How do Zinc-based sunscreens work to block UV rays?
- May 3, 2022
- 1 min read
Updated: Nov 15, 2024
To understand how sunscreens work, you must first understand what ultraviolet (UV) radiation is. UV radiation has a shorter wavelength than visible light, meaning it penetrates the skin and can damage DNA, causing mutations that lead to skin cancer. Visible light has a longer wavelength, while X-rays are on the other end of the spectrum with even shorter wavelengths than UV. As you can imagine, X-rays can penetrate through the body and stop when they hit bone; UV rays are just short of that and stop when they hit the first layers of skin.
UV is divided into two categories: UV-A and UV-B.
UV-A is to blame for long-term skin damage (sun spots, aging, wrinkles), while UV-B is to blame for sunburn and skin cancer. A good sunscreen is “broad spectrum” meaning it blocks both UV-A and UV-B rays.
Zinc oxide is one ingredient in organic sunscreens which blocks both UV-A and UV-B rays. The way it does this is by forming a physical barrier on the skin. This literally causes UV rays to bounce off, reflect, or scatter off of it. In some ways, it is like a layer of clothing. Therefore, the harmful UV rays are not absorbed into the skin! In contrast, the organic sunscreens containing chemicals such as oxybenzone absorb only UV-B rays and release the energy as heat.
In the old days, zinc-based sunscreens were known to form a white paste on the skin (hence their strong barrier function!). However, nanotechnology nowadays has made it possible to make cosmetically pleasing, but just as effective, zinc-based sunscreens that do not leave a white film on the skin.
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The discussion around sunscreen efficacy highlights the importance of ingredient selection. While zinc oxide remains a preferred choice for broad-spectrum protection, the complexities of chemical formulations raise questions. It is vital to understand that not all sunscreens are created equal, especially when it comes to the effectiveness against UV rays. The Pokies https://pokemoncards.io/ serve as a metaphor for the risks we take without proper knowledge.
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