Prevention » Information Sheets » Sunscreen

Sunscreen

Prevention » Information Sheets » Sunscreen

Sunscreen

Cancer Council ACT recommends people us at least an SPF 30 broad-spectrum, water resistant sunscreen.

However, sunscreen should not be used to extend the time you spend in the sun, and should always be used in combination with other sun protection measures: shade, clothing, hats and sunglasses. Sunscreen should not be used as your only line of defence against UVR.

Cancer Council ACT recommends people us an SPF 30 or higher broad-spectrum, water resistant sunscreen. However, sunscreen should not be used to extend the time you spend in the sun, and should always be used in combination with other sun protection measures: shade, clothing, hats and sunglasses. Sunscreen should not be used as your only line of defence against UVR.

What does ‘SPF’ on a sunscreen label mean?

SPF stands for ‘sun protection factor’. Sunscreens with an SPF rating of 4 and above are listed on the Australian Register of the Therapeutic Goods Administration (TGA). 1 Products can only be listed on the register if they comply with the Australian/New Zealand Standard for sunscreen products (AS/NZS 2604). 2

The highest SPF for sunscreen available in Australia is now SPF50+.

The SPF number is only a guide to its strength. How long a person will take to burn depends on the time of day, the time of year, the amount of reflection, how cloudy it is and their skin type etc. It is almost impossible to calculate all these things in everyday situations.

In laboratory conditions SPF30+ sunscreen filters around 96.7% of UV radiation (if applied correctly), whilst SPF50+ will filter around 98%. However, many Australians apply too little sunscreen and do not reapply. This means they usually get less than half the protection stated on the product label. 3

What does ‘broad spectrum’ mean?

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 roughening, and also contributes to skin cancer.

UVB radiation penetrates the top layer of skin and is the main cause of sunburn that leads to skin damage and skin cancer. Broad spectrum sunscreen filters both UVA and UVB radiation from reaching important cell layers.

What’s in sunscreen and how does it work?

Sunscreens contain ingredients that absorb and reflect UV radiation. Examples include:

  • octyl methoxycinnamate (OMC): a prime UVB filter.
  • methylbenzylidene camphor: a prime UVB filter.
  • butyl methoxycinnamate: a prime UVA filter.

Some ingredients reflect UV radiation. Examples include:

  • zinc oxide: a prime UVA and UVB filter.
  • titanium dioxide: a prime UVA and UVB filter.

These last two ingredients are less likely to cause skin irritation as they work as a ‘physical’ barrier and sit on the skin.

Is sunscreen safe to use?

Yes. The United States Department of Health and Human Services ‘Eleventh Report on Carcinogens’ 4 lists compounds that have been proven to cause cancer. This list is updated frequently and has never included the chemicals found in sunscreen such as titanium dioxide, zinc oxide or OMC (octyl methoxy-cinnamate). There is currently no scientific evidence showing long-term side effects from regular use of sunscreen. 5

However we do know that UV radiation from the sun causes skin cancer. It is therefore important to protect ourselves from UV radiation using a combination of sun protection measures, including SPF 30+ or higher broad spectrum, water resistant sunscreen.

In 2012 the Eurpoean Commission Scientific Committee on Consumer Safety concluded on the basis of available evidence that the use of ZnO nanoparticles (as a concentration up to 25%) as a UV filter in sunscreen can be considered not to pose a risk of adverse effects in humans after dermal application.

The current weight of scientific evidence suggests that topically applied (insoluble) titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles (NPs) do not reach skin cells; rather, they remain on the surface and outer layer of the skin and therefore the risk they pose is negligible. 8,9  However, it is likely that sunscreen nanoparticles can penetrate the stratum corneum (outermost layer of skin) if applied to damaged skin. 7

Cancer Council sunscreens do not contain nanoparticles, however nanotechnology has beeen used in sunscreens for many years with no reports of adverse affects. Cancer Council continues to review research and to be guided by the Therapuetic Goods Authority, however at this time there is no conclusive evidence that justifies removing nanoparticle sized minerals from sunscreen.

In 2013, the TGA updated their review of the scientific literature in relation to the use of nanoparticle TiO2 and ZnO sunscreens. As in the previous review,  it was determined that antioxidant compounds/coatings used in sunscreen prevent TiO2 from generating reactive oxygen species (ROS), and that TiO2 and ZnO do not penetrate the skin to a degree where they pose a health risk. 7

Which sunscreen should I use?

Sunscreen can be bought as a cream, lotion, milk, spray or gel. All sunscreens labelled SPF 30+ or higher broad spectrum work well if applied corectly. Price is not always an indication of quality. Choose the one that best suits your skin type and your type of activity.

If you have sensitive skin and have had a reaction to a sunscreen, try a fragrance-free product. If you don’t want sunscreen residue left on your hands, a gel may work best for you.

Not all sunscreens contain the same ingredients. If your skin reacts to one sunscreen, talk to a chemist or doctor about choosing another with different ingredients.

SPF 30+ VS SPF 50+

In 2012, the revised AS/NZS 2604:2012 for sunscreen was announced. Raising the sun protection factor (SPF) limit was the decision of a panel of experts who deliberated its public health benefits and technical requirments. Combined with several other introduced measures, the new SPF 50+ sunscreen will offer Australians a greater level of protection, and be on par and consistent with international sunscreen standards.

Under the new standard (AS/NZS 2604:2012) effective 9 November 2012, sunscreens meeting TGA testing standards may be labelled as SPF50+, whereas previously SPF30+ was the highest level of protection manufacturers were able to claim. Sunscreens labelled between SPF15-SPF29 may no longer claim to be 'high protection', as this category is now assigned to sunscreens between SPF30-50. Only SPF50+ sunscreens may be labelled 'very high protection'.

Whilst Cancer Council supports the new increased SPF, it also reminds people that the actual increase in protection from SPF 30+ to an SPF 50+ is relatively small. Users are also reminded that it is important that sunscreen is applied correctly, and reapplied, to reach its full potential when it comes to reflecting and/or absorbing UV radiation from the sun.

Applying sunscreen correctly

Randomised studies conducted in Nambour, Queensland have shown that when sunscreen is used regularly, it is effective in reducing melanoma and squamous cell carcinoma (SCC)5 , but not basal cell carcinoma (BCC). 6

Apply sunscreen liberally (say 15 -20 minutes before you go outside). Apply sunscreen liberally – at least a teaspoon for each limb, front and back of the body and half a teaspoon for the face, neck and ears.  For example: the average-sized adult should apply at least a teaspoon of sunscreen to each arm, leg, front of body and back of body and at least half a teaspoon to the face (including the ears and neck). That is approx 35 ml of sunscreen for one full body application.

Reapply sunscreen every 2 hours, more often is washed or wiped off, and never use sunscreen to extend time in the sun!  Always combine sunscreen with other sun protection measures.

For more information read the label.

Sunscreen and photo-ageing

Sunscreen use is also protective against solar keratoses 10 and photo-ageing (premature skin ageing due to sun exposure such as wrinkles and skin discolouration). 11

How long can you keep sunscreen?

Check the expiry date and storage conditions on the label. Most sunscreens will last about two or three years. They should be stored at a temperature less than 25ºC. Avoid storing in excessive heat (for example, in the glovebox of a hot car or in the sun on the beach), over time, the product will not work as well.

If outdoors, reapply sunscreen every two hours (whether or not the label tells you to do this). Sunscreen can be easily wiped or sweated off. Putting on more sunscreen every two hours helps keep you protected. Do not use sunscreen to extend your time in the sun!

Sunscreen and babies

The Australasian College of Dermatologists does not recommend the widespread regular use of chemical sunscreens in very young babies (ie less than six months of age), as they absorb more of any chemical applied to the skin than adults. Sunscreens should be applied to areas of the skin not protected by clothing. 12 The American Academy of Pediatrics (AAP) 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.15

Ideally babies and toddlers should be kept out of the direct sun (ie when UV levels are 3 and above) or if this is not possible well-protected by using other forms of sun protection when UV levels are 3 and above including sensible clothing and shade so that sunscreen use is kept minimal.

Many brands of sunscreen have a babies or toddlers formula. These are just as protective, but much gentler on sensitive skin. Sunscreens with titanium dioxide or zinc oxide work largely by reflecting the UV radiation away from the skin, and are less likely to cause problems with sensitive skin. Sunscreen formulations composed primarily of inorganic/physical filters do not penetrate as deeply into the skin, 13 which makes them less likely to cause irritation/sensitisation. 14

Test the sunscreen on a small area of the baby or toddler’s skin before using it to make sure there won’t be any reaction.

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.

Further information and resources

This information is based on current available evidence at the time of review. For further information or advice contact Cancer Council 13 11 20.

This information can be photocopied for distribution.

References

1. Therapeutic Goods Administration. Australian Regulatory Guidelines for OTC Medicines: Sunscreens. Canberra: Commonwealth Department of Health and Ageing. 2003.

2 Australian/New Zealand Standard, AS/NZ 2604:1998. Sunscreen Products – Evaluation and Classification.

3 Stokes RP, Diffey BL. How well are sunscreen users protected? Photodermatol Photoimmunol Photomed 1997;13(5–6): 186–8.

4. Department of Health and Human Services Public Health Service. U.S. Department of Health and Human Services, Public Health Service National Toxicology Program. Report on Carcinogens. Research Triangle Park, NC, USA; 2011.

5. Green AC, Williams GM, Logan V, Strutton GM. Reduced melanoma after regular sunscreen use: randomized trial follow-up. J Clin Oncol 2011 Jan 20;29(3):257-63 [Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/21135266].

6. Green A, Williams G, Neale R, Hart V, Leslie D, Parsons P, et al. Daily sunscreen application and betacarotene supplementation in prevention of basal-cell and squamous-cell carcinomas of the skin: a randomised controlled trial. Lancet 1999 Aug 28;354(9180):723-9 [Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/10475183].

7. Therapeutic Goods Administration. Literature review on the safety of titanium dioxide and zinc oxide nanoparticles in sunscreens. Canberra, Australia: Commonwealth Department of Health and Ageing; 2013 Available from: http://www.tga.gov.au/industry/sunscreens-nanoparticles-review-2013.htm.

8. Cross SE, Innes B, Roberts MS, Tsuzuki T, Robertson TA, McCormick P. Human skin penetration of sunscreen nanoparticles: in-vitro assessment of a novel micronized zinc oxide formulation. Skin Pharmacol Physiol 2007;20(3):148-54 [Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/17230054].

9. Schilling K, Bradford B, Castelli D, Dufour E, Nash JF, Pape W, et al. Human safety review of "nano" titanium dioxide and zinc oxide. Photochem Photobiol Sci 2010 Apr;9(4):495-509 [Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/20354643].

10. Thompson SC, Jolley D, Marks R. Reduction of solar keratoses by regular sunscreen use. N Engl J Med 1993 Oct 14;329(16):1147-51 [Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/8377777].

11. Hughes MC, Williams GM, Baker P, Green AC. Sunscreen and prevention of skin aging: a randomized trial. Ann Intern Med 2013 Jun 4;158(11):781-90 [Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/23732711].

12. Australasian College of Dermatologists. A-Z of skin: Sun Protection & Sunscreens. [homepage on the internet] ACD; 2016 [cited 2017 Jan 10]. Available from: https://www.dermcoll.edu.au/atoz/sun-protection-sunscreens/

13. González S, Fernández-Lorente M, Gilaberte-Calzada Y. The latest on skin photoprotection. Clin Dermatol 2008 Nov;26(6):614-26 [Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/18940542].

14. Cross SE, Innes B, Roberts MS, Tsuzuki T, Robertson TA, McCormick P. Human skin penetration of sunscreen nanoparticles: in-vitro assessment of a novel micronized zinc oxide formulation. Skin Pharmacol Physiol 2007;20(3):148-54 [Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/17230054].

15. American Academy of Pediatrics. Policy statement: ultraviolet radiation: a hazard to children and adolescents. AAP 2011 Mar 3;127(3):588-97 [Abstract available at http://pediatrics.aappublications.org/content/127/3/588.full.pdf+html].

    1 Therapeutic Goods Administration. Australian Regulatory
    Guidelines for OTC Medicines: Sunscreens. Canberra:
    Commonwealth Department of Health and Ageing. 2003.
    2 Australian/New Zealand Standard, AS/NZ 2604:1998. Sunscreen
    Products – Evaluation and Classification.
    3 Stokes RP, Diffey BL. How well are sunscreen users protected?
    Photodermatol Photoimmunol Photomed 1997;13(5–6): 186–8.
    4 U.S. Department of Health and Human Services, Public Health
    Service, National Toxicology Program. Report on Carcinogens,
    Eleventh Edition. Research Triangle Park, NC: USDHHS, 2005.
    5 Marks R. Sunscreens: Questions and Answers. Sydney: Australian
    Cancer Society, 1993.
    6 Sullivan JR. A–Z of Skin: Baby and Toddler Protection. Australasian
    College of Dermatologists, 2001. Retrieved from http://
    www.dermcoll.asn.au/public/a-z_of_skinbaby_toddler_protection.asp
    on 31 October 2006.1 Therapeutic Goods Administration. Australian Regulatory Guidelines for OTC Medicines: Sunscreens. Canberra: Commonwealth Department of Health and Ageing. 2003. 2 Australian/New Zealand Standard, AS/NZ 2604:1998. Sunscreen Products – Evaluation and Classification. 3 Stokes RP, Diffey BL. How well are sunscreen users protected? Photodermatol Photoimmunol Photomed 1997;13(5–6): 186–8. 4 U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program. Report on Carcinogens, Eleventh Edition. Research Triangle Park, NC: USDHHS, 2005. 5 Marks R. Sunscreens: Questions and Answers. Sydney: Australian Cancer Society, 1993. 6 Sullivan JR. A–Z of Skin: Baby and Toddler Protection. Australasian College of Dermatologists, 2001. Retrieved from http:// www.dermcoll.asn.au/public/a-z_of_skinbaby_toddler_protection.asp on 31 October 2006.
Last updated February 2017