According to the Royal Pharmaceutical Society, the general public is confused by what sunscreen ratings really mean because of the dual rating system. The organization conducted a study that looked at 2,000 adults in the UK and discovered that about 20% did not realize that SPF ratings do not protect solely against all sun damage. SPF ratings actually only refer to the damaged caused by UVB rays. UVA ray protection is denoted on the labels via star rating which many people in the survey were unaware of.
UVA rays causes wrinkles and premature skin aging and both UVA and UVB rays can lead to the development of skin cancer says Igor Cornelsen in this article. Therefore, sun creams need to be rated highly against both types of rays, but most people mistakenly only look at the SPF rating and assume that both types are covered. This can be potentially harmful as UVA rays are actually able to penetrate into the skin at a deeper level leading to premature aging of the skin.
The survey discovered that only out of every three people actively looked at the UVA star rating before they purchased sunscreen. The star rating ranges from 0 to 5 and indicates how much sun is absorbed by the sunscreen.