Sun Protection Week: Day 1 – I Don’t Think I Need To Use A Separate Sunscreen

Welcome to Sun Protection Week.

I’m using “week” very loosely here because I probably won’t be able to sustain seven consecutive days of writing.

To be honest, I am very confused by whether I need to use a separate sunscreen when my moisturizer or foundation already has SPF. This should’ve been a no brainer.

Most of the dermatologist-written articles I’ve read seem consistent in saying that I need to put on sunscreen in addition to any other face base that already has sun protection.

But seriously, if you’re as oily as I am, doing the sunscreen + face base combo is like over-layering icing on a cake. The icing will slide down eventually and the whole thing will look like a mess.

Anyway, I’m not the type to take recommendations as they come so I decided to read more on this. I googled for how SPF is measured and what constitutes enough sun protection.

Apparently, SPF is determined by testing 2 milligrams of formula per square centimeter of skin.

Laneige Oil-free Sunblock Teaspoon

I took it to mean that 2 milligrams of foundation with SPF30 rating offers the same protection as 2 milligrams of sunblock with SPF30 rating if applied within the same size surface area.

Many estimate that this is equivalent to a conservative 1/3 teaspoon for the whole face, the teaspoon rule. That means that if I want to get all the SPF from my foundation alone, I have to apply a third of a teaspoon of it.

Note that the teaspoon rule is only an estimation because–

milligrams = unit of mass/ weight; while
teaspoon = unit of volume

I don’t think there’s a direct conversion of milligrams to milliliters (unless it’s the same substance) — and I’m not about to determine the density of my foundation just to get an accurate conversion of volume to mass.

Be that as it may, it’s already settled that I won’t put 1/3 teaspoon of foundation on my face. But the more important question is:

Will I put on my face 1/3 teaspoon of sunblock?
My answer is NO. That will look like me channeling my drunk inner geisha. Anyway, is there really a brand of sunblock that looks decent enough spread out on the face — at that volume??? If you know of one, tell me.

As I try to imagine it, I feel like I put the same amount of either sunblock or foundation when I wear each solely.

What I know now is — and I can not speak for dry or normal-skinned people — 1/3 teaspoon of sunblock or a combination of sunblock foundation is the same banana to me. This is what I mean by that:

amount of grease churned out by my face
1/3 teaspoon of sunblock or a combination of  sunblock and creamy anything
cake icing analogy
aka melting down face

Whatever it is that I put on my face — be it sunblock, foundation, or a mix of both — I’m sure that I always do not reach a third of a teaspoon. It would be the same less-than-1/3-teaspoon any which way I do it, every single time.

Right now, I think I’m not putting enough sun protection by derm doctors’ standards, and — gulp — I’m ok with that O.0

Although… I think I may be doing something else to mitigate sun damage… But more on that later in the week.

I have to be honest and say that I haven’t actually compared how 1/x teaspoon of sunblock looks like versus 1/x teaspoon of foundation. Maybe I’ll do an experiment on that.

What do you think?



  1. […] In Day 1, I mentioned that 2 milligrams of sunblock per cm² of skin is needed to get the SPF rating as written on the label. I don’t own a weighing scale sensitive enough to measure milligrams so I’ll be using the measuring spoon approximation. […]


  2. That’s a lot of science and math ate rae!

    If I’m in the beach, I’d happily slap more than 1/3 teaspoon of sunblock on my face. But on an ordinary day? I don’t worry that much as long as I have my umbrella and my foundation has at least SPF20. There was a time when I’d use a sunblock too but it felt too heavy, too oily and too much work.


    1. I know, I feel like the stress will age me more than sun damage will. So, I let go.


  3. Great post! I don’t even own sunscreen (lol) but ugh I have been meaning to get one, I guess I’m just really confused because I don’t know which products to buy?


    1. It’s really difficult to find one that’ll work. It took me a lot of trial and error aka money. I wanted something that looks ok on its own and under makeup.


  4. I love these kinds of topics because we have a chance to exercise our anti-marketing / anti-consumerism side a bit. I don’t think SPF is a lie, but think about it: these derma studies are bought by skincare brands. Of course they have to end with an SPF recommendation. I bet they tell you you have to reapply every hour, just so their product flies off the shelves faster.

    I think there’s truth to SPF requirement. But high-rise cave dwellers need significantly less SPF: only for their short exposure during the commute and indirect exposure while indoors. Also, skin tone factors in this. Fair-skinned people are more prone to sun damage.

    I like to draw the line at makeup. If my powder/foundation has SPF, I pat myself on the back. If not, I don’t even reach for the extra tube of SPF. I just tell myself the layer of makeup (however thin) is enough cover. If my skin was oily I’d tell myself that was enough protection, lol.


    1. I agree. I have to admit that I feel the same way — I don’t need to put that much on because I only get incidental sun exposure. But I slap a lot on when I go to the beach, probably more than needed.


  5. Biore’s UV Perfect Face Milk has negligible white cast but some makeup might not work with it. The correct amount of sunscreen really looks to much at first, but it’s something I can tolerate because I cannot wear makeup anyway.


    1. I currently have 4 sunscreens/blocks in rotation but I’ve been meaning to try Biore since I read of your review on Perfect Face when I back-tracked. My fave sunblock is also mostly zinc oxide and Perfect Face seems like a good alternative.


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