring approach, Jamie has been caring for patients for over 15 years.
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Tags: Skin Care

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