REASONS TO BUY
Stable
Suitable for cool weather running
Reliable
REASONS TO AVOID
Clunky-feeling outsole
Lacks breathability
Not responsive
Brooks Glycerin 21 - Women's Review
This revamped shoe provides extra cushioning but falls short for speed, making it suitable for leisurely walks rather than high-paced runs
While not our top pick for runners, the Glycerin is a comfortable wear all day shoe when comfort is your top priority.
Credit: Natalie Kafader
RELATED: Best Running Shoes for Women of 2024
Our Verdict
The updated Brooks Glycerin 21 rides differently than versions past in ways that will appeal to some and repel others. With its 10mm drop, additional cushion, and lack of breathability, this shoe ultimately fell from our good graces this time around. It's got a solid and semi-supportive lateral feel, but it's a bit on the chunky side, which makes it feel a bit sloppy to run in. Suitable for taking it easy on your feet during long walks and plodding excursions, the refurbished Glycerin is not a speed demon. If you are a die-hard Brooks fanatic and want a warm winter shoe that will keep you company on your long runs, the Glycerin might be worth your while. If a supportive and traditional-feeling piece of gear is on your radar, the Glycerin will do the trick, but it does not top our list of recommendations.
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 This Product
Brooks Glycerin 21 - Women's | |||||
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| Awards |  |  | |  | |
| Price | $159.95 at Backcountry Compare at 3 sellers | $139.95 at Amazon Compare at 2 sellers | $160 List $129.95 at Amazon | $139.95 at Backcountry Compare at 3 sellers | $120 List $86.40 at Amazon |
Overall Score  |
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| Star Rating | |||||
| Bottom Line | This reconfigured classic offers extra cushioning, but is more geared towards leisurely walks than high-speed runs | This running shoe offers the performance technology and comfort needed to be your go-to shoe, no matter your running goals | With strong responsive bounce and enough comfort for long runs, this shoe will suit marathon hopefuls and speed demons alike | The structure and comfort of this shoe make it a highly recommended option for long distance runners who want a reliable road running steed | While not a race-focused shoe, this affordable and bouncy option will keep your legs turning over quickly and easily |
| Rating Categories | Brooks Glycerin 21... | Asics Novablast 4 -... | Puma Deviate Nitro... | Brooks Adrenaline G... | Saucony Kinvara 14... |
| Cushioning and Landing Comfort (25%) | |||||
| Responsiveness (25%) | |||||
| Stability (20%) | |||||
| Upper Comfort (15%) | |||||
| Weight (15%) | |||||
| Specs | Brooks Glycerin 21... | Asics Novablast 4 -... | Puma Deviate Nitro... | Brooks Adrenaline G... | Saucony Kinvara 14... |
| Weight (per shoe, size 6.5) | 7.86 oz | 7.36 oz | 7.02 oz | 8.21 oz | 5.55 oz |
| Style | Neutral | Neutral | Neutral/race | Supportive | Neutral |
| Sizes Available | 5 - 12 US | 5 - 12 US | 5.5 - 11 US | 5 - 13 US | 5 - 12 US |
| Measured Heel-to-Toe Drop | 10 mm | 9 mm | 8 mm | 12 mm | 5 mm |
| Measured Heel Stack Height | 28 mm | 40 mm | 34 mm | 34 mm | 30 mm |
| Measured Forefoot Stack Height | 18 mm | 31 mm | 26 mm | 22 mm | 25 mm |
| Claimed Heel-to-Toe Drop | 10mm | 8 mm | 6 mm | 12 mm | 4 mm |
| Claimed Heel Stack Height | Not stated | 40.5 mm | Not stated | Not stated | 31 mm |
| Claimed Forefoot Stack Height | Not stated | 32.5 mm | Not stated | Not stated | 27 mm |
| Measured Outsole Length | 10.50 in | 10.65 in | 10.31 in | 10.50 in | 10.13 in |
| Measured Outsole Width | 4.30 in | 4.32 in | 4.00 in | 4.25 in | 3.96 in |
| Upper | Synthetic mesh (59.7% recycled) | Engineered knit mesh | Mesh | Engineered air mesh | Mesh |
| Midsole | DNA Loft v3 | FF Blast Plus Eco | Nitro/Nitro-Elite | DNA Loft v2 | PWRRUN, PWRRUN+ |
| Outsole | Rubber | AHAR outsole | PumaGrip ATR Rubber | Rubber | XT-900 rubber |
| Measured Outsole Hardness | 50 HA at toe, 70 HA rest of shoe | 59 HA | 65 HA | 47 HA | 63 HA at inner toe/outer heel, 35 HA rest of shoe |
| Heel Tab Type | None | Finger loop | None | None | Finger loop |
| Width Options | Regular, wide | Regular | Regular | Narrow, medium, wide, extra wide | Regular, wide |
| Heel Compression Stiffness | 48 lbf | 44 lbf | 35 lbf | 52 lbf | 40 lbf |
| Toe Compression Stiffness | 51 lbf | 38 lbf | 40 lbf | 56 lbf | 42 lbf |
| Toe Box Volume | 6.4 in^3 | 6.2 in^3 | 6.7 in^3 | 6.5 in^3 | 6.7 in^3 |
| Rocker Angle | 24.0 deg | 22.0 deg | 12.5 deg | 26.5 deg | 26.0 deg |
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Our Analysis and Test Results
The Glycerin 21 was released with an additional 2mm of DNA Loft v3 midsole cushioning, pushing into maximalist runner territory. It lacks the inherent comfort of many maximally padded runners on the market, resulting in a somewhat loose and heavy underfoot feel.
If a reliable, stable, and traditionally-shaped shoe is what you are looking for, the updated Glycerin is likely going to be a good fit for you.
Credit: Ally Arcuri
Landing Comfort and Cushioning
With a heel that stands tall at 28mm and a front stack of 18mm, the updated Glycerin boasts an additional 2mm layer of DNA Loft v3 foam in its midsole for added comfort. However, the Glycerin rides like Brooks may have gone a tad overboard with their maximalist ambitions. The cushioning is chunky and rather rigid, detracting from its landing comfort and cushioning score. The Glycerin 21 seems to have been designed to keep up with other maximalist trends, but it lacks the delectable comfort and energy return of some of the higher-scoring options. The Glycerin is worth a try if you are in the market for a road running shoe that feels chunky and protective underfoot. Compared to its predecessors, all of which have softer but less midfoot loft, this version dropped the ball on landing comfort.
With an additional 2mm of underfoot cushion, the newest Glycerin provides more protection than previous versions.
Credit: Ally Arcuri
Responsiveness
Brooks took a shoe that has had varying levels of responsiveness over the years and made it into a real clod-hopper. We would venture to assume that no one is hitting their top speeds in the updated Glycerin - we certainly aren't. The width of the platform on the Glycerin is notable, and the toebox feels almost slappy, inhibiting any bouncy energy return. The Glycerin is not the worst for a rigid and protective walk-jog experience, but we have quite a few other recommendations for runners who want a responsive road running shoe.
While this version of the Glycerin doesn't have the level of responsiveness that we recommend in a racing shoe, it is comfortable and reliable enough to get the job done.
Credit: Natalie Kafader
Stability
Prior models of the Glycerin lacked the lateral stability that Brooks is so skilled at executing but in a neutral and comfortable way. With this version, Brooks leaned into a bit of lateral rigidity to counteract the additional stack. The result is a neutral running shoe with an extra dose of stability. The lateral walls and heel cup are comfortable and firm, providing strong durability and preventing heel slippage. If a true stability shoe is what your heart desires, we struggle to recommend the Glycerin 21 since Brooks has a higher-scoring lineup of stability-focused shoes. If you are in the market for a shoe with some stability with thick and firm cushion that provides some stability, the Glycerin could hit the mark.
Though not marketed as a stability shoe, the Glycerin offers plenty of support for runners who like firm-feeling side walls and heel cups.
Credit: Ally Arcuri
Upper Comfort
We must start by saying that the Glycerin 21 runs hot. Brooks created a new, engineered warp-knit upper, and while it definitely hits the tactile comfort portion of the equation, the weave is tight and lacks breathability. There are pros and cons to consider with a tighter fabric weave. Our testers appreciated that their socks did not feel wet after crossing a grassy field on a few testing runs, but a warm shoe is only sometimes a good choice, especially if you live in a warmer climate or do most of your running on nice days.
The Brooks Glycerin 21 is not as breathable as many other road shoes in our testing. This works well for cold weather runs, but on warmer days the shoes feel stuffy.
Credit: Natalie Kafader
If you are contemplating the Glycerin, think first about the running conditions your local climate offers. If you experience cold winters and want a beefier shoe to keep you cozy outside, this is a great place to start looking. Superficially, the weave of the upper feels comfortable. The toe box is on the wider side, and a wide version is available, making the Glycerin suitable for runners who enjoy the extra real estate.
The plush tongue provides an extra does of comfort, but the thicker weave decreases this shoe's breathability.
Credit: Ally Arcuri
Weight
The additional cushion on this new version of the Glycerin adds a clunky underfoot feel that we are not especially fond of. The chunkiness of the heel and 10mm drop make this shoe feel heavier and more imbalanced than most, making its actual weight almost irrelevant. Each women's size 6.5 shoe weighs 7.86 ounces, allowing it to sit comfortably in the middle of the pack. The heel of the Glycerin rides thick and wide, making this shoe feel heavier than it is.
Each women's size 6.5 weighs in under 8 ounces, but its weigh distribution doesn't feel svelte or agile.
Credit: Natalie Kafader
Should You Buy the Brooks Glycerin 21?
In the past, we have wholeheartedly recommended the Glycerin, but this iteration gives us pause. That is not to say that it is a terrible shoe across the board, but it has some unique features that won't be universally appealing. Better stability options exist, as do better highly-cushioned options. If you are a diehard Glycerin fan, be prepared for a departure from the norm. If you love the shape and fit of traditional Brooks running shoes, you might like the Glycerin after all.
While not our favorite shoe this time around, it has plenty of qualities that might make it a worthy contender when you decide to purchase your next road running BFF.
Credit: Ally Arcuri
What Other Running Shoes Should You Consider?
If you are looking for an alternative to the Glycerin 21, the most obvious recommendation is the high scoring Brooks Adrenaline 23. With built-in GuideRails, the Adrenaline rides like a traditional and stable running shoe should. Equipped with correcting architecture for overpronators, the Adrenaline is our go-to recommendation for support-seeking runners. If you like the idea of a well-cushioned shoe, we encourage you to check out one of our current favorites, the responsive and plush Asics Novablast 4. With 40mm of soft underfoot cushion and a bouncy energy return, the Novablast is the shoe that has it all.
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Ally Arcuri
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