For those of us living in the Northern Hemisphere now is the time of maximum danger from exposure to sunlight. Thank goodness for highly effective sunscreens. On June 9^th, the FDA approved a new chemical that filters ultraviolet rays—bemotrizinol (BMT). So, based on the experience of Europeans, who have used BMT for decades, those Americans who use sunscreen will soon be even better protected.

Unfortunately, many here in the USA either never use sunscreen (admitted by nearly third of all adults in a 2024 Yahoo News/YouGov 2024 survey) or they fall prey to these myths*:

• It is OK to skip sunscreen on cloudy days. “UV rays penetrate clouds,” says dermatologist Shari Lipner.
• Sunscreen is only needed if you are outdoors a long time. Lipner says “Incidental exposure adds up over time.”
• SPF in cosmetics protects you. Lipner says “it’s best viewed as a small bonus.”

Here are some suggestions on maximizing sunscreen effectiveness based on research reported in my July 1, 2018 blog post Are you seeing red sorting out how much sunscreen to apply and at what strength?:

• FDA statistics indicate that an SPF of 50 blocks 98% of UV rays versus 93.3% for a 15 SPF sunscreen. If SPF 50 is too pricey, consider downgrading to an SPF 30 offering 96.7% protection.
• To be effective, sunscreen must be applied to a thickness of at least 2 milligrams per square centimeter—about one-fifth the depth of a piece of paper. Although this seems very thin, most people only put on about half that amount, so you’d best apply your sunscreen twice. Doing so will also reduce the chances of missing exposed areas. This happened to me on a two-day paddle down the Saint Croix River bordering Minnesota and Wisconsin. I missed areas on my foot not covered by my water shoes and suffered painful burns on both ankles.

Bottom line: Go ahead and skip or skimp on sunscreen—your dermatologist’s boat payment depends on it. ; )

*Source: “How to Fight Sun Damage,” Consumer Reports, July-August, 2026 .