Can we really trust sunscreens?
Most Australian sunscreens overstate their SPF – yet sunlight is vital for our health.
Today, Choice has revealed that 16 out of 20 Australian sunscreens failed to deliver on their claimed sun protection factor (SPF) – calling into question our trust in labels and sun safety.
The tested products all claimed to be SPF 50+, meaning you’re 50 times less likely to be sunburned when wearing the sunscreen.
But is sunscreen the best protection from sun-induced skin damage? Are we over-protecting?
Why sunlight matters:
Sunlight is the body’s primary source of vitamin D, an essential nutrient for building strong bones1.
Vitamin D production via sunlight is dependent on ultraviolet B radiation (UVB), which makes up about 5% of UV radiation2.
Most UVB radiation comes from sunlight in the middle of the day, when your shadow is the shortest (typically between 10:30am and 1:30pm)3.
The skin needs UVB to convert 7-dehydrocholesterol into vitamin D3.
This vitamin D3 is then converted into its active form, calcitriol, a hormone which is essential for maintaining calcium and phosphorus balance in the body.
Beyond bone health, calcitriol reduces inflammation and oxidative stress. Evidence also shows that it protects against heart disease, type 2 diabetes, hypertension and some cancers.
Risks of excess sunlight
While UVB is essential for vitamin D synthesis, sunlight (including UVB and UVA) can also damage skin cells. The body offers some protection, by producing melanin.
Melanin is the pigment responsible for skin darkening (and sometimes producing freckles) after being in the sun.
Melanin absorbs UV radiation and neutralises free radicals, reducing the risk of DNA damage in skin cells4.
This protection fades over time as melanin-containing cells are naturally shed from the skin’s surface.
Why sunscreen is important
Some people produce more melanin, and are able to tolerate more sunlight before damaging the skin. These individuals also require more time in the sun to absorb UVB for vitamin D3 synthesis. Individuals with lighter complexions typically burn more easily, and synthesize vitamin D3 more readily.
Hence the need for additional sun protection, such as sunscreen.
Not all sunscreens are equal
Now, obviously sunscreens will vary in terms of the SPF they offer (and as shown by Choice, not all sunscreens deliver on their advertised protection). The other factor to consider is the ingredients, because whilst sunscreen may block UVB (and UVA which can also damage skin), the skin will absorb the sunscreen to an extent5. The evidence on just how much is absorbed by the skin is inconclusive and debatable.
If you’re interested in learning more on sunscreen ingredients and the skin’s system for protecting against damage from these, I will write a separate article soon as this deserves it’s own post.
So to bring it all together:
The results of Choice’s sunscreen test are concerning. We need reliable SPF labels and stronger regulation by the Therapeutic Goods Association (TGA).
Sunlight is important for health and blocking all sunlight may have other health consequences. The key is to understand how much sun your particular skin type can tolerate. The best approach is a balanced one: short, mindful sun exposure for your skin type, then cover up or apply a truly broad-spectrum sunscreen you can trust.
Some interesting recent peer-reviewed studies informing this article are listed below.
Whitney, E., Rolfes, S. R., & Crowe, T. (2022). Understanding Nutrition. Cengage Learning Australia.
Alfredsson, L., Armstrong, B. K., Allan Butterfield, D., Chowdhury, R., de Gruijl, F. R., Feelisch, M., Garland, C. F., Hart, P. H., Hoel, D. G., Jacobsen, R., Lindqvist, P. G., Llewellyn, D. J., Tiemeier, H., Weller, R. B., & Young, A. R. (2020). Insufficient sun exposure has become a real public health problem. International Journal of Environmental Research and Public Health, 17(14), pp. 1–15.
Wimalawansa, S. J. (2023). Infections and Autoimmunity—The Immune System and Vitamin D: A Systematic Review. Nutrients, 15(17). Multidisciplinary Digital Publishing Institute (MDPI).
Tortora, G. J., Derrickson, B., Burkett, B., Cooke, J., DiPetro, F., Diversi, T., Dye, D., Engel, A., Green, H., Macartney, M., McKean, M., Peoples, G., & Summers, S. (2021). Principles of Anatomy & Physiology (3rd ed.). John Wiley & Sons, Incorporated.
Scanlon, V. C., & Sanders, T. (2006). Essentials of Anatomy and Physiology (5th ed.). Davis Company.