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What the experts say

Leslie BaumannMD · dermatologist, cosmetic dermatology and appearance medicine

Prefer mineral

What it rests onThe benzophenones were named Contact Allergen of the Year in 2014 by the American Contact Dermatitis Society; estrogenic activity in cell and animal work with detection in breast milk and urine; pending FDA data requests. She concedes in the same article that chemical filters give the best broad-spectrum protection and that mineral filters miss part of the UVA range.

Source: skintypesolutions.com ↗

Michelle WongPhD · chemist and science communicator

Use the one you will apply generously and often

What it rests onRisk equals hazard multiplied by exposure, applied filter by filter, plus the FDA absorption studies read as absorption rather than as harm.

Source: labmuffin.com ↗

Overview

Baumann is prescribing for patients who present with rashes and reactions, which is a population enriched for contact and photoallergy, and she scopes her strongest avoidance advice to pregnancy, breastfeeding and preconception. Wong is addressing the general adult population and is arguing about the cost of a swap made on an exposure inference nobody calculated.

Where they agree

Complete, on everything that matters most. Both hold that daily sunscreen is established and that adherence beats filter chemistry: bau-spf-best-is-used and won-best-sunscreen are near-identical sentences. Baumann also states in her own words that absorption into the bloodstream is not a finding of harm, and that a sunscreen you have doubts about beats no sunscreen at all.

What would settle it

For Baumann's contact allergy case, updated allergen frequency data would move it in either direction. For the endocrine half, human outcome data at real-world exposures rather than cell and animal work. Neither side is waiting on the same study, which is itself the finding: they are arguing about how to act while an open question stays open, not about what the evidence currently says.

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