Below, we’ll discuss everything you need to know between both sunscreens to help you make a better decision.
The Main Difference Between Chemical and Physical Sunscreen
Before we begin, it’s important to note that both chemical and physical sunscreens do include chemical substances. It’s a very common misconception that the main difference between the two is the chemical content, but that’s actually not the case.
Instead, the main difference between the two sunscreen types is how they work:
Physical sunscreen works by physically blocking’ or reflecting 5 to 10% of the UV light so it won’t penetrate your skin. This is why physical sunscreen is also often called as sunblock. Chemical sunscreen absorbs into the skin and then works chemically’ from inside your body, absorbing UV light, transforming the rays into heat energy, and then releasing them from your body.
Their different methods’ of protecting your screen are caused by different UV-filtering chemical substances contained. So, the easiest way to differentiate between chemical and physical sunscreens is to check their chemical ingredients:
Physical sunscreen typically contains zinc oxide and/or titanium dioxide. Chemical sunscreen contains more varied ingredients, the common ones are avobenzone, octisalate, octinoxate, octocrylene, oxybenzone, helioplex, homosalate, Mexoryl SX/XL, 4-MBC, Uvinul T-150, and Uvinul A Plus, and Tinosorb S/M among other substances.
Differences in UV Protection
Both chemical and physical sunscreens are able to reach SPF 100+ protection level, the highest SPF offered in the market, and the current recommended level.
However, there are some differences mainly in the photostability aspect and how broad the UV radiation spectrum they can protect against.
Ultraviolet rays can be divided into two types based on the electromagnetic spectrum:
-UVA (associated with aging)
-UVB (associated with burning)
Physical sunscreens containing titanium dioxide, generally are only able to protect against UVB and only partially against UVA. Zinc oxide, on the other hand, can protect against both UVA and UVB.
Chemical sunscreens, on the other hand, generally offer wider protection on both UVA and UVB.
Photostability refers to how well the UV filter can withstand sunlight and heat exposure before it degrades (and so won’t be effective and you’ll need to reapply them). In this aspect, physical sunscreens generally offer better photostability compared to chemical sunscreens.
However, newer chemical sunscreens (i.e. those containing uvinul A or tinosorbs S/M) offer really good photostability. Some chemical sunscreen ingredients like avobenzone offer really good UVA protection, but relatively low photostability.
Side Effects and Irritation Risks: If You Have Acne-Prone or Sensitive Skin
If you have sensitive skin, you have to be more careful in choosing chemical-type sunscreens.
Some chemical sunscreens tend to be more irritating for some people. Avobenzone, oxybenzone, enzacamene, octocrylene, and PABA are some ingredients that can potentially cause irritation or allergic reactions.
They are typically not life-threatening but can be very uncomfortable. In general, physical sunscreen is the better choice if you suspect yourself of sensitive skin, or if you have acne-prone skin.
Also, look for sunscreens that contain niacinamide (a subtype of vitamin B3). Niacinamide can help reduce the appearance of skin discolorations and blemishes.
Always be aware of your skin’s reaction, and contact your local dermatologist or pharmacist if you suspect prolonged allergic reactions. You can also ask for different samples if you aren’t sure about your skin’s sensitivity and which sunscreen is right for you.
Color and Texture
As mentioned above, physical sunscreens are generally more photo-stable so you don’t have to reapply them all the time. However, physical sunscreens tend to feel heavier’ and will often leave a white cast on your skin.
On the other hand, chemical sunscreens typically produce significantly less white casts and have a lighter texture, so they are more comfortable to wear daily. Some chemical sunscreen products are also formulated as makeup foundation.
However, due to the lower photostability, you might need to reapply the chemical sunscreen every few hours to maximize sun protection.
Chemical Sunscreen VS Physical Sunscreen: Pros and Cons
Based on the several different factors we have discussed above, here are the pros and cons of the two types of sunscreen:
Chemical Sunscreen: Pros and Cons
Pros:
Lighter in texture, and generally won’t produce white cast, more comfortable to wear daily works better under makeup. Some are even formulated as makeup foundation offer wider protection against both UVA and UVB electromagnetic spectrum. Some chemical sunscreens are water-resistant, so a better choice for swimming.
Cons:
It needs to reapply every three or four hours. Greater risks for allergic reactions and irritability. Some chemical ingredients might damage the skin and living tissue in long-term usage.
Physical Sunscreen: Pros and Cons
Pros:
Works immediately after application since it blocks’ the UV rays physically. It is a better choice for sensitive skin in general, relatively safer for long-term usage with less chemical content better photostability, don’t need to reapply every few hours
Cons:
Oily, heavier texture and often leave a white cast. In most cases, worse protection against UVA
How To Choose Your Sunscreen
Based on the pros and cons we have discussed above, here are some considerations when choosing the right sunscreen according to your skin type and needs:
Chemical sunscreen tends to be the better option if:
You are very active or sweat a lot. Need a water-resistant sunscreen (i.e. if you are swimming). Want a sunscreen that is more comfortable to wear with the lighter, refreshing texture
Physical sunscreen is a better option if:
Water-resistance is not an issue and you don’t sweat a lot. Don’t want to reapply the sunscreen every three or four hours. Don’t mind the heavier texture and white cast. Have a sensitive or acne-prone skin
Other factors you might want to consider:
How broad the spectrum protection is (protection from both UVA and UVB rays). In most cases, fragrance-free is better, but some might prefer scented sunscreen won’t clog your pores (non-comedogenic). Oil and paraben-free SPF of at least 30, but SPF 100+ is recommended nowadays.
Something to say…
It’s important to understand that both physical and chemical sunscreens do contain chemical ingredients, so it shouldn’t be your main concern when choosing between the two. However, there are some key differences—as we have discussed above— that should be considered.
