There are two different types of ultraviolet filters available: chemical and mineral. But how are they different and which one is more eco-friendly?
If you have looked into eco-friendly sunscreens, you will know that most of the commonly used UV filters negatively affect marine life. The common consensus among scientists is that mineral UV filters are better for our environment than chemical ones.
But given how important sun protection is, and sunscreen plays a vital part, you might wonder what the difference between chemical and mineral sunscreens is. So let’s find out…
Difference Between Chemical And Mineral Sunscreen At A Glance
| Chemical Sunscreen | Mineral Sunscreen | |
|---|---|---|
| What’s it made from? | Carbon (organic material) | Mineral (inorganic material) |
| Is it chemical? | Yes | Yes |
| How do they work? | Absorbs UV radiation and turns it into heat | Mostly absorbs UV radiation and scatters/reflects some of it |
| UVA or UVB protection? | Mostly UVB, some UVA and some both | UVA and UVB |
| How do they behave on skin? | Gets absorbed by skin | Forms protective layer on skin (non-nano) Nano particles get absorbed |
| How quickly do they work? | 20 – 30 minutes after application | Immediately after application |
| Health concerns | Yes | No (non-nano); potentially (nano) |
| Environmental impact | Yes | Little (non-nano); yes (nano) |
Difference In Source Material
Let’s start at the beginning. One difference between the two ultraviolet filters is what they are made of. Chemical UV filters are synthetic chemical structures that are made from carbon.
Because carbon is an organic material, chemical filters are also called organic ultraviolet filters. On the other hand, mineral filters are also called inorganic, because they are made from inorganic minerals. (Nieradko-Iwanicka et al., 2022)
In both cases, the source material has to be chemically altered to get the actual ultraviolet filter. So while mineral filters are often seen as natural, they are still made in the lab.
There is a large number of chemical UV filters available, including avobenzone, homosalate, benzophenones, octisalate and octocrylene. But only two mineral ultraviolet filters are approved to be used in cosmetics: zinc oxide and titanium dioxide.
Difference In How They Work
There is a misconception that one difference between chemical and mineral sunscreen is that the former works by absorbing UV radiation and the latter by reflecting it. This isn’t quite true.
Both predominantly protect our skin by absorbing harmful UV radiation. Chemical filters turn the energy into heat, which is released and distributed across the skin. (Gabros et al., 2019)
While inorganic filters do scatter or reflect UV radiation, it’s less than 5%, the rest is absorbed. However, what mineral filters do reflect is visible light, between 30% and 50% of it. (Cole et al., 2015)
That’s why mineral sunscreens can leave your skin appear whitish after application. To counteract this, manufacturers have started to reduce the size of the inorganic UV filters and now so-called nanoparticles are used. (Manaia et al., 2013)
One thing that needs to be said is that both chemical and mineral UV filters work in protecting you from harmful UV radiation, even if they work in slightly different ways.
UVA And UVB Radiation
Although both types of ultraviolet filters work in a similar way, there is a difference in which radiation they absorb.
Most chemical filters only work to protect your skin from UVB radiation and some only work for UVA radiation. Some of the newer organic UV filters are classed as broad spectrum as they absorb both UVA and UVB radiation. (Gabros et al., 2019)
Chemical sunscreens tend to use a mixture of different organic UV filters to achieve broad spectrum protection and increase the SPF factor.
In contrast, both mineral UV filters, zinc oxide and titanium dioxide, are classed as broad spectrum because they protect against both UVA and UVB rays. However, to achieve the best protection, they are used in combination. (Abou-Dachech et al., 2022)
That’s also the reason why some sunscreens, especially ones with higher SPF, use a combination of chemicals and mineral UV filters. The latter is normally in nano form.
Difference In Interaction With Skin
Another difference is how they interact with your skin. Chemical UV filters need to get absorbed by skin, before they can start protecting you. That’s why you need to wait for around 20 to 30 minutes after application before you can go into the sun safely.
On the other hand, mineral ultraviolet filters don’t get absorbed but form a protective layer on your skin. Hence, why they work as soon as you have applied the sun lotion. And it explains the white film you might get with mineral sunscreens.
However, this is only true if the inorganic filters are in non-nano form. This means they are too big to be absorbed by the skin. In nano form they are small enough to be absorbed.
Health Implications
This different interaction with your skin leads to health implication. Because chemical UV filters are absorbed by the skin, their use can cause skin irritation or other skin conditions.
Mineral filters cause less irritation because they aren’t absorbed and are seen as better, especially for sensitive skin. (Ekstein et al., 2023)
But the health implications for chemical and nano-sized mineral UV filters go further. As they are absorbed, they are able to get into our bodies. A study has found chemical UV filters in blood and skin samples of participants. (Matta et al., 2020)
There is growing scientific evidence that long-term exposure to these organic UV filters can have a negative impact on our health. (Lorigo et al., 2024; Wang et al., 2021; Fu et al., 2024)
Generally, scientists are of the opinion that non-nano mineral UV filters are the best option for human health.
Difference In Environmental Impact
As we have seen, there is quite a difference between chemical and mineral sunscreens when it comes to the health impact on humans. And generally speaking, what’s bad for us is very likely also bad for the environment.
If our skin can absorb chemical UV filters, then aquatic life and plants can too. And we know that they are present in our waterways, because studies have been conducted all over the world. (Mozas-Blanco et al., 2023)
And research has shown that organic filters have a bigger impact on our environment than inorganic ones. Several marine species have been studied to establish if exposure to organic UV filters causes harm.
The results show that they can impact on cardiac and locomotor activity of crayfish. (Malinovska et al., 2023) The larvae of zebrafish were found to be negatively affected by exposure to the organic UV filters beznophone-3 and nano titanium dioxide. (Sun et al., 2022)
Studies have also linked commonly used chemical UV filters with coral bleaching. (Moeller et al., 2021) Yet another study has shown that some UV filters are toxic to invertebrates. (Kusk et al., 2010)
I could go on, as there are plenty more studies showing the negative impact chemical sunscreens and nano mineral sunscreens are having on our planet.
While no sunscreen is 100% safe for our environment, scientists have come to the conclusion that non-nano mineral UV filters are the most eco-friendly option. (Schneider et al., 2018)
So this is the difference between mineral and chemical sunscreens. Armed with this knowledge, you can make the best decision for yourself and the planet.
More Information:
If you want to know more, head to our article about all you need to know about eco-friendly sunscreen.
