Fifty shades of burnt
Now that the weather is getting warmer, it’s time to talk about sunscreen.
You’ll notice from my profile picture that I am pale. Redhead. Ginger. Ranga. Whatever you want to call me, the bottom line is, the sun and I don’t get along.
I’m not sure if my decision to move to the sunniest continent on earth was the best for my skin’s health, but while I’m here I’ll make sure I keep myself protected. And the government wants to keep all Australians protected too.
Two in three Australians will be diagnosed with skin cancer by the age of 70. The cost of skin cancer in Australia is immense. Hospitalisations due to skin cancer make up one quarter of all cancer hospitalisations.
But how many Australian adults know how sunscreen works? And how much sunscreen is recommended for application? It’s almost definitely more than you’ve been using.
Go find an old sunscreen bottle, flip it around, and read the ingredients list. It’s usually a long, tongue twisting list.
Never fear, those lists don’t have to be so cryptic. The basic sunscreen ingredients are:
- The molecules that provide the protection from the sun’s rays.
- Preservatives to keep the protection molecules working for a long time. Sunscreen is usually designed to stay stable for up to 3 years.
- Emulsifiers, or ingredients that keep the ingredients of a sunscreen mixed together.
- Added fragrance or dyes like those that give some sunscreens that nostalgic smell I know too well.
There are two types of sunscreen: chemical and physical. They differ in the types of compounds that provide protection from the sun.
Chemical sunscreens are organic. But not vegetable organic, chemistry organic.
In chemistry, the term organic means carbon based. These molecules in chemical sunscreens provide protection by absorbing light.
Physical sunscreens are inorganic, or not carbon based. They use metal particles containing iron and aluminium for protection. Depending on the size of the metal particle they can reflect or absorb light.
The metal particles in the sunscreen reflect light in a way that creates that classic white nose. The bigger the particle the whiter the nose. Source: Pixabay via chezbeate
We used to think these particles only reflected light, or blocked it completely from reaching the skin. These products were often called sunblock. But this term is now banned in Australia because it is misleading. No type of sunscreen can block or absorb light 100%. However, the names sunscreen and sunblock are often used interchangeably.
Not all light energy is harmful to our skin. We can’t get sunburned sitting indoors next to a lamp thank goodness. The type of light that causes skin damage is ultraviolet (UV) light.
Damage from UV light comes in many forms from sunburn and tans to premature wrinkles and cancer. UV light itself is split up into three different forms, or wavelengths: UVA, UVB, and UVC. Luckily, earth’s atmosphere filters out UVC so we don’t have to worry about it.
When sunscreen was first developed it only blocked UVB light, because UVB light is the type that causes sunburn. We thought if we prevent burns we prevent cancer. However, it’s not so simple. Both UVA and UVB light contribute to skin cancer.
While UVB light causes damage to the outer layers of skin, UVA light penetrates deeper. UVA light causes premature aging, wrinkles, tanning.
Don’t be fooled, sunburn does not turn into a tan. It just seems that way because you can’t see the tan until after your sunburn fades. And trying to get a base tan for protection the rest of the summer doesn’t work. A natural tan only provides between 2-4 SPF. There is no such thing as a healthy tan as it doesn’t provide any long-term defence against cancer. The reality is, that no matter your skin tone, you need to protect your skin.
What is SPF anyway?
Those numbers on the front of sunscreen bottles can give you an idea of how much protection it provides. The sun protection factor (SPF) is a general measure of how long you can be out in the sun before reapplying. Take my skin for example. Unprotected, I start burning in only 5 minutes. If I’m wearing SPF 15, theoretically I won’t start burning for 15 times as long. I say theoretically because most people, including me, don’t apply the same amount of sunscreen as researchers do during testing. That’s why it’s recommended you reapply every 2 hours.
When sunscreen is tested to determine its SPF, researchers apply 2 milligrams of sunscreen per square centimetre of skin. This translates to about 30 millilitres or one full shot glass of sunscreen to cover all the exposed areas of your body.
I don’t recommend drinking your sunscreen either. Source: Flickr via Rob Nguyen
Do you still have that sunscreen bottle next to you? I dare you measure out a full 30 millilitres of sunscreen. I can almost guarantee you’ve never put that much sunscreen on at once.