Sun Protection Factor, otherwise known as SPF, was developed by Franz Greitier in the 1970s and is simply just a measure of the fraction of ultraviolet light that reaches the skin. For example, an SPF of 20 means that 1/20th of the ultraviolet will reach the skin with the recommended thickness of sunscreen applied.
When choosing a sunscreen, always make sure that your product states that it has broad-spectrum SPF protection or the harmful, non-burning rays from the sun will still get through to the skin’s cells. A broad-spectrum product with an SPF of 20 will only allow 1/20th of all ultraviolet light rays to reach the skin, including the more harmful ultraviolet type A light.
We know what you’re thinking……
How high of an SPF do you need to stay well protected?
Well, the most common SPF values typically seen on the market fall between 30 and 50 SPF as they respectively offer 97% and 98% protection from the sun’s UV rays. Anything higher than 50 SPF, even SPF 100, would only provide the tiniest minuscule of a fraction more protection compared to the protection a SPF 50 sunscreen already provides.
Another factor that determines SPF levels in products is that making products that are enjoyable to use with an SPF level above 50 SPF is pretty difficult. A 100 SPF product would be a thick white pasty tenacious mess to battle with on one’s skin, but can surprisingly also let more UVA rays pass through the sunscreen causing more damage to the skin when compared with a 50 SPF product. The types and number of chemicals needed to create an SPF rating of 100 typically do not have strong UVA blocking qualities and therefore may increase the risk of skin cancer development compared to a standard SPF 50 product.
The FDA, in 2019, proposed to cap SPF production at SPF 60 as sunbathers and beachgoers alike are often misled by associating higher SPF numbers with more protection.
We always recommend a broad-spectrum product made with non-nano zinc oxide and mostly natural ingredients with an SPF rating of at least 30 but less than 60.
- Dr. Thomas Macsay