Sunscreen is one of the most common methods of sun protection. SunSmart recommends SPF 30 or higher broad spectrum, water resistant sunscreen.
In laboratory conditions, when used as directed, SPF30 sunscreen filters 96.7% of UV radiation and SPF 50 filters 98%. Both provide excellent protection as long as they are applied properly. ‘Broad-spectrum’ means that the sunscreen filters both UVA and UVB radiation.
When using sunscreen, remember:
- No sunscreen provides full protection so never rely on sunscreen alone for sun protection. During the daily sun protection times (when the UV Index is 3 and above), combine sunscreen with sun-protective clothing, a broad-brimmed hat that protects the face, head, neck and ears, shade and sunglasses.
- Apply sunscreen 20 minutes before you go outside and again every two hours (whether or not the label tells you to do this).
- Use a generous amount of sunscreen. The average-sized adult should apply more than half a teaspoon of sunscreen (about 3 ml) to each arm and the face/neck (inc uding ears), and just over one teaspoon (6 ml) to each leg, the front of the body and the back of the body. That is, approximately 35 ml of sunscreen for one full body application.
- Check and follow the ‘use by' date stated on the packaging and store sunscreen below 30°C.
- If you have an allergic reaction to a sunscreen, try another brand or look for a fragrance-free product such as a toddler or sensitive sunscreen. A doctor or chemist could also offer advice about choosing another product.
Sunscreen and babies
The Australasian College of Dermatologists states that because very young babies (less than six months of age) absorb more of any chemical applied to the skin than adults, the widespread regular use of chemical sunscreens is not recommended. The American Academy of Pediatrics has stated that sunscreens may be used on infants younger than six months on small areas of skin if adequate clothing and shade are not available. However it is best to keep babies under 12 months out of direct sun during the sun protection times, or well protected using other forms of sun protection. Many brands of sunscreen have a baby or toddler formula. These are just as protective, but gentler on their skin. Test the sunscreen on a small area of the child’s skin before using it, to make sure there is no reaction.
Sunscreen and children
Advice from the National Health and Medical Research Council states that children who are able to apply their own sunscreen (under supervision) should be encouraged to do so. This fosters independence and responsibility. For those unable to apply sunscreen, it is recommended that if a carer is doing 'mass sunscreen applying' they should wash their hands before and after the task. They can use a different tissue for each child when applying the sunscreen, however, unless the child (or the carer) has a visible skin disease or a cold/virus, it is not really an infection-control issue. If a child does have a visible skin disease e.g. eczema or open skin wound, or a cold/virus, their sunscreen should be applied last using gloves or a tissue.
Sunscreen and nanoparticles
Nanotechnology has been used in sunscreens for many years. To date, the Cancer Council's assessment, drawing on the best available evidence, is that nanoparticulates used in sunscreens do not pose a risk. However, we continue to monitor research and welcome any new research that sheds more light on this topic.
Sunscreen formulas and their components are regulated through the Therapeutic Goods Administration (TGA). In early 2009, the TGA conducted an updated review of the scientific literature in relation to the use of nanoparticulate zinc oxide and titanium dioxide in sunscreens.
The TGA review concluded that the potential for titanium dioxide and zinc oxide nanoparticles in sunscreens to cause adverse effects depends primarily upon the ability of the nanoparticles to reach viable skin cells; and to date, the current weight of evidence suggests that titanium dioxide and zinc oxide nanoparticles do not reach viable skin cells; rather, they remain on the surface of the skin and in the outer layer of the skin that is composed of non-viable cells.
Since the TGA’s review, more recent research into nanoparticles has been undertaken in Australia. A study published in early 2014 exposed human immune cells (called macrophages) to zinc oxide nanoparticles to see how they would respond. The study showed that the human immune system effectively absorbed the nanoparticles and broke them down.
The study did not look at whether the particles are absorbed through the skin and into the bloodstream. The current available evidence indicates that this does not happen and the particles remain on the surface of the skin.
Sunscreens also use ‘microfine’ or ‘micronised’ particles, which are larger than nanoparticles:
- Nanoparticles are smaller than 100 nanometres and invisible to the human eye – a nanometre is 0.000001 millimetre.
- Microfine particles are smaller than those used in conventional white zinc sunscreens, however are larger than nanoparticles – usually in the range of 100 to 2500 nanometres.
In the manufacturing process used to produce microfine particles, some particles can inadvertently be ground smaller, ending up being classified as nano-sized. Manufacturers advise this is a small percentage of the total, generally less than one per cent and does not classify the sunscreen as nano-based.
Cancer Council looks closely at TGA's advice, as well as our own evidence-based reviews. There is no credible evidence that sunscreens containing nanoparticles pose a health risk. Sunscreen has been scientifically proven to reduce the risk of melanoma and other skin cancers.