Sunscreen and sunblock product labels can get really confusing for men. While most guys I know may be quick to point out that SPF stands for Sun Protection Factor, they do not realise the difference in protection it offers against the two main ultraviolet rays responsible for skin damage, which are ultraviolet A (UVA) and ultraviolet B (UVB). Most men are also clueless as to what PA+ indicated on a sunscreen label would mean.
For the benefit of these guys and all who wonder, let me explain what PA means. PA actually stands for Protection Grade of UVA, which is a protection measurement used in Japan. While SPF indicates how much a product can protect you from UVB, PA on the other hand refers to the amount of protection it offers against UVA rays. You might encounter products labelled as PA+, PA++ or PA+++. More plus symbols mean more protection from UVA.
UVA is a long wave UV ray (also known as “black light”) which is responsible for long-term skin damage, while UVB is a medium wave UV ray which causes the more acute sunburn (short term). In the past, UVA was considered less harmful, but today it is known that it can contribute to skin cancer via indirect DNA damage, by generating highly reactive chemical intermediates, such as hydroxyl and oxygen free radicals, which in turn can damage DNA. UVA penetrates deeply into the skin but it does not cause sunburn. It cannot be measured in SPF testing simply because it does not cause erythema or any reddening of the skin.
UVB on the other hand causes direct DNA damage, but this is easily recognised and automatically repaired by our body, resulting in increased pigment (melanin) production and a long-lasting tan. This tan occurs with a two-day lag phase after irradiation, but it is much less harmful and long lasting than the one resulting from UVA. However, do not be misled to think that UVB is any safer. Besides the usual sunburn, overexposure to UVB irradiation can also cause some forms of skin cancer.
There is another type of irradiation most people are not aware of, called ultraviolet C (UVC). This has the highest energy of all three, and is the most dangerous type of ultraviolet light. Little attention has been given to UVC rays in the past since they are mostly filtered out by the atmosphere of the earth. But we need to increase our awareness on UVC as the earth we live in slowly destroys itself.
So make sure you are using the correct sunscreen or sunblock when you are exposed to sunlight. The correct sunscreen or sunblock has to have an adequate amount of protection against both UVA and UVB rays. It is always good practice to read the labels carefully before purchasing your bottle of sunscreen.
