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Sunscreen FAQ’s or Fiction
We’d like to set the record straight and answer some very commonly asked questions, as well as dispel some commonly held myths.
What is UVA radiation?
UVA radiation penetrates deep into the skin, affecting the living skin cells that lie under your skin's surface. UVA causes long-term damage like wrinkles, blotchiness, sagging and discoloration, and also contributes to skin cancer.
What is UVB radiation?
UVB radiation penetrates the top layer of skin and is the main cause of sunburn.
What is Sun Protection Factor (SPF)?
SPF – or Sun Protection Factor – is a measure of a sunscreen’s ability to protect the skin from UV radiation. SPF is calculated by comparing the amount of time it takes to produce the first sign of redness on unprotected skin versus the time taken to produce redness on skin that has been protected.
For example:
If your unprotected skin reddens in 10 minutes then an SPF 30 sunscreen will give you 300 minutes of protection. (This an example only and the time it takes your skin to show the first signs of reddening will vary.)
Currently, the Australian regulatory authorities allow a maximum rating on the label of SPF30+ for sunscreens sold in Australia even if the actual SPF maybe higher.
What about Vitamin D?
Vitamin D can be found in small amounts in foods such as dairy products, cereals with added vitamin D added, and fish. However, skin exposure to the sun provides as much as 80-90% of the body’s vitamin D.1 Vitamin D helps to maintain healthy skin and bones by promoting calcium absorption in the body. Because of the risks of overexposure to UV radiation, consistently and deliberately spending time out in the sun without any form of sun protection when the UV index is 3 and above is not recommended. 2
As an alternative to obtaining Vitamin D through exposure to sunlight, Vitamin D can be obtained from the diet. As standard and fortified foods may not contain enough Vitamin D to ensure adequate levels through normal dietary intake, oral supplementation is recommended for some groups including the elderly, and those who avoid the sun, or spend long periods of time indoors. 2 Talk to your healthcare professional about vitamin D supplementation.
1. Cancer Council WA. Skin Cancer flyer. How to be Sun Smart Flyer.
2. The Cancer Council Australia. Position statement: UV Radiation & Vitamin D [online] [Cited on 8 May 2006] Available from URL: http://www.sunsmart.com.au/article.asp?ContentID=vitamin_d1
What’s Titanium Dioxide all about?
Titanium dioxide offers protection over a broad range of UVA and UVB, and it doesn’t break down like some other sunscreen ingredients. We know that UVB rays cause sunburn and skin cancer and that UVA rays cause aging and skin cancer. As both cause damage to the skin, it's important that your sunscreen has broad spectrum protection that shields out both types of rays.
Many active ingredients in sunscreens can break down in the sun if they are not formulated correctly and only provide protection against UVB.. Titanium dioxide is a physical blocker, which works by reflecting rays away from the skin. Other sunscreen ingredients, classified as chemical absorbers, work by absorbing UV rays and preventing them from penetrating the skin. Sunscreens containing physical blockers have less allergy potential, but can leave a sheen when applied that some may not find aesthetically pleasing. Working in synergy, a combination of both chemical absorbers and physical blockers provide broad spectrum protection with a more elegant feel.
WebMd [online] 2008 [cited 12 August 2008] Available from URL: http://www.webmd.com/skin-beauty/news/20080708/8-burning-questions-about-sunscreens
Is a cream is better than a spray?
While a spray form of sunscreen is often viewed as more convenient, some experts say creams offer better coverage and are more likely to be used properly.1 It’s also not the optimal way to put on sunscreens because inadequate quantities tend to be applied and spread over the surface of the skin.
The nature of a cream requires it to be rubbed onto the skin, and as a result is a better form for sunscreens; although you can also rub sprays onto the skin. Long term skin damage can occur if you apply too little sunscreen, fail to cover all exposed areas of your body, or allow your sunscreen to be washed off by water or rubbing.
For your sunscreen to work, it needs to be properly applied. To achieve the specified SPF, apply roughly 2mg of sunscreen per square centimetre of exposed skin. For an average person, that’s 35mL for your entire body – or around 1 teaspoon per limb.
Sunscreen should be applied at least 20 minutes before you go outside and then re-applied after swimming, rubbing or towelling off. You should reapply every 2 hours.
1. WebMd [online] 2008 [cited 12 August 2008] Available from URL: http://www.webmd.com/skin-beauty/news/20080708/8-burning-questions-about-sunscreens
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