Ultraviolet (UV) radiation is a carcinogen, period. UV damage comes from the sun. It is well established that excessive sun exposure causes skin cancer. Sunscreen-wise is to know some important facts about UV radiation and sunscreen efficacy as follows:
1. Understand how sunscreens/sunblocks work. Briefly, a sunscreen can filter UV radiation from sunlight. A sunblock, on the other hand, reflects or scatters the UV rays away so that it doesn’t reach the skin at all, which is preferable.
2. Be mindful about UVA.
a) UVA exposure of human skin mainly produces free radicals, which lead to DNA damage, cell and tissue injury, and consequently skin cancer.
b) UVA alters immune function, and it is primarily responsible for skin aging.
c) Over 90% of UV radiation is UVA, and it penetrates the skin deeper than UVB.
3. Clear up any confusion on SPF (i.e., sun protection factor). SPF is a number that you can use to help determine how long you can stay in the sun before getting a sunburn, and sunburn is caused by UVB radiation. Likewise, SPF measures how effectively the sunscreen formula limits skin exposure to UVB rays. The higher the SPF, the more protection the sunscreen provides against UVB rays; which is only meaningful within the range of 1 to 45, as science has shown. Currently, there is no uniform measure for UVA protection or absorption.
4. Now you know what to look for when choosing a product for sun protection. Remember: The degree of UVA filtration determines the quality of overall UV protection, whereas the number of SPF indicates the quantity of UVB protection.
5. Practice sun protection and know why. The use of sunscreen/sunblock plays a role in skin cancer prevention, esp. melanoma prevention.
In comparison, sunscreen-abuse is to use a sunscreen in order to allow a person to stay in the sun too long. Although sunburns may be prevented, skin cells are on their way to malignancy. This especially happens when a product is inadequately used, or no longer effective or with incomplete UV spectrum protection. In one word, sunscreen-abuse can compromise sun safety and skin protection.