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Maths 101: How To Dosage Your Skincare

Skrivet av Isabel Järnström 16.10.2019

Maths 101 How To Dosage Your Skincare

How do you get your skincare dosage right for the skin of your dreams?

Skincare ingredients remain the focal point in the modern-day beauty sphere, with labels on crème jars and serum bottles clearly stating what key ingredients are added, what the blends do, and more importantly, in what strength (percentages) they arrive in.

See more on skincare ingredients in: ‘Do Your Skincare Ingredients Actually Work.’

Although skincare connoisseurs have long since cracked the ingredient code – rambling up the separating traits between AHAs, BHAs, and PHAs in their sleep, and are well aware of the fact that hyaluronic acid isn’t really an acid, the dosage can be a tricky riddle to solve.

As it turns out, mathematics and skincare have more in common than you thought. If you want to achieve the skin of your dreams, you should head back into the classroom and start taking notes.

You see, 20 % Vitamin C does not mean it’s more potent than 10 % Vitamin C.

Confused but curious?

Let’s decipher some of the dermatologists’ favorite ingredients in skincare:



The go-to AHA for topical exfoliation does its deed at a percentage level between 3 – 5 %.

But there’s a catch: to keep the product’s pH level in mind.

A high pH level prevents skin irritation but also weakens the strength of the acid.

E.g: a 5 % glycolic acid concentrate with a high pH level lowers the concentrate to around 2 %.

Ideal pH Level? Keep it no higher than 3 - 4 %. Check the chosen product’s brand website for info about the pH level as it’s not always listed on the bottle.



Acne sufferer’s hero ingredient has been proven to be strong, where as little as 4 % is powerful enough to target skin concerns like redness, uneven skin tone, and large pores.

There are however 10 % niacinamide products, which are totally fine to use.

What you should be aware of is that your product of choice clearly states what percentage the niacinamide arrives in. If it’s not spelled out, it’s probably an insignificant amount, which ultimately, does nada for your skin.



To master the dosage of retinoids, you need to know what type you’re dealing with.

There are 3 types of retinoids:

1.     Pure retinoic acid – the strongest, prescription-only alternative

2.     Retinol – weaker (but still effective) and less irritating than pure retinoic acid

3.     Retinyl palmitate – the gentlest one in the retinoid family

To spell it out clearly, a 10 % retinyl palmitate serum is weaker than a 5 % retinol serum.

What should you do to get the dosage right?

If you’re familiar with The Retinoids Family, you know they’re a highly effective but aggressive bunch.

Introduce your skin to retinyl palmitate – the gentlest family member and build up your skin’s tolerance (and enough confidence) to work your way up to the middle sibling – retinol.

If your dermatologist prescribes you a pure retinoid acid, go ahead and use as instructed. 



Vitamin C is a fickle but powerful ingredient – if packaged with care, where stability of the ingredient is more important than its percentage.

A stable 5 % Vitamin C serum is more potent than a 25% Vitamin C serum that isn’t stable.

Since Vitamin C is sensitive to light, heat, and air, and does not thrive in water, investigate the:

1.     Formula – make sure the Vitamin C is either water-soluble or arrives in a waterless formulation.

2.     Packaging – ensure that the Vitamin C is cleverly packaged, e.g. delivered in capsules or separate caps that are complemented with a serum.


Studying mathematics isn’t so bad after all, is it?

Now, let's move on to the "Ingredients That Actually Work Wonders For Your Skin"