Physical Sunscreen vs. Chemical Sunscreen

By Lela Lankerani, MD June 26, 2018 No Comments

chemical vs physical sunscreen

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).

Choosing a sunscreen, however, can be difficult since there are so many different types to choose from. There are two types of sunscreen formulations to choose from – physical sunscreens and chemical sunscreens.  Some products are a hybrid of both types.

What Is Physical Sunscreen?

A physical sunscreen (sometimes called mineral sunscreen or sunblock) uses minerals such as zinc oxide or titanium dioxide to deflect UV rays away from the skin. These formulations literally sit on the skin and block or scatter UV radiation before it can penetrate the skin.

There are several benefits of using a 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

However, there are some cons to 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

What is Chemical Sunscreen?

Chemical sunscreens (sometimes called chemical absorbers) use chemical carbon compounds that convert UV radiation to heat, which is later released from the body. Common ingredients of chemical sunscreens include oxybenzone or octinoxate.

Some benefits of chemical sunscreens include the following:

  • 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

Drawbacks 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.

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.

 


Lela Lankerani, MD

Lela Lankerani D.O. received her undergraduate degree in Biology at Washington University where she graduated cum laude. Dr. Lankerani has published articles in several scientific journals and has presented at national scholarly meetings including the American Academy of Dermatology and American Osteopathic Academy of Dermatology.


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