In Australia the labelling of sunscreen products differs depending on whether the product is a primary or secondary sunscreen product. A primary sunscreen product is one that represents itself on the label as being primarily to protect the skin from the sun's harmful rays. This differs from a secondary sunscreen product which may have some sunscreen properties but has another primary function such as being a moisturiser or a make-up. Secondary sunscreens can only claim a maximum SPF of 15+. Any product labelled SPF 30+ is a primary sunscreen.
There are different labelling requirements for primary and secondary sunscreens. Primary sunscreens are considered to be therapeutic goods and are regulated as medicines under the Therapeutic Goods Act 1989 and must comply with the Therapeutic Goods Labelling Order, The Therapeutic Goods Advertising Code and the Australia/New Zealand Standard AS/NZS 2604:1998 3.
Currently sunscreen products sold in Australia are required to show the sun protection factor on their label with a numerical value not greater than 30+ and clear/adequate directions for the use of the product. The name of all active ingredients must also be stated on the sunscreen including its broad spectrum and water resistance properties as well as the expiry date and storage conditions based on stability data to be shown on the container. The expiry date for sunscreens is usually one to two years but varies among manufacturers depending on the chemical constituents used.
The current Australian sunscreen standard (AS/NZS 2604:1998 'Sunscreen products - Evaluation and classification') limits the maximum protection claimed on labelling of sunscreen products to SPF 30+. This means that SPF 30+ is the highest rating that can be used for labelling sunscreen products in Australia. However this standard is currently under review and it is likely that the new standard will be in line with a new international or ISO standard and will allow higher SPF claims to be made.
Most people do not apply enough sunscreen to achieve the SPF rating on the label. There are concerns therefore that if labelling sunscreen with a higher SPF, the consumer may be likely to use less sunscreen and reapply less regularly so that the sunscreen protection becomes less effective even though it has a higher SPF number. It is important to remember that no matter how high the SPF some of the sun-burning radiation does get through.
Zinc oxide and titanium dioxide are visible when used in sunscreens, which gives the skin a white colour when applied. Nanotechnology breaks down these ingredients to minute particles so that when used in sunscreens they virtually disappear but still help effectively shield us from harmful rays. Nanoparticles of titanium dioxide and zinc oxide are routinely used in many sunscreens now for sale in Australia.
Concerns of nanoparticles in sunscreen relate to the theoretical possibility that if nanoparticles enter the human body through the lungs, skin or intestinal tract it is a concern to human health. Nanoparticles could possibly be absorbed into skin cells in people with eczema or acne or other conditions where the skin is damaged and the skins natural barrier function is not in tact. It is also possible that the particles can interact with sunlight to further increase the risk of damage to these cells.
There are many products that use nanotechnology which are already in our homes. A few examples include: clothing and material made of wrinkle, stain and odour resistant fabric, cosmetics and toiletries with nano-oxides of iron, aluminium, zirconium, silicon and manganese, and sunscreens with nanoparticles of titanium dioxide and/or zinc oxide for more transparent UV protection, teeth cleaners, toothpaste, condoms, wound dressings, dummies and other baby products with nanosilver. But whether the particles in sunscreens pose direct health risks to humans depends mainly on whether they penetrate the protective outer layers of dead skin. Studies suggest they do not reach live tissue under normal circumstances and has not shown any long term adverse effects from using sunscreens in humans. However, there is little research into the impact of these substances when the protective outer skin layers are damaged.
The TGA conducted a review which 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.
The Australian Medicines Evaluation Committee endorsed this conclusion.
The TGA is continuing to monitor the emerging scientific literature to ensure appropriate action is taken should any tangible safety concerns be identified and to date, mandatory labelling of nanoparticles in sunscreens has not been introduced anywhere in the world. The TGA does not require any specific warnings about nanoparticles to be placed on labels of sunscreens.
In Australia, all active ingredients, such as zinc oxide and titanium dioxide, must be declared on sunscreen labels, to help consumers make informed choices. However, it is not currently a requirement for sunscreen labels to declare the particle size of the active ingredients.
In general it is advisable to take a cautious approach particular in using preparations containing nanoparticles on skin where the protective surface is damaged.