The higher the SPF of sunscreen, the better?

That is not the case.

The sun protection factor of sunscreen, also known as the sun protection factor (SPF), is an indicator to measure its ability to protect against ultraviolet rays, but the higher the better is not necessarily the case.

First, it is important to know that the SPF value indicates how long the sunscreen can extend the time the skin can be exposed to the sun without getting burned. For example, a sunscreen with SPF 30 can extend the skin's exposure to the sun by 30 times, while a sunscreen with SPF 50 can extend it by 50 times. However, a higher SPF value does not mean a proportional increase in protection. For example, SPF 30 blocks about 97% of UVB rays, while SPF 50 blocks about 98% of UVB rays, so the difference between the two is not that big.

Although high SPF sunscreen can provide slightly stronger UVB protection, it may also bring some side effects. For example, products with high SPF values ​​are usually thicker in texture, may be more greasy, and are not easy to apply evenly, affecting the skin feel and usage experience.

When choosing a sunscreen, you should also consider your skin type, the environment in which you are active, and the amount of time you are exposed to the sun. For daily activities, using a sunscreen with an SPF of around 30 is generally sufficient to provide good protection. For long-term outdoor activities, such as at the beach or on the plateau, you can choose a sunscreen with an SPF of 50.

In addition, sun protection does not only rely on the SPF value of sunscreen. Correct use, such as applying it 15 to 30 minutes before going out, reapplying it every two hours, and choosing a sunscreen suitable for your skin type, can effectively protect the skin from UV damage. At the same time, combining other sun protection measures, such as wearing long-sleeved clothing, hats, and sunglasses, is also an important sun protection strategy.

Author: Tang Jiaoqing, MD, attending physician of dermatology

Review | Feng Jun, deputy chief physician of the Dermatology Department of Sinopharm Tongmei General Hospital