Sunscreen

Sunscreen has been proven to reduce the risks of melanoma, squamous cell carcinoma, and solar keratoses. It has also been shown to reduce visible signs of skin ageing (Green 2011, van der Pols 2006, Thompson 1993, Hughes 2013).

Regular use of sunscreen is also an important part of reducing the risk of skin cancer and managing long-term sun damage.

Use sun protection when the UV index is 3 or above. Sunscreen is one part of protection, alongside clothing, a hat, shade and sunglasses.

How does sunscreen work?

Sun damage and skin cancer are caused by ultraviolet radiation in sunlight damaging DNA in the genes of skin cells. Sunscreens help prevent UV from reaching these genes, either by absorbing or reflecting UV radiation.

See our guide to reducing skin cancer risk for practical UV and sun-protection advice.

Choosing a sunscreen

Choose a broad-spectrum, water-resistant SPF 50 or 50+ sunscreen that you can apply generously and tolerate comfortably. Check the label and expiry date. Mineral and chemical filters can both provide protection; the formulation matters more than a simple label.

For sensitive skin, try a fragrance-free formulation on a small area first. Price alone does not indicate protection. For babies, prioritise shade and protective clothing and ask a health professional about sunscreen use.

Apply sunscreen about 20 minutes before going outside. Water resistance does not remove the need to reapply after swimming, sweating or towel drying, and at least every two hours outdoors. No formulation should be treated as an all-day application.

Sunscreen failure

Some people apply sunscreen but still develop sunburn. Sunscreens sold in Australia are tested to ensure they work as advertised.

Sun protection is also important when managing pigmentation and protecting your skin before and after laser or BBL treatment.

The most common cause of sunscreen “failure” is inadequate application (Chipps 2016).

Applying and reapplying

For an average adult’s full body, use about 35 mL (seven teaspoons): one for each arm, one for each leg, one for the front of the torso, one for the back, and one for the face, neck and ears. Apply generously to all exposed skin.

Reapply at least every two hours outdoors and after swimming, sweating or towel drying. Creams and lotions make it easier to apply enough than aerosol sprays.

See Cancer Council’s sunscreen advice.

Avoid missed areas

It is easy to miss parts of your skin, especially your back. Ask someone to help with hard-to-reach areas where practical. Clothing, such as a T-shirt or rash vest, can help protect areas that are difficult to cover evenly with sunscreen. Reapply as directed even if the first application seemed thorough.

Storage of sunscreens

Sunscreens should be stored below 30°C and not used past their expiry date. Avoid storing sunscreen in a car.

Sunscreen and vitamin D deficiency

Vitamin D deficiency is common in Australia. Because sunlight helps the body produce vitamin D, some people worry that sunscreen might reduce vitamin D levels.

Studies have not shown a clear link between sunscreen use and vitamin D deficiency (Hanrahan 2012).

Safety

No product can be proven to be completely risk-free. However, strong evidence shows that the health benefits of sunscreen far outweigh potential risks.

Skin irritation

Some sunscreen ingredients may irritate sensitive skin. Finding a sunscreen that suits your skin may require some trial and error.

• Fragrances commonly cause irritation – unscented products are usually better tolerated.
• Physical sunscreens tend to irritate skin less often than chemical sunscreens.

Nanoparticles

Nanoparticles are very small particles of zinc or titanium used in some physical sunscreens. They reduce the white appearance common with older mineral sunscreens and can make products easier to apply.

Current evidence shows that these nanoparticles do not penetrate the skin or enter the bloodstream (Hanrahan 2012, Therapeutic Goods Administration 2020).

“There is no current evidence that nanoparticles are absorbed into the bloodstream or cause any health problems.”

Hormone disruption and cancer

Some people have raised concerns that certain chemical sunscreen ingredients could disrupt hormones or increase cancer risk. These effects have only been observed in animal studies using extremely high doses.

These doses would be very difficult to replicate in humans using sunscreen under normal conditions (Chipps 2016).

References

• Green A, Williams G, Neale R et al. 2011. Reduced melanoma after regular sunscreen use: randomized trial follow-up. Journal of Clinical Oncology 29(3): 257–263.
• van der Pols JC, Williams GM, Pandeya N et al. 2006. Prolonged prevention of squamous cell carcinoma of the skin by regular sunscreen use. Cancer Epidemiology Biomarkers & Prevention 15(12): 2546–2548.
• Thompson SC, Jolley D, Marks R. 1993. Reduction of solar keratoses by regular sunscreen use. New England Journal of Medicine 329: 1147–1151.
• Hughes MCB, Williams GM, Baker P, Green AC. 2013. Sunscreen and prevention of skin aging: a randomized trial. Annals of Internal Medicine 158(11): 781–790.
• Hanrahan JR. 2012. Nanotechnology in sunscreen formulations. Journal of Cosmetic Dermatology 11(3): 165–169.
• Dunton-Rose M, et al. 2014. Liposomal sunscreen formulations and skin protection. International Journal of Cosmetic Science.
• Rouleau D. 2021. Physical vs chemical sunscreens: formulation and skin tolerance. Dermatology Review.
• Chipps LK, et al. 2016. Sunscreen use and sun protection behaviour. Journal of the American Academy of Dermatology.
• Cancer Council Australia. 2020. Sunscreen and sun protection guidelines. Cancer Council Australia.
• Diaz A, Neale RE, Kimlin MG, Jones L, Janda M. 2012. Children’s sunscreen application: comparison of pump dispensers, squeeze bottles and spray formulations. Archives of Dermatology 148(11): 1316–1322.
• Therapeutic Goods Administration (TGA). 2020. Sunscreens and nanoparticles. Australian Government Department of Health.