The Benefits of Sunscreen
Sunscreen is one of the most effective ways of reducing exposure to ultraviolet (UV) radiation, the main cause of skin cancer. It has been proven to reduce the risks of melanoma1, squamous cell carcinoma2, and solar keratoses3. It has also been shown to reduce visible signs of skin ageing4.
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 the genes, either by absorbing or reflecting UV radiation.
Physical / Mineral Sunscreens
Physical sunscreens create a barrier on top of the skin which UV radiation cannot easily penetrate — it reflects off the skin. The active ingredients are usually zinc or titanium.5
Chemical sunscreens absorb UV radiation, converting it into heat which is released from the skin. There are many different formulations, often used in combination because each chemical protects against a narrow range of wavelengths.
Liposomal sunscreens are a relatively new formulation. Small particles contain the UV-blocking component of sunscreen. They absorb into the uppermost layer of the skin, rather than sitting on top of it (but they do not penetrate the skin or enter the bloodstream).
|Physical / Mineral||
Physical sunscreens protect from the time they are applied, and usually cause minimal irritation to sensitive skin.
Some physical sunscreens create a visible white film when applied, particularly on dark skin. Some can be thick, greasy and hard to apply. Physical sunscreens are more likely to rub or sweat off.6 Modern physical sunscreens contain very small nanoparticles of active ingredients which are less likely to create a visible film on the skin surface.
Chemical sunscreens are usually easier to apply and less visible than physical sunscreens. They are less likely to wash or sweat off.
They need to be applied about 20 minutes prior to sun exposure, to give sufficient time to work effectively. Chemical sunscreens are more likely to cause irritation to sensitive skin.6
Liposomal sunscreens might last longer, theoretically a whole day. Clinical studies have not yet proven this. You should reapply liposomal sunscreens just as you would any other sunscreen.7
|Some liposomal sunscreens are expensive.|
How to Choose a Sunscreen
Any sunscreen you use should have a sun protection factor (SPF) of at least 30, and provide broad spectrum protection.
Sun Protection Factor
Sun protection factor (SPF) is a measure of how much longer it takes skin to burn with sunscreen than without. A higher SPF number means stronger protection.
Properly applied, SPF 30 filters 96.7% of UV-B radiation, and SPF 50 filters 98%. The difference is relatively small and need not influence your sunscreen choice if there are other factors which are more important to you.
Broad Spectrum Sunscreens
UV radiation occurs in different wavelengths – UV-A and UV-B. A good sunscreen blocks a high proportion of both types. SPF only measures protection against UV-B which causes burning. UV-A causes longer-term changes such as wrinkling, drying and ageing of the skin. Both types of radiation contribute to skin cancer development.
Broad spectrum sunscreens protect against both wavelengths of UV radiation. In Australia, most commercially sunscreens with SPF30 or more provide broad spectrum protection, but you should always check that the label specifies “broad spectrum”.
If your sunscreen is broad spectrum and SPF 30 or more, other factors are a matter of personal preference. You should choose the sunscreen that you are most likely to use.
Things that might influence your choice:
If your skin is very sensitive, choose a sunscreen that is less likely to cause irritation. In general, physical sunscreens, “low irritation” sunscreens and sunscreens marketed for children or babies are less irritant
If your skin is dry, you may prefer a cream which combines sunscreen with moisturiser. Alternatively, you can use a very light or “sheer” sunscreen and then cover it with make-up or moisturiser.
Swimming and Sweating
If you are swimming or sweating while outside, a chemical sunscreen will usually last better. Some brands specifically formulate sunscreens for “wet skin” or “water sports”.
If you spend a long time in the sun, particularly if you sometimes forget to reapply, a longer-lasting formulation may be suitable. These include liposomal products, and others containing proprietary combinations of chemical sunscreen components formulated to break down more slowly, e.g. Helioplex in Neutrogena sunscreens.
Aerosol sprays are easy to apply and can be useful for hairy skin or children who might not tolerate having cream or lotion rubbed in to their skin.
These sprays should be applied outdoors where there is less chance of inhalation.8
Many affordable sunscreens are available in supermarkets and discount pharmacies. Some come in large containers suitable for family or workplace use.
If a sunscreen is labelled as SPF 30 or more, and broad spectrum, it should provide good protection providing it is properly applied.
Some people apply sunscreen and still get sunburnt. Sunscreens on the Australian market are tested to ensure they work as advertised. The most common cause of sunscreen “failure” is not applying it properly.8
Applying and Reapplying
- one teaspoon of sunscreen applied to the face/head/neck
- two teaspoons for the torso
- one teaspoon to each arm/forearm
- two teaspoons to each leg
Sunscreen should be applied 20 minutes before going outside and reapplied every two hours.11
Pump packs are a good way of ensuring adequate sunscreen is applied. Children using pump packs tend to apply more sunscreen than those using sprays or squeeze bottles.12
On a cloudy or cool day, it can be easy to forget to apply and reapply sunscreen. We recommend the SunSmart app for smartphones. It can notify the user when the UV index reaches a level which can damage skin, and remind when to reapply sunscreen.13
It’s common for people not to use enough sunscreen when using a spray-on formulation. Different brands deliver a different amount of sunscreen per second.11 To get adequate protection, ensure that you spray enough to feel wet, and then smear it in with your hand.8
Sunscreens should be stored below 30° and not used past their expiry date. Do not keep sunscreens in your car.
Sunscreen and Vitamin D Deficiency
Vitamin D deficiency is common in Australia. Since sun exposure is necessary to produce vitamin D, some people are concerned that using sunscreen may lead to low vitamin D levels. Studies have shown that this is not the case. There is no confirmed link between low vitamin D levels and sunscreen use.5
Potentially any sunscreen could cause problems; it’s not possible to conclusively prove that any product is 100 per cent safe. However, there is strong evidence that the health benefits of sunscreens far outweigh any health risks.
Some ingredients in sunscreens irritate sensitive skin. It can be a process of trial and error to find a sunscreen that causes the least irritation.
- Fragrances can cause irritation. Use unscented sunscreens where possible.
- Physical sunscreens are less likely to irritate the skin than chemical sunscreens.
Nanoparticles are very tiny (less than 100nm) particles of zinc or titanium used in some physical sunscreens. They reduce the white greasy appearance common with physical sunscreens and can be easier to apply. Nanoparticles have not been shown to penetrate the skin. There is no current evidence that they are absorbed into the bloodstream or cause any health problems.5, 14
Hormone Disruption and Cancer
Some people have raised concerns that the organic compounds (e.g. oxybenzone) used in chemical sunscreens could cause cancer or disrupt the action of hormones. To date, these effects have been seen only in animals during testing at extremely high doses. It would probably be impossible to replicate these doses in humans using sunscreen, even over many years.8
There’s no single “best” sunscreen for everyone in all situations. Use a broad spectrum product with SPF 30 or more, and apply it properly and regularly, and you should be well protected, and reduce your skin cancer risk. The “best” sunscreen for you, is the one you are most likely to use.
Sunscreen formulations change frequently. At the time of writing, our favourite is Cetaphil Sun SPF50+ Kids Liposomal Lotion, (even for adults) because of the following benefits:15
- Suitable for sensitive skin
- Highest level of protection
- Reasonable price (significantly cheaper than the “adult” liposomal formulation currently available in Australia)
- Excellent packaging: The pump pack provides measured quantities of sunscreen and there are clear instructions on how many pumps to use for each body part.
- Liposomal formulation may last longer between applications.
Disclaimer: This is general information only. Spot Check Clinic gives no guarantee that this product is superior in terms of protection, side effects, or in any other way, to other sunscreens. Notwithstanding our recommendation, Spot Check Clinic takes no responsibility for any adverse events that occur when using this product.
For more detailed information about sunscreens, see:
- Slevin, Terry. Sun, skin and health (CSIRO 2014). Chapter 5: “Slop on some sunscreen”: The mysteries and truth about sunscreen. www.publish.csiro.au/book/7227
- The Skin Cancer Foundation’s Guide to Sunscreens. www.skincancer.org/prevention/sun-protection/sunscreen/the-skin-cancer-foundations-guide-to-sunscreens
- 1. Green, A C, et al. Reduced melanoma after regular sunscreen use: randomized trial follow-up. [Online] 20 Jan 2011. [Cited: 20 Oct 2017.] https://www.ncbi.nlm.nih.gov/pubmed/21135266
- 2. van der Pols, Jolieke C, et al. Prolonged prevention of squamous cell carcinoma of the skin by regular sunscreen use. [Online] 15 December 2006. [Cited: 20 October 2017.] http://cebp.aacrjournals.org/content/15/12/2546
- 3. Thompson, Sandra C, Jolley, Damien and Marks, Robin. Reduction of solar keratoses by regular sunscreen use. [Online] 14 Oct 1993. [Cited: 20 Oct 2017.] http://www.nejm.org/doi/full/10.1056/NEJM199310143291602
- 4. Hughes, Maria Celia B, et al. Sunscreen and prevention of skin aging: a randomized trial. [Online] 4 Jun 2013. [Cited: 20 Oct 2017.] http://annals.org/aim/article/1691733/sunscreen-prevention-skin-aging-r…
- 5. a. b. c. Hanrahan, Jane R. Sunscreens. Australian Prescriber. [Online] 28 Sep 2012. [Cited: 24 Oct 2017.] https://www.nps.org.au/australian-prescriber/articles/sunscreens
- 6. a. b. Rouleau, Renée. Chemical vs. physical sunscreens: pros and cons. Renée Rouleau. [Online] 19 Jul 2017. [Cited: 24 Oct 2017.] http://blog.reneerouleau.com/chemical-vs-physical-sunscreens-pros-cons/
- 7. Dunton-Rose, Justine. Is liposomal sunscreen the answer to everything? Popsugar. [Online] 23 Oct 2014. [Cited: 24 Oct 2017.] https://www.popsugar.com.au/beauty/What-Liposomal-Sunscreen-35978840
- 8. a. b. c. d. Chipps, Lisa. Debunking myths on SPF and UPF clothing. Dermcast.TV. [Online] 2016. [Cited: 25 Oct 2017.] http://dermcast.tv/debunking-myths-on-spf-and-upf-clothing
- 9. Diffey, B L. People do not apply enough sunscreen for protection. BMJ. [Online] 12 Oct 1996. [Cited: 24 Oct 2017.] http://www.bmj.com/content/313/7062/942
- 10. Jovanovic Z et al. Conventional sunscreen application does not lead to sufficient body coverage. International Journal of Cosmetic Science [online] 11 Aug 2017. [Cited: 8 Jan 2018.] http://onlinelibrary.wiley.com/doi/10.1111/ics.12413/full
- 11. a. b. Cancer Council Australia. Sun protection. Skin cancer statistics and issues. [Online] 24 Jul 2017. [Cited: 24 Oct 2017.] http://wiki.cancer.org.au/skincancerstats/Sun_protection#Sunscreen
- 12. Diaz, Abbey, Neale, Rachel E and Kimlin, Michael G. The children and sunscreen study: A crossover trial investigating children's sunscreen application thickness and the influence of age and dispenser type. JAMA Dermatology. [Online] May 2012. [Cited: 24 Oct 2017.] https://jamanetwork.com/journals/jamadermatology/fullarticle/1149913
- 13. SunSmart Victoria. Free SunSmart app. SunSmart. [Online] 2017. [Cited: 25 Oct 2017.] http://www.sunsmart.com.au/tools/interactive-tools/free-sunsmart-app
- 14. Therapeutic Goods Administration. Sunscreens: information for consumers. Therapeutic Goods Administration. [Online] 29 Jan 2014. [Cited: 26 Oct 2017.] https://www.tga.gov.au/community-qa/sunscreens-information-consumers
- 15. Galderma Australia. Sun SPF50+ Kids Liposomal Lotion. Cetaphil Australia. [Online] [Cited: 24 October 2017.] https://www.cetaphil.com.au/product/sun-spf50-kids-liposomal-lotion/