Chemical vs. Physical Sunscreens: The Science Behind Their Effects
Are chemical or physical sunscreens better?
I touched on this in my latest Instagram Reel, but a few people asked me to talk more about it, as they were surprised by what I said in the video.
What are we going to cover in this blog post:
- What Are Chemical and Physical Sunscreens?
- Differences Between Chemical and Physical Sunscreens
- Myths About Chemical and Physical Sunscreen Differences
- Bottom Line
WHAT ARE CHEMICAL AND PHYSICAL SUNSCREENS?
The active ingredients in sunscreens are often divided into two categories:
- Physical sunscreen ingredients (more correctly known as inorganic sunscreen ingredients) are zinc oxide and titanium dioxide.
- Chemical sunscreen ingredients (more correctly known as organic sunscreen ingredients) are everything else.
You can have sunscreens containing only organic filters, only inorganic filters, or a combination of both. Not sure why one would have a combination of both, as typically you have camp "I love inorganic aka physical" or "I love organic aka chemical ones".
The reason organic (carbon-based) and inorganic (not carbon-based) is a better classification than chemical/physical is that there’s overlap between how they work. Both types work by absorbing UV and turning it into heat. Inorganic sunscreens also scatter and reflect about 5-10% of the incoming UV, as do some particulate organic sunscreens like Tinosorb M, so really they should be classified as both chemical and physical. I know - for years now, big beauty companies tried to make you believe one is better than the other and here we are now. As the sunscreen market is worth 14.9bn in 2024. So no, a physical isn't a shield you place on your face and every sun ray bounces off you. This is one of the biggest myths that one big company has ever created to boost their sales and generate fear among customers.
DIFFERENCES BETWEEN CHEMICAL AND PHYSICAL SUNSCREENS
The big differences between them that you should consider are:
PROTECTION LEVEL
A high SPF is pretty common with both types of sunscreen, although I would like to caveat this as mineral sunscreens are typically in your SPF 30, while there are more chemical or a combination of the two that actually are in the SPF 50 range. And the simple explanation is that you need approx 25% of zinc oxide to achieve an SPF 50. You can imagine what that might look like on your face and what it feels like. But broad-spectrum protection (that includes protection against longer wavelengths of UVA) is where there’s a difference. And something that is not very common.
Organic (what most people call chemical or even synthetic) sunscreens give higher, photostable protection from UVA if you use newer filters. And a fun fact; a lot of the newer filters are not available in countries like the USA. They still live in the dark age using very outdated sunscreens such as avobenzone. There are 27 UV-Filters available for chemists in Europe and a meager 16 UV Filters in the US that have been approved by the FDA. Avobenzone is the most common filter as it gives really high UVA protection, but it breaks down in UV. So if you see this ingredient, stay clearly away from it - unless you are a very diligent person in reapplying the sunscreen every other hour. And let's be true to ourselves - who enjoys reapplying their sunscreen? It is shocking to see how many brands still formulate in the 2024 with this outdated UV filter.
Ultraviolet A Protection Factor, also known as UVAPF, is a measurement of UVA protection. You can’t really tell what the UVAPF of a sunscreen is without actually testing it. Very roughly speaking, for sunscreens with a tested, publicly available UVAPF value, inorganic sunscreens get around UVAPF 20 max, if correctly formulated. While all the highest UVAPF sunscreens are organic and can get around UVAPF 40% – if you’ve seen higher, let me know! Our Everyday Sun Cream 50+ has reached a UVAPF of 40%.
WHITE CAST
Organic sunscreens tend to leave less white cast while inorganic sunscreens tend to be very white (especially if they have titanium dioxide).
I am quite fair-skinned, and inorganic sunscreens still commonly make me look mime-like if I apply 2 mg per square centimeter to get full protection, which translates to about approx. 1/2 of a teaspoon for me. This makes it hard to apply a generous amount, and since SPF scales with how much sunscreen you apply, this is an issue. And with zinc oxide and titanium dioxide, there is always a white cast. I appreciate many brands are saying "You need to rub it in" but actually, by doing so, you rub off the sun protection again.
TEXTURE
Sunscreens often have really thick, greasy textures, and depending on your skin, one type might suit you better. I personally prefer organic sunscreens, since I’ve found quite a few that feel like moisturizers. And you want to enjoy the feel of it otherwise you won't wear it. If you feel it is making you a little shiny, then wait till it has settled and apply a light BB cream on top or a powder to remove the shine.
SENSITIVE SKIN
If you’re in the US, avobenzone is in almost all broad-spectrum organic sunscreens. Avobenzone is a common irritant and allergen, so it tends to be unsuitable for sensitive skin, and you’re left with inorganic sunscreens only as an option. But like I said, avobenzone is so outdated, which is shocking that this is still found in modern and high-quality products. Brands that use it say "they are pioneering and innovative". Well, no.
If you’re elsewhere in the world, the newer UVA1 filters aren’t irritating or allergenic. But you still need to be picky and look for high-quality products, as a lot of brands cut corners to keep a low price point. In Germany, most people don't want to spend more than 15 Euros or even less on sunscreen. Considering a high-quality sunscreen can protect your skin from premature aging, hyperpigmentation, and skin cancer, my German fellow people are way too stingy. But hey, clearly have the money to invest in expensive laser treatments.
A few other organic sunscreens also tend to cause allergic and irritant reactions: octocrylene, oxybenzone, avobenzone, PABA, Padimate O, and enzacamene.
And none of these outdated and low-quality filters are found in our high-quality sunscreen.
MYTHS ABOUT CHEMICAL AND PHYSICAL SUNSCREEN DIFFERENCES
There are a whole bunch of myths surrounding the topic of chemical and physical sunscreen. And here we have created a snapshot of some of those myths. Some of the most common myths are:
- YOU NEED TO APPLY CHEMICAL SUNSCREENS FIRST AND PHYSICAL SUNSCREENS LAST
- YOU NEED TO WAIT FOR CHEMICAL SUNSCREENS TO WORK BUT PHYSICAL SUNSCREENS WORK IMMEDIATELY
Both of these myths are based on the misconception that chemical sunscreens need to absorb into your skin and bind before they work – but both types of sunscreen work straight out of the bottle.
All sunscreens just need to form a continuous film on your skin, and they’ll work, so you can apply them exactly the same way. And that is the issue when brands offering physical/mineral sunscreen say "you need to work it in / rub it in and the white cast goes away" – as this breaks and disturbs the continuous film on your skin.
PHYSICAL SUNSCREENS ALSO BLOCK BLUE LIGHT
Blue light filtering protection isn't something that’s yet widely available, but there are definitely studies to suggest that the best physical sunscreens do indeed block this. Some research suggests physical sunscreens (especially zinc oxide) protect from blue light as well as UVA rays, but this research is still fairly new and needs a little more testing to confirm.
BOTTOM LINE
The bottom line is, whether you prefer chemical (organic) or physical (inorganic) sunscreen, it's really about what works for your skin and how comfortable you are with the texture and the amount of protection it provides. Choose a sunscreen that suits your needs – whether you’re looking for a high-SPF, more UVA protection, or a formula that works well with your skin type.
And as always, protect your skin from the sun! The sun is aging your skin prematurely and increases your risk of skin cancer, so apply sunscreen whenever you're going outdoors.
If you want to learn more about sunscreens, there are a whole bunch more posts I have on them – here are a few:
Does sunscreen deplete me from Vitamin D
Why you should protect your skin from UVA
Science between Chemical (organic) and Physical (inorganic) sunscreens
Leave a comment