Shot glass, one teaspoon, quarter teaspoon, three fingers, two fingers… where??
“Everyone wears just the right amount of sunscreen,” said no dermatologist ever. I bet it’s something for dermatologists wish they would say, though. But no matter how many stories about the right application of sunscreen affect social media or in the news every year, most of us are not wearing enough to be marked SPF 30, SPF 50 or SPF100 on the package.
Part of the problem is that most of us have never thought about how sunscreen companies determine the SPF level of each sunscreen formula.
Why is that important?
Because basically what do we need to do see do to get the same effects of UV protection.
Obviously, testing the quality of sunscreen for UV protection is more complicated than one step, but this is the only one we need to try to repeat:
When determining the formula factor of sunscreen, sunscreen is used in the intensity of two milligrams of sunscreen per square centimeter of skin.
Translating that into how much we need in different parts of the body is hella MATH-y, so experts rely on measurements of teaspoons, gun glasses, golf balls, finger lengths, etc. — all official indicators — to give us a general idea of the amount to use.
PATTERNS OF SUN ACCESS USE, FOR HEALTH IN CANADA
I admit, I didn’t realize Health Canada’s sunscreen guidelines actually list the appropriate amount for each body part until about six minutes ago. Back in 2019, Health Canada released this short video about how much sunscreen adults should be applying for optimal UV protection:
The proper use of sunscreen according to Health Canada is as follows:
- 1 teaspoon for face and neck
- 1 teaspoon per arm
- 1 teaspoon per leg
- 1 teaspoon on the front of your torso and
- 1 teaspoon on your back
SUNSCREEN MAT FOR GOOD UV PROTECTION
A teaspoon is equal to 5mL, so 7 teaspoons add up to 35mL – that’s important math when you think about the size of the tubes or bottles of sunscreen you use and how many you go through on vacation or during the summer, or during the year if you wear it every day (of course you do).
Be careful: although the upper chest or décolletage is not specifically mentioned in the Health Canada guidelines, a teaspoon is enough for the face, neck, ears. again any skin exposed on your neck.
HOW MUCH SHOT-GLASS NEEDS TO SEE THE SUN?
For years I have been told by dermatologists that adults need full body sunscreen. There’s no shot glass size, exactly, but it’s usually about 44mL if you live in the US and about 30mL if you live in Canada. Health Canada recommends a total of 35mL when measuring with a teaspoon (which you should do if you’re not good at physical measurements), though overall it depends on how tall and curvy you are. (Of course, it’s best to overestimate the amount you need if you think you’ll need more than a “sizeable” person. Sunscreen guidelines usually say to apply sunscreen liberally, after all.)
HOW TO USE SUNSCREEN ON YOUR FACE
For the past few years, I’ve been adamant that we need 1/4 teaspoon of sunscreen JUST FOR FACE, a dosage tip I first heard from cosmetic chemist Dr. Michelle Wong, aka Lab Muffin Beauty Science. It’s below Health Canada’s recommendation, but Michelle explains where her numbers come from and does all the math in this blog post and video here:
I never will. It hurts my brain, all this math + art + creativity. But I find my face and Michelle’s face aren’t that different in size, so if I can, I use an actual 1/4 teaspoon to measure my sunscreen on my face, and use another 1/4 teaspoon on my ears, neck and the little bit of skin exposed by the boatneck tops I wear when I travel. (When I don’t use a measuring spoon, I tend to overdo it, and get accused on Instagram and TikTok of using a whole tube of the stuff on my face.) I double the amount of my forearms, and triple it on the rare occasions my arms are fully exposed.
HOW LONG IS TWO FINGERS TO LOOK AT THE SUN?
If you’re into social media, chances are you’ve heard of Jude Chao the three-finger method of measuring sunscreen to protect your face. Since his post in September of 2019, it has become known that two finger method for people with fingers bigger than Jude’s (wow, this it does sounds weird, but whatever). Either way, it is initially based on 1/4 teaspoon Recommended for the face, this method has been really helpful for many people who have not been using it enough.
However, finger length measurements are not arbitrary because the number of people who squeeze their fingers varies slightly, as does the actual size of people’s fingers. (Some guy on TikTok confirms that one The length of a finger is enough, but his fingers are big! I’ll add a link to that video when I find it again.) Sunscreen consistency is also important; some formulas are too small to be extracted this way.
BEST PRACTICES FOR USING ADEQUATE SUNSHINE
It’s simple enough: your best bet is to get your head around the right amount of sunscreen you need measure yourself at least a few times. I have already mentioned that I do it myself, and it really helps.
In fact, whether you hide your SPF supplies in the bathroom or by the front door, keep measuring spoonfuls of your sunscreenso you can measure before applying, and later use the spoons as visual comparisons.
If you haven’t used much sunscreen before, the right amount will feel like a lot more than you’re used to. Applying that much can be difficult if you are using a liquid formula rather than a thick cream type. A simple application tip: a sunscreen that is smooth on the skin in layers. Also consider Jude’s method of applying cushion puffs made of hydrophilic polyurethane (PU), designed to apply liquids and creams smoothly without absorbing the product.
It is important: use sunscreen about 15 minutes before sun exposure giving the formula time to dry and set on your skin so it stays put as you move around. If you apply sunscreen before getting dressed, give the application enough time to dry so it doesn’t rub off on your clothes.
And if you use sunscreen, remember:
- the back of your neck
- behind your ears and your ears themselves
- any skin exposed on your neck
- your ankles if your pants or leggings are off
- the back of your hands
- the top of your feet if you are wearing flip flops or sandals
- on the soles of your feet when you spend time at the pool or beach
- reapply sunscreen to towel-dried skin after swimming or sweating profusely
- reapply sunscreen every two hours
I GO TO YOU
Did you know that Health Canada has this information about how much is a sunscreen application screen on their website?
How much sunscreen do you usually put on? Do you measure it? Do you or can you continue to measure the equipment with your sunscreen?
And how successful are you at remembering to use sunscreen in those tricky places? (No judgment fails from time to time; I have them too!)
