Is chemical sunscreen bad for you?

Why do people say chemical sunscreens are bad?

One concern is absorption. FDA studies detected common sunscreen ingredients in the blood of people applying large quantities of sunscreen. Absorption does not equal a health risk, and those findings are not a reason to stop using sunscreen. Health Canada agrees with that position.1

Absorption also depends on the formula, not just the filter's name. The way a sunscreen is formulated and its other ingredients can affect how much of a chemical filter passes through skin. Treating every chemical sunscreen as identical misses that distinction.2

Another concern is coral reefs. Some places restrict particular sunscreen filters because of environmental concerns, so check local rules before travelling. The effect of sunscreen ingredients on reefs remains uncertain. The FDA has no official definition of "reef safe", so the front of the bottle is doing more talking than the rulebook.34

Is sunscreen bad for your skin?

Sunscreen protects skin from damaging ultraviolet rays, but a particular formula can cause irritation or allergy. Side effects are rare. A reaction can come from a UV filter, fragrance or preservative, so a rash does not automatically mean chemical filters are the problem. Allergic contact dermatitis, an allergic skin rash, can appear where sunscreen was applied and sometimes spread elsewhere.15

Before trying a new sunscreen, especially on sensitive skin, test a small area of the inner forearm and check it after 48 hours. If a sunscreen causes itching or a rash, stop using that product and try another formula. Ask a healthcare professional about a concerning reaction or repeated problems. Passing a small area test does not rule out irritation.15

A dermatologist can use patch testing to identify an allergen. If reactions happen where sunscreen and sunlight meet, photopatch testing, which includes light exposure, can help investigate. Avoid the ingredient you are allergic to rather than abandoning sun protection.5

Should you switch to mineral sunscreen?

Mineral sunscreen containing zinc oxide or titanium dioxide is a reasonable choice for sensitive skin or sunscreen allergy. Chemical, mineral and hybrid sunscreens can all protect effectively when they offer broad spectrum protection, SPF 30 or higher and water resistance. Both chemical and mineral filters protect primarily by absorbing UV rays; mineral filters also reflect some rays.356

Read the active ingredients to identify the sunscreen type, and check the rest of the ingredient list for anything you already know you react to.14

How should you use sunscreen?

1. 1Choose broad spectrum SPF 30 or higher with water resistance. Broad spectrum means protection against both UVA and UVB rays.
2. 2Apply generously to dry, exposed skin at least 15 minutes before going outdoors. Include your ears, neck, hands and exposed scalp. Follow the amount on the label; Health Canada's adult guide is about seven teaspoons for all exposed areas, including one for the face and neck.
3. 3Reapply at least every two hours outdoors and after swimming, sweating or towelling off. Follow the bottle's water resistance directions.
4. 4Use shade and protective clothing as well. No sunscreen blocks all UV rays, and sunscreen is not permission to stay outside longer.

Check the expiry date and keep sunscreen out of direct sunlight and hot cars. Expired sunscreen and sunscreen exposed to extreme heat can be less effective.1