Same SPF number, different coverage: Doctor breaks down different types of sunscreen

MARQUETTE, Mich. (WLUC) - No two sunscreens are the same, even if they claim the same SPF number.

That’s what Dr. Greg Sulik of Medical Acne and Skincare tells TV6′s Tia Trudgeon.

Basic SPF calculation works like this: if you get a sunburn after one minute in the sun, SPF 15, in theory, will protect you 15 times longer.

Dr. Sulik adds that SPF refers to sunscreen’s ability to protect from burning, AKA, UVB rays. Unless it states “broad spectrum” on the bottle, the sunscreen won’t protect you from UVA rays, which cause aging.

And while windows may block UVB light from passing through, they still let UVA light in.

Two different brands of SPF 30 sunscreen, for example, may not provide the same coverage.

There are two basic types of sunscreen: the kind that absorbs light, and the kind that reflects light.

Light-absorbing sunscreen still allows light to penetrate through the skin, and can cause reactions on sensitive skin and aging.

Light-reflecting sunscreen will provide greater coverage for fairer skin. This type of sunscreen uses titanium and/or zinc to block UV rays.

Dr. Sulik demonstrates how light passes through these types of sunscreens.

Off camera, Dr. Sulik tells Trudgeon that most people don’t wear sunscreen properly and it must be reapplied every two hours, or in accordance with the directions on the bottle.

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