Two names, two families of filters
Sunscreens use UV filters, and these are generally sorted into two groups. Mineral sunscreens, also called physical or inorganic, use zinc oxide, titanium dioxide or both. Chemical sunscreens, also called organic, use carbon-based compounds with names you may see on ingredient lists, often long and technical.
The labels are a little misleading, because every sunscreen ingredient is a chemical in the everyday sense. The terms simply describe two different kinds of filters, and many products combine them.
How they work
Chemical filters absorb UV radiation and convert it into a small amount of heat that leaves the skin. Mineral filters were long described as sitting on top of skin and reflecting UV like tiny mirrors. A more accurate picture, as it is generally understood, is that they both absorb and scatter UV. The difference in mechanism is less clear-cut than older descriptions suggest, and it matters less for everyday use than how a product feels and how consistently you wear it.
Both groups can offer broad spectrum protection when a product is formulated and tested for it. Zinc oxide on its own is generally considered to cover a wide range of UVA and UVB. Chemical formulas often combine several filters to cover the range. The ideas behind that label are covered in the article on broad spectrum protection.
How they tend to feel
These are generalizations, and modern formulas vary a great deal.
| Aspect | Mineral | Chemical |
|---|---|---|
| Typical finish | Can look opaque or leave a white or grayish cast, especially on deeper skin tones | Often clear and light, blends in easily |
| Texture | Can feel thicker or drier | Often thin and fluid |
| Time to take effect | Generally considered to work as soon as applied | Often recommended to apply 15 to 20 minutes before going out, per many labels |
| Under makeup | Can be chalky or pill with some layers | Usually layers smoothly, though some feel slick |
| Sensitive skin | Often well tolerated | Some people react to particular filters |
Tinted mineral formulas can reduce the cast, and newer particle sizes can make mineral products look more transparent. Whether that suits you is a personal matter.
Skin type and sensitivity
Many people with reactive skin start with mineral products because they tend to have fewer ingredients that irritate, and zinc oxide is also a common ingredient in gentle skin products. That said, a formula can irritate for reasons that have nothing to do with the filter, such as fragrance or other additives. Anyone who is sensitive can look at the points in the article on sensitive skin and use patch testing before trying a new product. If you break out easily, the cues in the article on acne prone sunscreen are useful for either type.
Chemical filters can sting if they get into the eyes, particularly when you sweat. Mineral formulas may also sting for some people, so there is no absolute rule.
Water, sweat and reapplication
Both types can be labeled water resistant for a set time, often 40 or 80 minutes. Neither is waterproof, and neither lasts all day without reapplying. The details are in the article on sunscreen reapplication. Mineral powders and sticks can make reapplying easier, but whether brush-on powders give enough coverage on their own is uncertain, so they are best seen as a top-up.
Safety and environmental questions
You may see debate online about filters. Regulators in different countries review ingredients and approve different lists, so a filter allowed in one place may not be available in another. Some regions have also restricted certain filters in areas where reef protection is a concern. Research continues, and it is hard to summarize firmly, so if an ingredient worries you, check with a pharmacist or doctor and look at your local regulator’s guidance. Skipping sunscreen is not generally recommended as a response.
Which should you choose?
There is no single best option. A reasonable way to decide:
- Start with your skin: sensitive and reactive skin often begins with mineral; oily or deeper-toned skin often prefers a lighter finish.
- Consider your day: swimming, sports and makeup all affect how a formula performs.
- Pick the one you will use generously and regularly. A product that stays in the cabinet protects nothing, and applying enough matters, as explained in the article on sunscreen amount.
Whatever you choose, look for broad spectrum protection and an SPF that matches your plans. If you have concerns about a reaction, a rash or a skin change, a qualified health professional can advise. This article is general information, not medical advice.