Ask Dr. Schultz
Do I need to reapply waterproof sunscreen or sunblock?
Some people on the internet said that you don’t need to reapply sunblock as well as waterproof sunscreen, especially when you’re just sitting in the workplace all day. Is it true?
Hi Jess, thank you for posting your question. I created a DermTV about what water resistant sunscreens and what that really means: http://www.dermtv.com/are-water-resistant-sunscreens-really-water-resistant
On a practical level, I’m not sure that water resistant labeling is all that helpful. So regardless of the labeling on the sunscreen, to help minimize cosmetic and pre-cancerous sun damage, reapply your sunscreen immediately after swimming or sweating. Only then can you be assured of the labeled, if not optimal, sun protection.