I’m an average Joe. I don’t make mascara. I don’t test it. I’m not a chemist. But I do loooove me some research.

Today, I was wondering how mascara worked. From reading the ingredient lists, I already knew the things that went into that tube. But why? What did these ingredients actually do?

Today, I’ll share everything I learned. But here’s the short answer:

Mascara works by using a mixture of water, waxes, oils, and pigments to coat each lash with a black paste. This makes each lash look bigger because the lash has been coated with a substance that thickens it. It also makes each lash look longer because natural lashes can tend to taper off at the end, and mascara adds both color and volume to the lash tips. Finally, it makes lashes a more prominent feature by using pigments to make them darker.

But that doesn’t really tell you the full story. Let’s get into more specific detail on what each ingredient does.

Mascara Ingredients and Their Functions

If you’re anything like me, “mascara works by coating lashes” isn’t a good enough answer for you. So I did some diving into what ingredients did what.

Disclaimer: it’s probably not perfect, but this is what I’ve gathered from endlessly scouring the internet and drawing my own conclusions from the research.

Water

Water is the main ingredient in lots of mascaras I looked at. The exception is waterproof mascaras, which usually have emollients like isododecane at the top of their list. (By the way, want to remove your waterproof mascara without makeup remover? There’s a post for that.)

The function of water in a mascara, which I infer from this article from Byrdie, is to help the dry-down time for mascara once it’s on your lashes.

Having water in your mascara also helps you take it off at night. I think all of us know that washable mascara, meaning mascara that’s not labeled waterproof, comes off pretty easily when it gets wet. Water as the main ingredient makes that so.

It’s both a blessing and a curse to have mascara come off easily, and we have water to thank/cuss at for that.

Here are the ingredients for my favorite mascara, It Cosmetic’s Superhero. You can see water at the tippy top of the list.

Waxes

Waxes are a thickening agent, and they’re what’s responsible for volume and holding curl. They help with the mascara’s staying power, too. And waxes are good at clinging to pigment, which means a richer color deposit on your lashes.

Most of the mascaras I’ve seen have beeswax (AKA Cera alba) listed somewhere. But there can be plenty more waxes involved too, like carnauba and rice bran wax.

Here are some waxes found in Lancôme’s Monsieur Big.

Oils

With all those waxes, cosmetics companies will need to thin out the formula so that it’s not clumpy. Oils are in the emollients category, which means they help with the spreadability of a product.

Having an oil-heavy mascara seems like a recipe for smear city, doesn’t it? You might wonder why companies don’t leave the oil out and let the water do the work of thinning the formula.

The trouble is most waxes aren’t water-soluble, meaning they won’t blend nicely with the wax.

Waxes are mostly lipophilic, meaning lipid-loving. And what are lipids? According to The Free Dictionary, they’re “a group of substances comprising fatty, greasy, oily, and waxy compounds” (emphasis mine).

Simply put, oils and waxes like each other and blend easily. And since oils are less viscous than waxes, they’re what will make the mascara more of a liquid than a solid.

(Note: Since water and oil/wax don’t blend, I wondered why mascara didn’t separate in the tube. I couldn’t find a good answer online for this.)

Here are some oils found in Milk Makeup’s Kush Mascara.

Pigments

What would mascara be without pigments? If you’re asking “how does mascara work,” you should know that darkening your lashes is a key component.

You’ll find a lot of pigments in some mascaras, but there’s one main pigment that serves as a common thread throughout all mascara formulas I looked at: iron oxide. And you’re not wrong in what you’re thinking right now; yes, rust is a form of iron oxide.

Scary to think of, but never fear. There are different types of iron oxide, so it’s not the same as getting a chunk of rust in your eye. If something is being sold in a retail store and has been for decades, as is the case with iron oxide, you can be sure it adheres to FDA regulation and is safe for your eyes. (And as an aside, the type of iron oxide we’re talking about isn’t reddish brown. Predictably, it’s black in color.)

Another pigment you may see in mascara is carbon black. That’s not a slick marketing term for blackest-black. Carbon black contains actual carbon. And unlike iron oxide, which has been around forever, carbon black (AKA D&C Black No. 2) was banned until its reapproval in an FDA’s Code of Federal Regulation published in 2004. Its use is still controversial—Safe Cosmetics, for one, is not a fan. Maybe stay away if you want to play it safe.

Here’s iron oxide and some other pigments you might find on an ingredient label. This one’s from Benefit’s BADgal BANG! mascara.

Polymer Fibers (Optional)

Some mascaras work by adding length to your lashes, and this is best achieved by the inclusion of synthetic fibers in the formula. These fibers, made of rayon, silk, or nylon, get on the mascara wand and attach themselves to your lashes, extending the length at the tip. They also help with water-resistance.

These types of mascaras are called fiber mascaras. Easy to remember, right? You can know them by either their advertising or by their ingredient list. If you have something called a copolymer in your ingredient list, you have fibers in there. And if they’re really high up on the list (as in it’s listed second), you might have a tubing mascara on your hands, which we’ll discuss in a second.

Here are the ingredients for one of my favorite mascaras, Maybelline’s The Falsies.

Polymers That Tube (Optional):

Have you ever heard of a tubing mascara? This is a type of mascara that works by formulating polymers, which we just discussed above, to wrap around your lashes like a tube.

Because polymers add so much to the mascara’s moisture resistance and because the formula gets wrapped around your lash instead of painted on like a paste, you get major longevity from tubing mascaras. No flaking or smearing under your eyes. (I’m the queen of undereye smudging, and I can vouch for this claim.)

The annoying thing about tubing mascaras is that they seldom advertise themselves as such, so you’ll need to find a good, complete list online to figure out which ones are and which ones aren’t. I haven’t found that list yet, so good luck. Maybe I’ll make it one day.

The other way to tell which mascaras are tubing and which aren’t is to look at their ingredient lists. I did this with three tubing mascaras—No7’s Stay Perfect, Thrive Causemetic’s Liquid Lash Extensions, and Maybelline’s Snapscara—and each had copolymers as the second ingredient.

Here’s the ingredient list for Maybelline’s Snapscara.

Mascara Component Features and Their Functions

The Wand

The mascara wand, besides being a great name for a blog, is one of the most important features of how mascara works.

The same mascara formula can perform differently—and I mean completely differently—depending on the wand type. In no other cosmetic product does the component contribute more to the performance of the product.

Let’s go over some features of mascara wands.

Brush Material

If you’re a mascara lover, you’ve probably noticed that the brushes are made of one of two things: natural bristles or plastic. Let’s look at some mascara wands you’ve seen already in this post:

You’ll naturally find your own preference for which you prefer. Luckily, mascara packages almost always show what the wand looks like because they know it’s a huge selling point for the mascara.

I strongly prefer bristles because I find plastic not only coats my lashes too thinly but also—yikes—pokes me in the eye. It legitimately hurts. But other folks don’t have these troubles and love their plastic wands, so be sure to try different types!

Brush Shape

We just talked about how the brush material can differ. But what about the shape? Here are some different ones.

A normal shape is a good place to start off. The one pictured is a little plump. Some are a bit thinner than this, like the one in the previously mentioned It Superhero. This brush shape works by grabbing most of your lashes with minimal clumping, but it isn’t always as precise as something tapered.

Hourglass wands are synonymous with volume. I’m honestly not sure how the wand does it, but most mascaras that are known for huge volume have this shape brush. That’s your go-to shape if you want to look like you have a curtain of thick lashes.

The micro shape is great for definition. It works by having small, separated bristles that make sure each lash is separated from the next and stays that way. You’ll trade volume for those benefits, though.

Curved brushes, if aimed right, follow the shape of your lash line. It makes applying mascara fast if you get it right but messy of you don’t. That’s why it wouldn’t be my first choice for beginners.

Tapered and conical brushes are meant to have the benefits of a normal shape with the added bonus of being able to get those baby lashes in the corner. Those tapered end acts as precision tools. The trouble is the bristles aren’t very long and collect a lot of product, so you can wind up with clumps.

And finally, we have the gimmick. These are plain ol’ weird brushes that befuddle even seasoned mascara users. These wands work by using your curiosity to steal your money. Don’t fall for it without watching unsponsored reviews on YouTube.

The Wiper

Finally, we have that little piece in the tube that scrapes off excess product: the wiper. Too small, and it will remove too much product, leaving you frustrated as you try to get results with little to work with. Too big, and you get masses of product on the brush, resulting in a clumpy mess.

That’s why it’s so important for manufacturers to get this component just right—it can be the difference between the perfect application or an enraging experience.

Closing Out

Well, that’s it folks. That’s everything I learned about how mascara works. I hope this information helped you get one step closer to really understanding the mechanics of exactly how mascara gives you those beautiful results.