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What’s the difference between chemical and mineral sunscreens and which is best for your skin?


Got acne, rosacea, eczema or just sensitive skin? Ever wondered why so many people with these skin types turning to mineral sun screens?

You hear a lot of talk about mineral sun blocks these days. But what’s the actual difference between a mineral sun block and a normal chemical sun filter that you find in most sun creams on the high street.

And why are so many people with sensitive skin, acne or rosacea opting for mineral sun creams?

Chemical sun filters explained

Chemical sunscreens contain organic (carbon-based) compounds, such as oxybenzone, octinoxate, octisalate and avobenzone, which create a chemical reaction and work by changing UV rays into heat, then releasing that heat from the skin.

They are often referred to as chemical or organic absorbers, which can be confusing as when we hear the word ‘organic’ we tend to think ‘non-chemical’ or natural.

Chemical sunscreens work by absorbing the sun’s rays which is why they are often referred to as sun filters.

Chemical sunscreens can offer more coverage as they go onto the skin more smoothly. However, they take between 20-30 minutes after application to become effective.

More importantly for people with sensitive skin, chemical SPF ingredients produce free radicals when exposed to direct sunlight. Essentially their chemical ‘constitution’ can alter slightly when exposed to UV light and heat. This slight change in composition can cause skin irritation in people with sensitive or problem skin, in particular rosacea and acne.


Pros of chemical sunscreens:

  1. They tend to be thinner and smoother and so spread more easily on the skin, making it more wearable for daily use
  2. Their formula is easier to add additional treatment ingredients which offer other skin benefits
  3. They can be made very cheaply.

Cons of chemical sunscreens:

  1. They require about 20-30 minutes after application before it begins to work
  2. They increase the chance of irritation and stinging (especially for those who have sensitive skin or dry skin with a damaged moisture barrier such as skin prone to eczema) due to the multiple ingredients combined in order to achieve broad spectrum UVA and UVB protection
  3. The higher the SPF (such as formulas of SPF 50 or greater), the higher the risk of irritation for sensitive skin types
  4. The sun protection that chemical SPF’s offer gets used up more quickly when in direct UV light, so reapplication must be more frequent
  5. Increased chance of redness for rosacea-prone skin types because it changes UV rays into heat which can exacerbate flushing
  6. They can cause stinging if they drip into the eyes when mixed with sweat.


Mineral sun blocks explained

Mineral sun blocks are described as ‘physical’ sun blocks, in that they sit on the top of the skin and literally block or deflect the sun rays away from the skin.

Zinc oxide and titanium dioxide are physical mineral sun blockers. Mineral sun blocks work immediately after application.

Zinc oxide is potentially more effective than titanium dioxide as it provides protection against the entire spectrum of UVA and UVB rays.


Pros of mineral sunscreens

  1. They are much better for sensitive skin as they do not change in their constitution when exposed to heat.
  2. They do not ‘heat up’ when exposed to sun, in fact they deflect heat from the skin so are beneficial for skin prone to rosacea.
  3. Zinc oxide is also an anti-inflammatory so can help control inflammation in rosacea-prone skin and reduce break outs of acne. Kalme Day Defence SPF25 contains pure micronized zinc oxide
  4. They offer protection against both UVA and UVB rays and are naturally broad spectrum
  5. They work immediately.
  6. They last longer when in direct UV light

Cons of physical sunscreens:

  1. They can rub off if mixed with sweat or water.
  2. They can leave a white-ish tint on the skin, although more modern micronized versions of mineral ingredients make this less of problem. The only downside is that these modern mineral ingredients are quite expensive as raw materials.
  3. They can have a slightly chalky feeling on the skin.
  4. The mineral SPF creams are usually thicker, which requires more effort to rub in over larger areas.


So now you know!

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