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.
- 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.
- 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):
- 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. (http://link.springer.com/article/10.1007/s00244-015-0227-7)