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How Sunscreens Work: Mineral vs. Chemical

by kelly / July, 8 2015 01:30

Hope you are all enjoying the summer and getting in some fun at the beach and in the sun.

Of course I also hope you are wearing sunscreen. I'm sure you are because you all are frequent readers of our suncare smarts education series Cool!

Lately a number of people have asked me how sunscreens work and specifically the difference between mineral and chemical sunscreens. I'm here to answer this question for you all in our latest suncare smart series...

Mineral vs. Chemical - What's the Difference

Now a while back we covered what is mineral sunscreen but here's a quick refresher course. What differentiates a mineral vs. chemical sunscreen is the UV filter(s) used in the sunscreen. UV filters are the active ingredients in a sunscreen that protect you from the sun. In the United States all sunscreen companies are required by the US Food & Drug Administration (FDA) to list on their packaging the active ingredients used.

A note of caution - don't simply rely on a sunblock saying it's "mineral based". Some sunscreens will say this on the front but a check of the ingredients on the back shows both mineral and chemical UV blockers. Be sure to check the ingredients.

Sunscreen active ingredients (mineral vs. chemical) are listed in the table below. Note that these are the UV filters approved for use in the US. Other countries have different and/or more ingredients approved as chemical UV filters.

Mineral SunscreenChemical Sunscreen
Titanium Dioxide
Zinc Oxide
Aminobenzoic acid
Ecamsule (Mexoryl SX)
Ensulizole (Phenylbenzimiazole Sulfonic Acid)
Meradimate (Menthyl Anthranilate)
Octinoxate (Octyl Methoxycinnamate)
Octisalate ( Octyl Salicylate)
Padimate O
Trolamine Salicylate

Most sunscreens found in the drug store will be chemical ones. As I mentioned, you'll also find some hybrids of the two that use both mineral and chemical UV filters. There may be some mineral only sunblocks too (like ours!) but those are less common. So always check the ingredient label if you are concerned about the type of sunscreen you are buying.

Additionally, if you are wondering about the spectrum of UV protection coverage that each UV filter provides - well we got information on it here.

How They Work

Block Island Organics Infographic - How Sunscreen / Sunblock Works: Mineral vs. Chemical

Mineral sunscreens are also known as physical sunscreens or physical blockers or mineral sunblock or sunblock. The reason is because mineral sunblocks act as a physical barrier to UV rays. Mineral sunscreens sit on top of the skin and reflect the UV rays back away from the body. Thus the UV rays cannot penetrate the skin. Despite this you'll still see mineral sunblocks labeled as "sunscreen" and not "sunblock". This is due to FDA labeling regulations.

Chemical sunscreens work differently. The chemical UV filters actually absorb into the skin. Once absorbed, when UV rays hit them the chemical sunscreens release the UV rays' energy as heat. Converting UV rays into heat is part of what causes chemical sunscreens break down after being used for a few hours while physical sunscreens tend to last longer. Regardless, it's still advisable to reapply every two hours no matter which type of sunscreen you use even though a mineral/physical sunscreen should last a little longer.

Additionally, that's why it's recommended to apply chemical sunscreens around 20 minutes before heading out into the sun. Chemical sunscreens need to absorb into the skin before they become effective while mineral sunscreens tend to work immediately because they sit on top of the skin. All sunscreen labels will say to apply 20 minutes before sun exposure but mineral sunscreens will work quicker.


So you know what we are going to recommend as a non-toxic mineral suncare company - mineral all the way! Even with our own bias, other organizations agree that mineral sunscreens are generally considered better for people with sensitive skin. For example the Environmental Working Group (EWG) is a big proponent of mineral vs. chemical.

Plus zinc blocks the full UV spectrum but to get full broad spectrum coverage using other UV filters you generally have to combine them. But to be fair we'll just say that no matter which kind you choose, year-round sun protection is important to prevent skin damage and premature skin aging.

Furthermore, both the Skin Cancer Foundation and American Melanoma Foundation recommend using a broad spectrum (UVA/UVB) sunscreen with an SPF of 15 or higher every day. That's what we do - SPF 30, broad spectrum, mineral sunscreen.

There you have it. Here's more information on suncare and sunscreen / sunblock - hope it helps you stay protected all year round. Remember it's about playing smart and safe in the sun.

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