Tralia, the region with the highest rate of skin cancer globally.
In recent years, sunscreen hasn’t just become about avoiding skin cancer, but in keeping us young and preventing wrinkles. It has transformed into a 2-in-1 way to moisturize and protect your skin. And, as you learn more about the dangers of UV, it only becomes more important.
Understanding UV Radiation
UV radiation is a form of energy that is emitted by the sun. It reaches the Earth's surface through the ozone layer and has two main types of rays: UVA and UVB.
UVA rays have a longer wavelength and penetrate deeper into the skin, causing signs of skin aging such as fine lines and wrinkles. They can pass through glass and are present throughout the year, even on cloudy days. UVB rays though have a shorter wavelength, meaning they impact the outer layers of the skin and are responsible for sunburns.
Both UVA and UVB rays can cause DNA damage in skin cells. UVB is more intense during the summer months and at higher altitudes, while UVA levels remain relatively constant throughout the year.
The major takeaway here is that just because it’s winter and you’re not getting burnt, it doesn’t mean UVA rays aren’t causing harm. This is why sunscreen should be applied year round.
Types of UV Filters
Sunscreens can be placed into two main categories of UV filters: physical (mineral) and chemical (organic). Physical UV filters, such as zinc oxide and titanium dioxide, work by creating a protective barrier on the skin's surface. They reflect and scatter UV rays, preventing them from penetrating the skin. Mineral sunscreens for the face work with an immediate effect.
Chemical UV filters absorb UV radiation and convert it into harmless heat. Common chemical filters include octinoxate and oxybenzone. These filters typically take about 20 minutes to become effective after application.
The Science of SPF
A sunscreen’s sun protection factor (SPF) is a measure of how effectively it protects against UVB rays. It indicates how much longer it takes for UVB rays to cause sunburn on protected skin compared to unprotected skin. For example, SPF 15 filters out approximately 93% of UVB rays, while SPF 30 filters about 97%.
However, it's important to note that SPF doesn't directly relate to time spent in the sun. Factors such as skin type and the amount applied also affect protection levels. The British Association of Dermatologists recommends using sunscreen with at least SPF 30 and reapplying every two hours, regardless of the rating. Look for broad-spectrum sunscreens that protect against both UVA and UVB rays.
Emerging UV Filter Technologies
In recent years, nanoparticles that use minerals like zinc oxide and titanium dioxide have gained popularity due to their ability to provide broad-spectrum protection without leaving a white residue. Organic-inorganic hybrid filters are also emerging, combining the benefits of both types of UV filters.
While sunscreen developers face some tricky challenges, they’re currently focused on improving photostability, water resistance and aesthetics. Recent innovations are enhancing the stability of UV filters to maintain protection over extended periods of sun exposure.
Water-resistant formulations are being developed to ensure continued efficacy during swimming or sweating, while skin feel remains important for consumers. If it feels nice and absorbs easily, users are more likely to reapply.
Environmental and Health Considerations
Unfortunately, sunscreens do come at a cost to coral reefs, leading to bans on certain UV filters in some regions. Oxybenzone and octinoxate have been scrutinized for their potential harm to marine life when swimming or snorkeling, though this could be prevented by swimming first, and then applying sunscreen when out of the water. Some chemical UV filters have also been accused of having potential hormonal effects in humans.
The sunscreen industry is responding by developing more environmentally friendly formulations and promoting the use of mineral-based filters. It appears that, unless there are significant advancements among chemical formulas, we are pivoting in favor of mineral sunscreen as it’s a more natural product.
Comprehensive Sun Protection Strategies
While sunscreen is of course important for sun protection, it cannot be wholly relied upon without other steps in place. It’s important to know how much to apply in the first place and to continue reapplying every two hours, or after swimming or sweating.
Complementary protective measures shouldn’t be overlooked, such as UV-protected sun hoodies and wide-brimmed hats. Sunglasses with UV-blocking lenses can protect the eyes and surrounding skin too, and of course, nothing can beat simply seeking shade.
Conclusion
The field of sunscreen technology is far from its final state. With plenty of pending innovations, the current go-to option is mineral-based sunscreen. And, with the current technology, frequent reapplication and other considerations are necessary to stay safe from the sun.