In a bid to protect people from skin damage caused by too much exposure to the sun, health experts recommend using sunscreen products, which help protect the skin from ultraviolet radiation that could otherwise damage it, causing the skin to age prematurely and increasing a person's risk for skin cancer.

With the number of available sunscreen products for sale, consumers can be overwhelmed deciding which one to choose. The U.S. Food and Drug Administration recommends regularly using products with broad spectrum SPF values of at least 15.

The SPF, or sun protection factor, is the measure of the sunscreen's ability to protect the skin from UVB, the short wave ultraviolet B (UVB) rays which primarily cause sunburn. SPF is used to tell how long it will take to sunburn the skin that was treated with sunscreen compared with skin that was not treated with sunscreen.

Broad-spectrum lotions offer protection against both ultraviolet B radiation (UVB) and ultraviolet A radiation (UVA). While sunburn is primarily caused by UVB rays, the UVA rays are considered the culprits in premature skin aging.

The best sunscreen is supposed to have the highest SPF number. A sunscreen with SPF of 30 provides more protection compared with one with an SPF of 15 but it does not mean that the protection provided by the SPF 30 product against UVB rays is twice as much as that of the SPF 15 product.

It also means that sunscreen products with SPF number of more than 50 only provide a small increase in protection. SPF 15 products, in particular, filter out 93 percent of UVB rays. SPF 30 products provide protection against 97 percent and SPF 50 product only keeps out 98 percent of incoming UVB rays.

The American Cancer Society's recommendation is that people use sunscreen with an SPF number of at least 15. The American Academy of Dermatology recommends SPF 30. Experts advise against using sunscreens with SPF numbers that are higher than 50. Rather than looking for sunscreens with a very high SPF number, experts recommend applying sunscreen generously.

If your skin typically gets sunburned after 10 minutes, wearing an SPF 15 sunscreen would, in theory, allow you to stay under the sun for 150 minutes, or 10 x 15, without getting burned. The SPF model, however, has a problem because regardless of the strength of sunscreens, they are not effective for longer than two hours and thus require reapplication.

The sunscreen should also be applied thickly, and thoroughly enough to be effective. They can also be washed off during sweating or swimming and thus may not provide enough protection, regardless of the SPF number. Experts likewise recommend reading labels. 

"It is important for consumers to read the entire label, both front and back, in order to choose the appropriate sunscreen for their needs," said Lydia Velazquez, PharmD, from the Division of Nonprescription Regulation Development of the FDA.

ⓒ 2021 All rights reserved. Do not reproduce without permission.