(4) Is a higher SPF value and PA value better?
A: When buying sunscreen, don’t blindly pursue a high SPF. SPF50 only increases the UVB protection by less than 1% compared to SPF30. Moreover, products with high SPF and PA values are generally greasy, have poor application experience, and are prone to clog pores, leading to acne or folliculitis. Choose products with appropriate SPF, PA values, and waterproof capabilities according to your actual needs. For daily commuting, SPF15~30 and PA++ are sufficient. Don’t blindly pursue high indices.
(5) Is applying sunscreen once a day enough?
A: In summer, it’s easy to sweat and wash off sunscreen, so it’s recommended to apply sunscreen every two hours. When in environments with strong sunlight, such as the beach, sunscreen should be reapplied every 30 to 90 minutes. However, for daily commuting or indoor work, applying sunscreen once a day is completely sufficient.
(6) Do you need to apply sunscreen to the parts covered by a mask?
Regular medical masks have some sun protection effect (approximately SPF10, dark-colored masks provide slightly better sun protection than light-colored ones), but the sun protection ability is not sufficient, and light may leak through the gaps in the mask. Therefore, it’s still necessary to apply sunscreen to the entire face to avoid uneven skin tone. Visualize the sun exposure situation of people wearing non-woven masks containing materials that change purple due to UV radiation when exposed to UV lamps equivalent to the UV radiation in sunlight while wearing non-woven masks for a certain period of time.
(7) Can you get enough vitamin D by sunbathing indoors?
Unfortunately, no. Vitamin D3, closely related to calcium supplementation, is mainly synthesized by UVB radiation. Indoors, most of the UVB radiation is blocked by glass, so sunlight entering indoors through windows cannot be relied upon for calcium supplementation. It’s still advisable to go outside for a short period to sunbathe every day, avoiding intense sunlight at noon. The golden sunbathing hours are 9-10 am and 4-5 pm, and 10-20 minutes is sufficient.
