Brooks Glycerin 21 Complete Review

If you're on the hunt for a running shoe that puts luxurious comfort above all else, let's talk about the Brooks Glycerin 21. For this latest version, Brooks didn't just tweak things; they doubled down on their legendary cushioning, making a fan-favorite even plusher. We've put it through its paces to give you the lowdown on whether this max-cushion workhorse deserves a spot in your rotation.

Quick Take

Overall Rating: 4.5/5

Best For: Daily training, Long distance runs, Recovery runs, Walking, Runners seeking maximum cushioning

Key Strengths: Plush and comfortable cushioning, Smooth and stable ride, Durable outsole, Accommodating fit for many foot types

Notable Limitations: Not ideal for fast-paced running or speedwork, Some users report it runs warm, Can feel slightly bulky to some runners

What Makes Brooks Glycerin 21 Stand Out?

You know what? The Brooks Glycerin 21 isn't just another yearly update; it’s a significant leap forward in cushioning. Here’s the thing: Brooks added an extra 2mm of their nitrogen-infused DNA LOFT v3 foam to the midsole. That might not sound like a lot, but it makes a world of difference on the road, turning every stride into a softer, more luxurious experience. It’s like they took their best mattress and figured out how to put it under your feet.

The new engineered warp knit upper also deserves a shout-out. It provides a structured yet breathable fit that hugs your foot just right without feeling restrictive. This combination of plush cushioning and a secure fit creates an incredibly smooth and stable ride. As one happy runner put it, "The cushioning is amazing and they feel very stable without being a stability shoe." Honestly, for anyone who prioritizes comfort on their daily miles, this shoe is a game-changer.

Real Customer Experiences

• Overwhelmingly Positive on Comfort: The vast majority of runners rave about the plush cushioning, often describing it as the most comfortable shoe they've ever worn.
• Mixed Feelings on Fit: While many find the fit accommodating, some with narrower feet find the forefoot a bit too spacious, while others have issues with the tongue design when using a heel lock.
• Consistently Smooth Ride: Users frequently praise the shoe for its smooth transitions from heel to toe, making it a reliable choice for long, steady runs.

"It's like walking on an inch and a half of marshmallow all the time." - Verified Buyer

"When I did a heel lock on them, the tongue dug into the top of my foot and was painful." - Runner's Forum Contributor

Design and Build Quality

Let me explain the nuts and bolts of this shoe. The upper is a new engineered warp knit material. It’s designed to be soft and let your feet breathe, but it also has enough structure to keep you feeling secure. Moving down, the star of the show is the midsole, which is packed with nitrogen-infused DNA LOFT v3 foam. It’s a super soft, lightweight, and responsive material that provides that signature cushioned feel.

Underneath it all, you’ve got the outsole, which uses a new RoadTack rubber. Interestingly, it includes recycled silica, which is a nice touch for sustainability, and it’s built to be durable and grip well on road surfaces. In terms of weight, a men's size 9 comes in at around 277 grams, which is pretty standard for a shoe with this much cushioning. The special tech really boils down to that DNA LOFT v3 cushioning, the warp knit upper, and the RoadTack rubber. As for durability, the main complaint revolves around some premature wear on the upper for some users.

Comfort and Fit

Honestly, comfort is where the Glycerin 21 truly shines. The step-in feel is fantastic right out of the box, with a minimal to non-existent break-in period. Here’s the thing with sizing advice: it generally runs true to size. However, if you have a wider foot or just like a bit more wiggle room for your toes, going up half a size is a common recommendation.

The width profile is quite accommodating. Brooks offers this model in multiple widths, including medium and wide, so most people can find a good fit. The standard version has a roomy toe box that prevents your toes from feeling cramped, especially on longer runs when your feet start to swell. It’s like giving your feet business class seats instead of economy. One runner summed it up perfectly:

"I've gotten in about 10 outside runs (3-6 miles) now. Good fit and feel." - Online Reviewer

Style and Versatility

Let's be real, the Brooks Glycerin 21 is not a fashion statement. Its design screams "I'm here to run, not walk the runway." It has that classic, functional look of a dedicated daily trainer. But you know what? That’s not a bad thing. It’s a workhorse, and it looks the part. Brooks offers a ton of colorways, ranging from your standard black and grey to much brighter, eye-catching options, so you can inject a bit of personality. Its versatility is its strong suit. It's obviously perfect for road and treadmill running, but because of the incredible comfort, it's also an amazing choice for all-day wear, especially for people who are on their feet for a living, like nurses or teachers.

Quality and Durability

When it comes to quality, the Glycerin 21 is a solid performer. A whopping 85% of user feedback praises its construction and materials. That DNA LOFT v3 midsole, in particular, holds up well over time, maintaining its plush feel for hundreds of miles. However, no shoe is perfect. The most common complaint centers on the durability of the engineered warp knit upper, with a minority of users reporting some premature fraying or wear. The outsole is generally seen as durable, though a few runners have noted it wears down a bit quicker than they’d like. It’s a minor issue in the grand scheme of things, but worth mentioning. As one user pointed out:

"The 21 is awful, and I had to turn it back in." - Dissatisfied Customer

Decision Matrix

Legend: ✓ = Good ○ = Average ✕ = Poor