National Sunscreen Day Date in the current year: May 27, 2024

Without the Sun’s light and heat, there would be no life on Earth. However, the ultraviolet radiation in sunlight has both positive and negative effects on human health. On the one hand, it stimulates the synthesis of vitamin D, which our body needs to absorb certain nutrients. On the other hand, short-turn overexposure to sunlight causes sunburn, and long-term UV exposure may cause premature skin aging (photoaging) and skin cancer.

People have been looking for ways to protect their skin from sun damage since ancient times, but modern sunscreen is a relatively recent invention. The first filters that protect from UVB (medium-wave) radiation were produced in 1929, and the first sunscreen was invented by Australian chemist H. A. Milton Blake in 1932. It was based on a 10% solution of phenyl salicylate (salol).

There are two main type of photoprotective agents used in modern sunscreens: inorganic and organic. Inorganic active ingredients of sunscreens, also known as physical or mineral, reflect, scatter, and absorb UV radiation. Common physical sun protection agents include titanium dioxide and zinc oxide. Organic (chemical) agents absorb UV light; they are usually derived from petroleum. The most common organic active ingredients found in sunscreens are oxybenzone, homosalate, and octocrylene.

The efficiency of sunscreens is measured by the so-called sun protection factor (SPF). It is a number that reflects the fraction of sunburn-producing ultraviolet radiation that reaches the skin once sunscreen is applied. For example, SPF 30 means that 1/30 of UV radiation will reach the skin, assuming sunscreen is applied properly.

Modern sunscreens ensure reliable protection against sunburn, photoageing and even skin cancer, but, sadly, most people don’t use them enough. There is a common misconception that you should wear sunscreen only when it’s sunny and hot outside. In reality, you need to wear it whenever the sun is in the sky, even if the weather is cold or cloudy. Another misconception is that people with dark skin don’t need to wear sunscreen. While people with fair skin are indeed more susceptible to sunburn and skin cancer, everyone needs protection from the sun.

National Sunscreen Day was created to highlight the importance of sunscreen and sun protection in general. It is a part of National Safe Sun Week, which is observed annually during the week before Memorial Day. As Americans tend to spend the Memorial Day weekend outside, enjoying warm weather and the sun, it is the perfect time to remind them of the dangers of sun exposure.

You can observe National Sunscreen Day by learning more about UVA and UVB radiation, different types of UV filters used in sunscreens and SPF levels, making a commitment to apply sunscreen (and use other sun protection measures) whenever you go outside, getting a skin cancer screening if you’re in a risk group, and spreading the word on social media with the hashtags #NationalSuncreenDay, #SunscreenDay and #SunscreenProtectionDay.