Beauty… Not Bullshit? Korres Volcanic Minerals Volumizing Mascara

According to Sephora, the Korres Volcanic Minerals Volumizing Mascara increases lash volume by 600%. It does not say that it “increases the appearance of lash volume by 600%”. That would be a nonsense claim, but there are so many nonsense claims in beauty that sometimes you just have to throw up your hands and sigh in exasperation. Sephora explicitly states that this “blackest, black mascara derived from volcanic soil… increases lash volume by 600 percent”.

This is interesting because this is a very specific, very testable hypothesis. Volume is a real, measurable thing. So let’s fucking test this shit.

For the purposes of this test, I am going to assume that my eyelashes are cylindrical. They probably are not perfect cylinders, but I think this should be sufficient for this investigation. For those of you who have forgotten your geometry, the formula for the volume of a cylinder is π(r^2)h, with r being the radius of the circle and h being the height of the cylinder.

I used a microscope to measure the diameter of a non-mascara-coated eyelash, and divided that in half to get the radius. Since I have already established that my eyelashes are about one centimeter (10,000 micrometers) long, I used that number as my h value. As long as that number remains consistent, my results for the volume should be acceptable.

I found that the diameter of my mascara-free eyelashes is 1 micrometer. (Gotta love simple calculations.)

Next, I looked at my Korres-coated lashes. This was a little bit messy, since some hunks of the lash were nice and thick, whereas others were much thinner. I chose a medium-thick part to represent the lash. To my complete surprise, I found a huge increase in diameter. The mascara-coated lash was a full 6 micrometers across.
For the non-coated lash: π(0.5^2)10,000= a volume of 7893.98 micrometers cubed. For the mascara-y lash: π(3^2)10,000= a volume of 282,743.34 micrometers cubed.

That’s not a six-fold increase. That’s a thirty-six-fold increase. Although it seems counter-intuitive, a five-fold increase in diameter is not the same as a five-fold increase in volume, since this is going in multiple directions (assuming a cylinder, of course). In order to get a six-fold increase in volume (so makeuped up lash = seven non-makeuped lashes), you only actually have to increase the diameter of the lash √7 times… aka 2.65 times. (If you are having trouble following, keep in mind that π and 10,000 fall out since they are on both sides of the equation. [7π(0.5^2)10,000=π(X^2)10,000; X=2.65]).

This means that this claim is not only acceptable, it is dramatic understatement. My guess for how this happened is that whoever is working in the Korres PR department saw a six-fold increase in diameter (I only found a five-fold increase in diameter, but I also only did one trial), and reported a six-fold increase in volume. As it turns out, they could have been much more bold in their claims. What originally seemed like a dramatic claim turned out to be nothing of the sort.

One really important caveat to this finding: this says absolutely nothing about how well the Korres Volcanic Minerals Volumizing Mascara compares to other mascaras. I did no comparisons, although you might be able to talk me into it. From a purely phenomenological perspective, I will note that I didn’t find that this mascara radically outperformed any of my other mascaras. It looks nice and lasts well, but I still lean towards my Clinique High Impact mascara. I am confident that many other mascaras offer a similar increase in volume to the one demonstrated here. We don’t see results that seem quite so dramatic because volume is not an easily observable trait.


1. Brilliant! I was expecting it to be complete rubbish but in fairness you can even see the difference between the two face pictures, it looks like false lashes.

2. Part of that is the curse of having blonde-tipped eyelashes!

3. Would any mascara give a similar volume increase, or is this one particularly voluminous?

4. I speculate that most mascaras would have a comparable result.

5. Great to see a Not-Bullshit once in awhile!

6. It wasn’t what I was expecting, but you can’t argue with the math!

7. Whoever you are, know that I freaking love you. (new follower here) I love hearing the science behind makeup and I love that you have the means and the curiosity to test these sorts of claims. Seriously, thanks for existing.

8. HA! You are more than welcome.

9. Beauty Not Bullshit! That’s always nice. Korres seems to make reasonably realistic claims about their products, which is… refreshing. I got a sample of this from Sephora and sadly found that it smudged like crazy on me for some reason. It did look nice, though.