Here is the truth on SPF protection in suntan lotions so you don’t waste your money on false claims of SPF protection.
First, if you didn’t know because you just hear it called SPF so often and nothing else, means Sun Protection Factor.
If you are going to the beach, out on the water, or just outside, you will see in the stores now an arsenal of SPF lotions and oils on the market now. Some of them go all the way up to a SPF 100. Also, you may notice the higher the SPF, many times the higher the cost.
Many doctors will say this about SPF protection and studies to have shown this:
Sunscreens with a higher SPF should offer more protection from the sun’s harmful ultraviolet (UV) radiation, which is linked to the clear majority of skin cancers, as well as premature skin aging and eye damage. Though that answer is not as easy as that.
An SPF 15 sunscreen blocks 93 percent of UVB radiation, while an SPF 30 sunscreen blocks nearly 97 percent. Furthermore, higher SPF values offer some safety margin, since consumers generally do not apply enough sunscreen. First, above SPF 50 (which blocks an estimated 98 percent of UVB rays), the increase in UVB protection is minimal. Second, although UVA protection is also important (UVA not only accelerates skin aging, but contributes to and may even initiate skin cancers), SPFs mainly measure UVB protection. Individuals applying high-SPF sunscreens may not burn (UVB is the chief cause of sunburn), but without UVA-screening ingredients they can still receive large amounts of skin-damaging radiation. To avoid such a scenario, regulatory bodies in Europe and Australia have adopted UVA testing guidelines and measurement standards, and capped the SPF of sunscreens at 50+. The US Food and Drug Administration (FDA) may do the same, but hasn’t to date.
Products with very high SPFs may also encourage individuals to neglect other photoprotective behaviors, like seeking the shade and wearing sun-protective clothing. By preventing sunburn, sunscreens with very high SPFs can create a false sense of security, prompting consumers to stay out in the sun longer. Sun damage (for example, UVA damage) can take place without skin-reddening doses of UV radiation, and even the best sunscreens should be considered just one vital part of a comprehensive sun protection regimen.
Ok, am sure you are thinking, just get to the point, so here it is. Sunbathers often assume that they get twice as much protection from SPF 100 sunscreen as from SPF 50. In reality, the extra protection is negligible. Properly applied SPF 50 sunscreen blocks 98 percent of UVB rays; SPF 100 blocks 99 percent. When used correctly, sunscreen with SPF values in the range of 30 to 50 will offer adequate sunburn protection, even for people most sensitive to sunburn.
High-SPF products may not really be high-SPF. When Procter & Gamble tested a competitor’s SPF 100 product at five different labs, the results varied between SPF 37 and SPF 75. The company determined that a very small difference in testing conditions can have a dramatic influence on the calculated SPF. In this case, a 1.7 percent change in light transmission yields a SPF measurement of 37 instead of 100. Small difference in application thickness could have a similar effect. Because of the way SPF values are calculated, these errors would be most dramatic for high-SPF products.
The FDA has long contended that SPF higher than 50 is “inherently misleading”. Australian authorities cap SPF values at 30; European and Japanese regulators at 50 and Canada allows a maximum of “50+”. In 2011, the FDA proposed a regulation to prohibit labels higher than SPF 50+, but the agency has not completed work on this rule and put it into force.
All you need and should stay safe is the SPF 30 to 50 for adequate protection.