The New MAC Mascara’s Clump-Free and Buildable Formula Promises Bigger Lashes—So We Tried It

Whenever I’m about to apply another coat of mascara, I wonder, “Will this coat be the coat that makes my lashes clumpy?” Nine out of 10 times, the answer to this question is “yup.” I’ve used countless mascaras, and I usually don’t go beyond two coats. But thanks to the new MAC Stack Mascara, this no longer has to be case in my quest to have bigger and bolder lashes (without the clumps).

While MAC has come out with dozens of mascaras over the years, (including the Extended Play Mascara Gigablack Lash which I have praised on repeat) none may be more innovative than its latest release, IMO. The MAC Stack Mascara, which launched early this March, allows you to apply near-endless coats to your lashes without them sticking together or becoming a clumpy mess. You can add volume to the Nth degree and customize the look of your lashes based on your makeup for the day. The results seem like magic, but they’re actually the product of a carefully constructed formula two years in the making.

MAC Stack Mascara — $28.00

The mascara uses a mix of Vita Gel (for buildability), Fibre Melt Technology (for a flake-free finish), and Lash Flex Polymer (for a long lasting-hold). Together these form the building blocks for a clump-free lash solution.

As a bonus, the mascara has not one, but two different brushes you can choose based on your lash type. The Mega Brush is narrower and ideal for coating longer lashes, while the Micro Brush is thicker and perfect for adding definition to shorter lashes. The bristles are short and staggered, making it easier to comb through and separate each of your lashes.

Sounds good, right? We wanted to see if the mascara (we all tried the Mega Brush) really lives up to the hype, so the commerce editors at Well+Good put it to the test. Keep reading to find out our final verdict and what the mascara looks like on different lashes. 

Taylor Bell. - Sr. Commerce Writer

I love this mascara for two reasons: one, it really doesn’t clump. I noticed this almost immediately from the way the product settled onto the brush. Tip: If a mascara begins to lump together or thicken on the bristles before you apply it, that isn’t a good sign. I often find this happens when using volumizing mascaras or larger spoolies since they pick up a lot of product. But that wasn’t the case with the Stack Mascara. The product doesn’t clump onto the brush, so you can easily coat your lashes over and over without the mascara becoming too thick in consistency.

Secondly, the Mega Brush separates every. single. lash. It’s a game-changer for anyone like me who has thick lashes that naturally curl up and stick together. The brush combs through your lashes from root to tip and perfectly rakes them in just a few strokes. I was able to apply two coats and go back in for touchups after without my lashes binding together. All in all, it’s a solid mascara if you want something that is versatile that you can wear to touch up your face on no makeup days or for a night out. As a bonus, it’s easy to remove. I used a standard makeup wipe and the mascara lifted completely without me having to do a second cleanse.

Gina Vaynshteyn - Sr. Commerce Editor

“If you’re looking for a clump-free mascara that adds volume and length, try MAC Stack. Not only is it easy to apply (the formula is smooth, but not so inky that it leaves smudges on your eyelids the second you, heaven forbid, blink), but the longevity is impressive. I took this for a spin to my hot yoga strength training class (60 minutes of non-stop sweating in a hot room) and It. Did. Not. Budge. I was fully expecting to come out of class looking like a raccoon, but my eye makeup stayed put (also a big s/o to Stila Stay All Day liner—you didn’t let me down, either).  Love that this mascara gives me bigger, bolder lashes that made my hazel eyes pop on Zoom. It’s also easily buildable. Great for an everyday mascara.”

Francesa Krempa - Commerce Writer

“I’m really picky about mascara because my eyelashes seem to clump so easily. This one is really effortless and natural—I love how it coats each strand individually and doesn’t leave me in a chunky, overdone mess. Really impressed!”

Want to be the first to hear about the latest (and greatest) SHOP product drops, custom collections, discounts, and more? Sign up to have the intel delivered straight to your inbox.