skincare info

Chemical vs Physical Sunscreens

There are lots of options when choosing a sunscreen. So how can you know which one is right for you? First, you want to pick a sunscreen that has a SPF value of 30 or greater.  SPF stands for Sun Protection Factor and measures a sunscreen’s ability to protect you from UVB and prevent sunburn.  A SPF 30 will block 97% of the sun’s UVB rays. Next, you want to make sure it is broad spectrum, which means that it will protect your skin from UVA in addition to UVB.  (Learn more about the sun’s rays in our article UVA + UVB = Sun Rays).  Lastly, you need to decide what type of sunscreen – chemical or physical – you want to use to give you the protection you need every day.  Here is some information about the different types of sunscreens to help you pick the best one for you.

Physical Sunscreen

  • Also known as mineral sunscreen or inorganic sunscreen.  Inorganic does not mean that it’s not natural or good for you or the environment – it just means that it is not made by living things.  It’s made from minerals (or rocks), instead.  You can’t get much more natural that that!
  • Protects your skin from the sun’s UV rays by blocking or reflecting the light away from your skin. It’s sort of like having an invisible mirror sitting on top of your skin causing the sun’s rays to bounce off instead of penetrating into your skin.
  • Works immediately.  There’s no need to wait for it to absorb into your skin.
  • Does not breakdown when exposed to sunlight.
  • Is made from the minerals zinc oxide, titanium dioxide or a combination of both.

Titanium dioxide – has good UVB protection but is not as good at protecting against UVA rays so it needs to be used with zinc oxide or a chemical sunscreen to provide full broad spectrum sun protection.

Zinc oxide – is the ONLY sunscreen agent that can be used on its own, without any added chemicals, to protect you from both UVA and UVB rays.

  • Won’t burn or sting your eyes!
  • Will not irritate your skin.  In fact, zinc oxide is the main ingredient in almost all diaper rash creams because it is so gentle on even very delicate and sensitive skin.
  • Does not absorb into the skin.

Chemical Sunscreen

  • Also known as organic sunscreen.  “Organic” in chemistry means any chemical that contains carbon and hydrogen atoms.  It is called “organic” because these types of chemicals are made by living things.  But in the case of organic sunscreens, these chemicals are made in a laboratory - this is NOT the kind of organic you want!
  • Works by absorbing the sun’s rays. When sunlight reaches your skin, the UV rays enter your skin where the chemicals in the sunscreen absorb the ultraviolet (UV) radiation in the sun’s rays through a chemical reaction that makes the energy less powerful so you don’t get a sunburn.  This process turns the extra energy into heat and causes the chemicals in the sunscreen to breakdown.  That’s why chemical sunscreens need to be reapplied every 2 hours.
  • Must be applied 15-30 minutes before going in the sun in order to be effective.
  • Requires 2 or more chemical ingredients to provide broad spectrum sun protection – one chemical to protect against UVA rays and at least one other chemical to protect against UVB.  There is usually also another chemical added which helps make sure the sunscreen doesn’t break down and become less effective when it is exposed to the sun (which is generally NOT something you want your sunscreen to do).  Here is a list of common chemical sunscreens and their main area of UV protection (this is just a partial list but includes the most widely used sunscreen chemicals):

Avobenzone – UVA1

Homosalate – UVB

Octisalate – UVB

Octinoxate – UVB

Octocrylene – UVB

Oxybenzone – UVA2 and UVB

Ecamsule (also known as Mexoryl SX) – UVA2

Helioplex TM –UVA1, UVA2 and UVB

As you can see, Helioplex TM is the only chemical sunscreen to provide complete broad spectrum protection against UVA1, UVA2 and UVB rays.  That’s because it is made up of a combination of Avobenzone, Oxybenzone and a stabilizing agent.

  • Often causes stinging and burning if it gets in your eyes!
  • Can irritate your skin or cause rashes, especially sunscreens made with Avobenzone, Oxybenzone and Octocrylene.  This can be a bigger problem if you are also using a topical medication or cleanser to treat acne.
  • Absorbs into the skin and may act as a hormone disruptor.
  • Potentially harmful to the environment.  Oxybenzone was recently linked to the destruction of our oceans’ coral reefs. (

There is a clear winner in the sunscreen world – physical! While the majority of sunscreens on the market are chemical (they are cheaper and easier to make), physical sunscreens are safer and give better protection. So why don’t more people use a physical sunscreen? Part of the reason is education. Most people don’t even realize there is a difference between chemical and physical sunscreens. Once you know, you may decide that all of those chemicals may not be the best things to put onto or into your body, especially for girls whose bodies are still growing and developing.

For the longest time, the argument against physical sunscreens with zinc oxide was that they were really thick, sticky or greasy, super white and hard to use. But recent advances with micro-fine zinc oxide particles have led to the development of physical sunscreens with reduced whiteness and better texture but with the same great protection. We have created a wonderful, easy to use physical sunscreen with zinc oxide. It is lightweight, non-greasy, will blend well with your skin tone and doesn’t smell like you are headed to the beach! P.R.E.P. SPF 30 face+body lotion can be (and should be!) used every day, rain or shine.

Learn more about the sun in our article, 5 Sun Facts You Want to Know.

Stay healthy,

carole aponte, md

Founder & Chief Medical Officer



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