Physical Sunscreen vs. Chemical Sunscreen (Sunblock)
Originally Published on June 26, 2018. Updated on July 29, 2021
By now you’ve heard that wearing sunscreen (even on cloudy days during the winter months) is the most effective way to protect your skin from sun damage, early onset aging, and even skin cancer. You probably also know that you should be using a broad-spectrum formulation (meaning it protects the skin from both UVA and UVB rays) with a high Sun Protection Factor (SPF).
Aside from remaining in the shade or wearing protective clothing, sunscreen is the best way to protect the skin from being overexposed to dangerous UV rays, which can lead to sunburns, skin damage, early onset aging (photo aging) and skin cancer.
Choosing a sunscreen, however, can be difficult since there are so many different types to choose from. Today’s market features hundreds of different sunscreen options; there are sunscreens with varying Protection Factor (SPF) level, products with added tint to hid blemishes, sunscreen formulations with added anti-aging ingredients, and specific sunscreens made for the face or body. Additionally, sunscreens can come in lotion, stick, powder, or even spray-on application varieties. While options are good, sometimes having so many different options can be overwhelming!
At a minimum, its crucial to choose a broad-spectrum sunscreen with a high SPF. Beyond that critical distinction, all sunscreens can be categorized as either a chemical sunscreen or a physical sunscreen. There are some key differences between how each type works. Here are the benefits (and drawbacks) of chemical and physical sunscreens.
Chemical vs. Physical Sunscreen: The Key Difference
The main difference between chemical sunscreen and physical sunscreen is how they work:
- Physical sunscreen (often called sun block) sits on top of the skin and works by deflecting away UV rays. When applied to the skin, you can think of physical sunscreen as a mirror shield that limits the amount of UV rays that penetrate the skin by bouncing them away. Common active ingredients of physical sunscreen include minerals such as titanium dioxide and zinc oxide.
- Chemical sunscreen is different as it fully absorbs into the skin. Once absorbed, chemical sunscreen works by converting UV rays that penetrate the skin into heat which is dissipated from the body. Common active ingredients of chemical sunscreens include avobenzone, homosalate, octocrylene, octisalate, octinoxate or oxybenzone.
This difference in methodology creates some key benefits and drawbacks
What Is Physical Sunscreen?
Physical sunblock is often referred to as natural or mineral sunscreen. It sits on top of the skin versus getting rubbed in, so it’s less likely to clog pores. Physical sunscreen remains visible, but does come in a variety of tones, much like your foundation.
Sunblock is photostable, meaning it won’t degrade in the presence of light. It also blocks a wider range of UV rays than some sunscreens. The downside is this thick, mineral paste is visible and may feel heavy on the skin. Sunblock can be difficult to apply and even more difficult to remove. (Hint: Use makeup remover!)
Benefits of physical sunscreen:
- Blocks both UVA and UVB rays (all physical sunscreens are broad spectrum)
- Works as soon as it’s applied to the skin
- Unlikely to irritate the skin, great for sensitive skin types
- Unlikely to clog skin pores as it does not deeply penetrate the skin
- Can limit rosacea and redness as it deflects heat from the skin
- Long shelf life
- Natural minerals are less irritating for those with sensitive skin
- More moisturizing than sunscreen
- Lasts longer than sunscreen when in direct sunlight
- Is effective as soon as it’s applied
- Has a longer shelf life compared to chemical sunscreens
Cons of physical sunscreen:
- Can be rubbed off more easily than chemical sunscreen, especially when it comes in contact with water or sweat (requiring reapplication)
- Often leaves white streaks on the skin that require more effort to fully rub in
- Pores can appear as white spots when sweating
- Not ideal for use under makeup
- May be less protective if not properly applied to all areas of the skin
- Has a thick, often visible appearance
- Can be difficult to evenly blend into skin, especially for full body coverage
- May leave you vulnerable if applied unevenly
- Is more likely to rub off onto your clothes
What is Chemical Sunscreen?
Chemical sunscreen absorbs into the skin to create a chemical reaction when exposed to UV light. This converts UV rays into heat, which is released from the body.
Chemical sunscreen is thinner making it typically easier to apply compared to physical sunscreen, especially if it comes in a spray version. Also, less chemical sunscreen is needed to yield full coverage as there is no risk of unfilled gaps where light can penetrate the skin.
Chemical sunscreens are also a great choice for active occasions as they tend to last longer in the water or when sweating. Unlike physical sunscreen which works instantly, chemical sunscreens need to be applied 30 minutes before exposing the skin to the sun in order to penetrate the skin and provide full protection.
Benefits of chemical sunscreens:
- A thinner formulation makes application easier
- Does not cause significant streaking or white spots
- Smaller amounts are needed to cover large areas of the skin (spreads easily)
- Often found contain other skin care ingredients like peptides and growth factors which can provide added benefits
- Is more resistant to sweat or water compared to a physical sunscreen
- Sunscreen is invisible once applied
- Sunscreen feels lighter or unnoticeable on the skin
- Is more likely to be sweat or water resistant
Cons of chemical sunscreens:
- They only start to be effective 20 minutes after application to the skin
- More likely to irritate the skin (with higher SPF formulations often being more irritating)
- Protection levels begin to drop when in direct UV light (requiring more frequent reapplication)
- Increases the change of redness in rosacea-prone skin types
- Can clog the pores, and thus exacerbate acne
- Often can drip into the eyes causing irritation/stinging
- Some states, including Hawaii, are beginning to ban chemical sunscreen use as they are not “reef safe” and can damage the oceanic ecosystem.
- Higher SPFs may irritate skin more
- In direct light, protection gets ‘used up’ so frequent reapplying is necessary
Best of Both Worlds: Chemical + Physical Sunscreen
It’s possible to combine both chemical and physical sunscreen, if your skin tolerates it. Some chemical sunscreens are irritating to those with sensitive skin, and they do leave you more prone to breakouts. As for physical sunscreen, zinc oxide is gentler on the skin than titanium oxide.
If sensitive skin is not an issue, you’ll reap the benefits of both forms of sunscreen and get the most wide-ranging protection by applying a chemical formula followed by a physical sunblock.
What to Look for In a Sunscreen
No matter what type of sunscreen you chose, chemical or physical, look for the following on the label.
- Broad-spectrum protection from both UVA and UVB rays
- Non-comedogenic formulas that won’t clog pores
- Oil free formulas for acne prone skin
- Paraben-free formulas for reduced risk of skin cancer
- Fragrance free formulas for sensitive skin
- An SPF of 30 or higher for best protection
Chemical sunscreens often have added beneficial ingredients such as peptides, enzymes or Vitamin C.
The Best Sunscreen for Your Skin Type
The best sunscreen or sunblock for you depends on your skin type and skin sensitivity. Even on cloudy days, your skin is at risk from sun damage. Choose a sunscreen that’s compatible with your skin type, and you’ll be more likely to wear it daily.
Acne Prone Skin
Sunscreen can lead to breakouts either because it physically clogs pores, or because the chemicals in it react poorly with your skin. Physical sunblocks are less likely to do either. If you prefer chemical sunscreen, choose one that’s labeled as non-comedogenic.
Those with darker skin should still wear sunscreen to reduce the risk of skin cancer. It can be difficult to find a physical sunblock that’s formulated for darker skin and won’t stand out as white or pasty. Chemical sunscreens blend better in this regard.
Sensitive skin may fare better with the natural minerals of a physical sunblock, which are also moisturizing. If you’d rather use a chemical sunscreen, choose one that’s free from oxybenzone, which has been linked to allergic reactions. In addition, avoid unnecessary ingredients such as fragrance or preservatives.
Which Type of Sunscreen Is Best?
In the end, the best type of sunscreen for you could depend on the specific situation your skin will be put under. If you plan on performing physical activity outdoors (like hiking or jogging on the beach) you may want to opt for a chemical sunscreen as it’s more resistant to sweat. However, a physical sunscreen may be better suited for casual day-to-day activity. Bottom line find a sunscreen you don’t mind the look and feel of, therefore you will be more apt to using it.
dear Dr. Lankerani,
thank you for the clear, concise differentiation of physical versus chemical sunscreens — a much needed product and
and congratulations on your cum laude graduation achievement — not everyone can achieve that.
our daughter is cum laude in economics –U.C. Berkeley.
Another advantage of physical sunscreens is that they are free from objectionable, chemical odors. If you don’t want to have that ‘going to the beach’ smell, choose a physical sunscreen.
What is your view of recent studies showing elevated levels of oxybenzone in the blood of sunscreen users?
Thanks for your great question! Thus far there have been no signs health issues from sunscreen ingredient absorption, however the recent studies pointed out that future studies are needed to learn more. One thing we do know: excessive sun exposure does cause skin cancer. Its also known that wearing a sunscreen (in addition to performing other sun safety practices) will limit the risk of cancer development.
We still advise patients to continue using sunscreen and we specifically recommend choosing physical sunscreens over chemical versions.