The debate over sunscreens is heating up, mostly over the pros and cons of the two sunscreen formula types - physical and chemical.
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As well as the physical vs. chemical debate, there are other aspects relating to sunscreens under the spotlight. For instance, there is concern about the environmental impact of sunscreen ingredients, and the potential harm to humans from over-exposure to these substances.
On the other side of the argument, there are experts in the field of skin cancer who insist that the evidence is not conclusive, and that the potential harm does not outweigh the risk of not using sunscreens.1 One fact can be proved conclusively is that by following accepted sun protection guidelines, including the use of broad-spectrum sunscreen when UV levels are high, you will greatly reduce your risk of developing skin cancer.2
Physical sunscreens work by deflecting UV rays, whereas chemical versions work to absorb them. The category a sunscreen fits into can usually be determined by looking at the viscosity (thickness) of the sunscreen formula, and the ingredients listed on the product packaging.
Physical sunscreens are usually a thick white cream which includes ‘reflectors’ like zinc oxide or titanium dioxide in the ingredients. Because of the inclusion of these ingredients, physical sunscreens tend to create a ‘ghost’ effect on the skin, giving wearers a fairer complexion than they have naturally.
A huge positive from the whitening effect of physical sunscreens is that parents can see exactly where the sunscreen has been applied, ensuring skin surfaces are covered properly before sending their kids out into the UV rays. On the other hand, the thicker consistency of physical sunscreens can be an issue for oily or acne-prone skins.
Chemical sunscreens typically contain Octylcrylen, Avobenzone or Octinoxate - or a combination of these substances. They are in general thinner, easier to apply and more transparent than physical sunscreens. Although these formulations can sometimes be irritating for those with sensitive skin, they are generally considered to be more comfortable to wear due to their ability to let the skin breathe.
There are some concerns about potential free radical damage resulting from long-term use of chemical sunscreens, however most modern formulas contain antioxidants to help to safeguard your health.
Physical and chemical sunscreen formulas can be combined to create a very high SPF (Sun Protection Factor) broad-spectrum sunscreen. These formulations can be a good option, providing the benefits from both technologies, and reducing the negative effects.
So, what can we conclude?
When comparing chemical and physical sunscreens, it becomes clear that both have strengths and weaknesses, and there are some concerns about some of the ingredients used. From a scientific point-of-view there appears to be no clear winner in terms of which type of sunscreen is superior. It’s a personal decision that requires you to weigh up the unique needs of your skin and lifestyle.
1. Farberg, A. S., Glazer, A. M., Rigel, A. C., White, R., & Rigel, D. S. (2017). Dermatologists’ perceptions, recommendations, and use of sunscreen. JAMA dermatology, 153(1), 99-101. 2. Lazovich, D., Vogel, R. I., Berwick, M., Weinstock, M. A., Warshaw, E. M., & Anderson, K. E. (2011). Melanoma risk in relation to use of sunscreen or other sun protection methods. Cancer Epidemiology and Prevention Biomarkers, 20(12), 2583-2593.
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