Back in 2021, the highly underrated Brooks Aurora-BL was the first shoe to get the DNA LOFT v3 midsole foam. The EVA foam is nitrogen-infused and also contains rubber and air. The following year, Brooks employed the same foam in a big update for the Glycerin 20. Brooks stans and newcomers alike praised the shoe, and its warm reception led Brooks to add DNA LOFT v3 to their two top selling shoes: the Ghost and Adrenaline, coming later in 2024. How does the Glycerin 21 stack up against older versions of the shoe and other Brooks shoes? Find out in this Brooks Glycerin 21 review.
Brooks Glycerin 21 Review
Weight: 9.8 oz / 277.8 g (US M9) | 8.8 oz / 249 g (US W8)
Stack height: 28/18 mm (midsole only) (10 mm drop)
Price: $160
Everybody loves having options, and fortunately, the Glycerin 21 is available in four varieties: Glycerin 21, Glycerin Stealthfit 21, Glycerin GTS 21, and Glycerin Stealthfit GTS 21. GTS means “go-to support” for those with stability needs and Stealthfit is a one-piece, flat knit upper that weighs less. To compare them, check out the convenient chart I so meticulously crafted below—jk, it’s plucked straight from Brooks’ site.
Ride
My first run with the Glycerin 21 felt a bit firm, but the shoe started to soften up after logging more miles. While it’s not remotely the same responsive and light ride as the Aurora-BL, it’s still a soft shoe that’s got enough energy return to where you won’t feel like you’re “sinking” into the road with each stride. I laced up the pair for a 16-miler and it was an absolute delight. What’s not to love about the shoe for a long run? It’s a plush, ultra comfy, and stable ride that takes care of your feet, resulting in a ride you’ll want to take time and again.
Depending on the shoe and the drop, I alternate between a midfoot and heel strike. The Glycerin’s 10 mm drop leads me to heel strike considerably. Which, contrary to popular belief, is not a bad thing. I promise, heel-strikers are still runners and we can still run fast. Yes, even many elites heel strike.
Midsole
The 21 added just 2 mm more foam from the Glycerin 20. 2 mm may not seem like a major change, but when it comes to running shoe stack heights, it can make all the difference. And in any case, the more DNA LOFT v3, the better. Honestly, comparing LOFT v2 to v3 is like night and day—V3 is a far superior foam, in every respect—lighter, softer, and bouncier.
If the 28/18 mm stack height seems low, it’s because it’s referring only to the midsole, and not the outsole. Companies usually include the outsole rubber in their measurements. Yes, it’s confusing. Because once you lace up the Glycerin 21, you’ll realize it’s not far off from a max cushion shoe. While the shoe’s stack height isn’t as tall, it reminds me of the Brooks Ghost Max, a true max cushion cruiser and one of my favorites from 2023. With a DNA LOFT v2 midsole, the Max has a firmer ride than the Glycerin, but the Max 2 will upgrade to DNA LOFT v3 later this year.
Upper
There’s a new, sleeker upper that delivers more structure and breathability than the 20. The engineered warp knit upper offers a very accommodating, comfortable fit. While the upper has changed, a comfy and secure upper is nothing new for Brooks, who consistently craft some of the best in the industry.
Outsole
The bottom of the shoe offers a very wide platform, providing solid stability. The pair gets a new RoadTack outsole, made of rubber and recycled silica. There’s great traction in all weather conditions, and durability will simply not be an issue. Like most Brooks shoes, you can expect to get close to 500 miles from the pair. However, I’d gladly trade in some of that durability—there’s A LOT of outsole rubber here. I think reducing a bit of it would result in an even lighter, softer, and more responsive ride. I understand the Glycerin isn’t meant for faster efforts, but that doesn’t mean the ride can’t be streamlined even more.
Weight
This ain’t your Glycerin of old where the weight consistently hovered around 11 ounces. The Glycerin 21 shed .3 ounces from the 20, and now sits below the 10 oz weight, at a respectable 9.8 ounces (US M9) and 8.8 oz (US W8). For an extremely cozy daily trainer, you really can’t ask for a better weight than that.
Looks
The older Glycerin 20 was an unquestioned upgrade over previous models on the road and on the shoe rack. It’s great, then, that the 21’s design is even more eye-catching than the already attractive 20. I received the Blue Opal colorway that tastefully blends blue and orange, bearing a striking resemblance to the iconic New York Knicks colors as well as the lesser-known Bucknell University Bison. The blend of blue and white in the midsole reminds me of those classic Firecracker red, white, and blue popsicles. Yum!
Price
Of course, there’s a price to pay for all this comfort. $160 is no small sum, but it’s the going rate for plush daily trainers like the Glycerin. When you consider the Glycerin went for $150 for many years, the price increase of $10 (in the Glycerin 20) to compensate for the addition of DNA LOFT v3 foam, is forgivable. I can still recall runs in my first Glycerin—the 17—back in 2019. It was comfy, for sure, but didn’t have nearly the smooth ride and lighter-weight feel of the 21. Same goes for the Glycerin 18 and 19.
Your word is “Glycerin”
Despite running in the shoe for nearly five years, I never knew what the word Glycerin actually meant, until I looked it up for this review. Turns out, according to Merriam-Webster, it’s a natural humectant (substance that retains moisture) often used in personal care products to hydrate the skin, hair, or nails. Interesting! While the Glycerin 21 won’t do anything for your skin, hair, or nails, your feet will sure be pampered with the shoe’s supreme softness. And with its improved, breathable upper, you won’t have to worry about your feet retaining any “moisture” from sweat or rain.
Conclusion
Brooks Glycerin 21 is not a flashy shoe by any stretch, but it’s not trying to be. As a play on “fine dining” chain Outback Steakhouse’s motto: The shoe is “no rules frills, just right.” Can’t say I’ve ever had the pleasure of ordering the iconic Bloomin’ Onion, but it’s certainly no Awesome Blossom from Chili’s. I’m joking, I’ve never had that, either. But 18-time Dundie Award winner Michael Scott sure seems to love it. Truthfully, I’ve never even stepped foot inside one of the [Googles] nearly 700 (!) Outback locations in the U.S. Am I missing out?
Well, I’m a vegetarian (Yes, I’m very…wait for it…..rare), so maybe a steakhouse isn’t the best option for me unless I want a salad with wilted greens, stale croutons, vastly overripe tomatoes, and extremely underripe cucumbers. Anyway, this isn’t a food review—where was I?
Now, to land the plane. There are ample shoes at the same price that deliver an inferior ride with half the Glycerin’s comfort and durability. If you’re looking for an above-average daily trainer to eat up daily miles in comfort, or an easy day shoe to recover from all those daily miles, the Glycerin 21 is a no frills shoe that will fit just right into your shoe rotation.
The Glycerin 21 is available to purchase online at Brooks or Running Warehouse.
Brooks graciously provided this shoe to me at no charge for wear testing. I was not compensated for this Brooks Glycerin 21 review and Brooks had no input or influence on what I wrote. Brooks did not get a chance to see this Brooks Glycerin 21 review before I published.
