This is exactly how much foundation with SPF you'd need to wear to get enough sun protection.

There’s something you should know about me… I’m big on face sunscreen.

There are a few reasons why I wear sunscreen on my face every single day – I have freckles, burn easily, and frankly, I don’t want my skin to look UV damaged.

Oh, and my dad’s had several skin cancers, and I’m a scientist working in clinical research, with an honours degree in pharmacology of melanoma treatment. I also run an Instagram account (ms_hannah_e) dedicated to incorporating sunscreen into beauty routines.

Yep, I’m that dedicated.

A post shared by beauty science skin / Hannah (@ms_hannah_e) on Mar 21, 2019 at 11:57pm PDT

A post shared by beauty science skin / Hannah (@ms_hannah_e) on Mar 18, 2019 at 12:19am PDT

A post shared by beauty science skin / Hannah (@ms_hannah_e) on Feb 15, 2019 at 1:32pm PST

Did you know, though, that most people don’t use enough sunscreen? Or don’t know that it’s not OK to just wear a foundation or tinted moisturiser with a bit of SPF in it?

Let me break it down for you – the Therapeutic Goods Administration (or TGA, Australia’s regulatory body for sunscreens) has very strict guidelines about what products can and can’t say they’re a ‘sunscreen’.

To market a product as sun protection in Australia, the brand must prove their sun protection factor (SPF) is as labelled by passing a standard test which involves applying a precise 2mg of product to every square cm of skin.

Only once it’s jumped through these very necessary hoops can a bottle have the letters SPF on the front. But when it comes to protecting your skin from the sun, that’s only half the picture. According to the TGA, sunscreen is only effective if applied correctly and thoroughly.

But what does that actually mean? In practice, it means putting on at least one teaspoon of sunscreen on each area of the body. Face, neck, and ears count as one area. If you normally reach for a foundation or tinted moisturiser with SPF included, you’ll need even more.

Want to know more about facial sunscreens? Mamamia’s beauty guru Leigh Campbell explained the difference between chemical and physical sunscreens, and which one you should put on your face, on the You Beauty podcast. Post continues after audio.

If you’re anything like me, you probably read that and thought, I maybe use half that… Or worse, none at all.

I understand why. About a decade ago, sunscreens went and got themselves a bad rep because of thick, greasy formulas that left you looking like a sweaty ghost. Instead, people turned to BB creams with SPF 20+ or foundations with SPF 15+ instead of applying a dedicated SPF 50+ sunscreen underneath their makeup.

Brands have come a verrrrrry long way, though, and the sunscreen formulas of 2019 are bloody brilliant (more on that a bit later). Still not convinced?

Thought that might be the case, so I decided to get out my trusty IKEA teaspoon to measure out exactly how much foundation with SPF in it you’d need to wear to get enough sun protection.

My current foundation is the IT Cosmetics Your Skin But Better Illuminating CC Cream SPF 50+. First, I measured out the amount of product I usually wear everyday, remembering you need at least one teaspoon of SPF for your face, ears and neck.

It works out to be around one pump (the IT Cosmetics CC Cream is quite high coverage), which only fills up a tiny bit of my teaspoon.

Next, I measured out exactly one teaspoon of the same product. That’s 14 whole pumps of my foundation.

This is how much I would need to use for my face, neck, and ears combined to get the labelled protection according to the TGA’s Australian standards.

I then put that one teaspoon of foundation on my face, and I'm not exaggerating when I say the result was mortifying.

Find me a person who would actually leave the house with this much foundation on and I'll give you a pat on the back, because I looked and felt disgusting wearing this much foundation.

I even let it set for an hour, and it still looked this wet. That’s not highlight.

I wanted to be thorough, so I asked makeup artist Iain Jeffery if there might be a technique to make this much foundation wearable. He said, “No, it’s impossible. Pigment builds too quickly to make it work.”

The other thing to note about wearing this much foundation to get enough sun protection is the cost. This particular IT Cosmetics CC Cream costs $61, and using this amount everyday (and every two hours if reapplying diligently) is a really easy way to waste a lot of money.

Basically, what I'm trying to say is, please don't rely on your makeup for sunscreen.

It's much cheaper to buy a separate sunscreen and apply makeup over the top, and the result will look a lot more normal than I did in the photos above.

To make it even easier for you, here are my favourite sunscreens that wear beautifully under makeup:

Ultra Violette Queen Screen SPF50+Luminising Sun Serum, $47.

Invisible Zinc SPF 50+ Sheer Defence Facial Moisturiser, $34.

Mecca Cosmetica To Save Face Superscreen SPF50+, $40.

Feel Good Inc. Sensitive Sunscreen Lotion SPF50+, $27.95.

La Roche Posay Anthelios XL Ultra-Light Fluid Facial Sunscreen SPF50+, $29.95.

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For more handy advice on getting your act together with facial sunscreen, read these below:

• Physical or chemical sunscreen: How to know which type of sunscreen to put on your face.
• We've just learned a genius way to reapply sunscreen over makeup and OMG, problem solved.
• The one skincare product that will save you thousands over your lifetime.