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The FDA considers zinc oxide and titanium dioxide to be the only safe sunscreens in existence. It allows a whitelist of about 10 chemicals to be sold as sunscre

The FDA considers zinc oxide and titanium dioxide to be the only safe sunscreens in existence. It allows a whitelist of about 10 chemicals to be sold as sunscreen. Everything else "doesn't have enough data" but there is evidence that many of the chemicals on the FDA sunscreen whitelist are endocrine disruptors. I appreciate that zinc oxide is a UVA blocker in addition to UVB. I always thought more SPF gave me more protection until I realized it does not measure UVA whatsoever. Turns out that depending on where you live if you are outside before 9:30 am and after 3:30 pm you won't get sunburned because the UV index is less than 3-5 at those times Windy has a new UV layer but I would trust a UV measuring device more. Just collect some sample readings over a few typical days to get a feel for the irradiation in your area so you can plan accordingly.

orangepurple 4y ago
One of the most interesting sunscreen metrics is mentioned completely unceremoniously on the last page of the Final Order Monograph 2020. It is sad that we don't have access to the critical wavelength value calculations described on the last page of Monograph M020. The critical wavelength is identified as the wavelength at which the integral of the spectral absorbance curve reaches 90 percent of the integral over the UV spectrum from 290 to 400 nm. A mean critical wavelength of 370 nm or greater is classified as broad spectrum protection. Sunscreen users could benefit from understanding the UV blocking performance of each sunscreen on the market. Reference: U.S. Food and Drug Administration Final Administrative Order (OTC000006) Over-the-Counter Monograph M020: Sunscreen Drug Products for Over-the-Counter Human Use (Posted September 24, 2021) https://www.fda.gov/drugs/understanding-over-counter-medicines/sunscreen-how-help-protect-your-skin-sun https://www.fda.gov/drugs/understanding-over-counter-medicin...

orangepurple 4y ago

One of the most interesting sunscreen metrics is mentioned completely unceremoniously on the last page of the Final Order Monograph 2020. It is sad that we don't have access to the critical wavelength value calculations described on the last page of Monograph M020. The critical wavelength is identified as the wavelength at which the integral of the spectral absorbance curve reaches 90 percent of the integral over the UV spectrum from 290 to 400 nm. A mean critical wavelength of 370 nm or greater is classified as broad spectrum protection. Sunscreen users could benefit from understanding the UV blocking performance of each sunscreen on the market. Reference: U.S. Food and Drug Administration Final Administrative Order (OTC000006) Over-the-Counter Monograph M020: Sunscreen Drug Products for Over-the-Counter Human Use (Posted September 24, 2021) https://www.fda.gov/drugs/understanding-over-counter-medicines/sunscreen-how-help-protect-your-skin-sun https://www.fda.gov/drugs/understanding-over-counter-medicin...