Summer is coming, so get your sunblock out. Note that I said “sun-block,” not “sun-screen.”
What’s the difference? Sun-blocks have physical barriers between your skin and the ultra-violet rays of the sun. Sunscreens depend mostly on chemicals to protect your skin from UV, and the chemicals have to permeate your skin first to work.
According to my dermatologist, sun-screens alone are useless. Your skin still gets exposed to UV even when you use them. You must use a sunblock, such as Titanium Dioxide (TiO2) or Zinc Oxide (ZnO). Apply liberally and every day you swim in the sun.
There is one other problem with using sunscreens with only chemicals. Some chemicals are harmful to aquatic life. Go to https://www.huffpost.com/entry/hawaii-ban-sunscreen-chemicals_n_5ae93604e4b022f71a02fc48 and see.
Some sun-blocks combine TiO2 and/or ZnO with chemicals. Check the list of chemicals, however, and NEVER use oxybenzone or octinoxate. Even if you only swim in a pool, such water eventually ends up in the sewers and possibly rivers and salt water. Protect yourself this summer, and other aquatic creatures.