Physical Therapists Using Clinical Analysis To Discuss The Art And Science Behind Running and The Stuff We Put On Our Feet

Post Page Advertisement [Top]

Brooks Glycerin 21 Review
By David Salas

The Brooks Glycerin series receives a new DNA Loft V3 midsole aimed at creating a more plush and comfortable experience. The upper has also been altered to allow for a more streamlined fit without sacrificing the plush nature of the shoe and breathability. The Glycerin is the premium neutral trainer for the company. It also features a counterpart in the Glycerin GTS 21, which is the premium stability trainer of the duo.

For Matt's Brooks Glycerin GTS 21 Review, visit Page 2

Brooks Glycerin 21
Price: $159.95 at Running Warehouse
Weight: 9.8 oz, 277g (men's size 9), 8.8 oz, 249 g  (women's size 8)
Stack Height: 38 mm / 28 mm
Drop: 10 mm
Shoe Purpose: Premium Cushioned Daily Trainer

Pros: Durable workhorse, comfortable for both walking and running
Cons: Not very responsive, less exciting materials compared to similar pricepoint


The Brooks Glycerin 21 is a continuation to the premium trainer line. The shoe features a new midsole (DNA Loft V3) for increased softness and cushioning. The upper has also been re-worked to give a more streamlined experience. This is a workhorse training shoe to log high amounts of miles in. 

: Mizuno Wave Sky 6, Puma Magnify Nitro 2
PAST MODEL: Brooks Glycerin 20

(To learn how a shoe should fit, check out our full podcast on fit by Matt Klein.)

The Brooks Glycerin 21 fits true to size in my Men's 9.5. The lockdown of the shoe is pretty good and the width should be accommodating for most. The heel width is normal, the midfoot normal to slightly wide, and the forefoot wide. There is a good amount of volume to the shoe without making your foot feel like it is swimming or that the lockdown is sloppy. The mesh material of the upper feels pretty plush throughout without sacrificing breathability. It is a little on the warmer end, but not so much I cannot run a long run in it. There is a heel counter that is padded and integrated well with the heel collar. The tongue is padded and allows for a good lockdown from the laces without irritation. The length of the shoe may be a tad bit long, but otherwise really good. I do think I'd like the upper a tad more breathable, but it is not bad in its current state. On the medial and lateral side of the forefoot there is a small sidewall from the midsole. I did get a little bit of rubbing on the medial portion that gave me a small blister. Granted this is following a 17 mile run, but still. I think widening the platform there, or cleaning up that interface could be a little better. I'm splitting hairs here though, this is a solid upper and fit. 

David's Typical Size: Men's US Size 9.5
Shoes that have fit David well: Nike Vomero 17, Saucony Ride 16, Puma Velocity Nitro 3

Shoes that have fit snug: HOKA Arahi 7
Shoes that have fit large: Salomon Aero Glide

Doctors of Running Checklist

Is This a Good Shoe for Walking: Yes
Is This a Good Shoe for Standing: Yes
Is the Forefoot Flexible: Yes
How Flexible is the Shoe: Moderate
Is This a Good Heel Bevel: Yes
Recommended for Haglunds: No
Recommended for Sockless:
Durability Expectation: Above Average


The Brooks Glycerin 21 is a premium neutral training shoe. The shoe fit the bill for most of my expectations. The shoe feels like a more plush Ghost that can tackle daily mileage. The Glycerin 21 did see a foam update with DNA Loft V3, a now nitrogen infused midsole. I will say the foam feels softer than previous Brooks shoes, but still on the firmer side of premium foams. With that said, there is still plenty of foam and cushion for logging big mileage. The ride of the shoe was a little boring, but smooth. The Glycerin 21 feels like a traditional high drop training shoe with a slightly more plush offering. This is not a bad thing though. I actually really appreciated a simple ride that flowed well. The big thing the Glycerin gave me was comfort. The shoe was not very responsive, lightweight, or anything that exciting, but it was consistent, predictable, and smooth for its purpose. I can definitely see someone using this as their mileage workhorse.

For being a higher drop shoe, the heel bevel is actually done really well and the transitions don't feel super choppy. The forefoot has moderate flexibility under load and gives a decently natural feeling toe off. Outsole traction is decent and I did not feel any hesitation with running through runnable trail/grass conditions. The experience was relatively pleasant and comfortable. I was joking with my training partners that this might win "most boring shoe of the year that is actually really good." The boring comment is in the nicest way. This shoe is pretty comfortable. 


The Glycerin 21 is definitely a neutral shoe. There is a lot of foam underfoot and the upper is somewhat spacious with a little stretch. The Glycerin 21 does do some things good though for stability. I am a fan of the sole flaring and sidewalls through the heel and forefoot. I do wish I had less rubbing on the medial forefoot wall, but I appreciate the design. The platform underfoot is also pretty wide. Traction is also quite good for a training shoe. Despite being a very neutral shoe, I would not classify it as unstable either. 



I enjoyed my time in the Glycerin 21. My main recommendation would be for the upper and fit. The upper is comfortable, but does still run on the warmer end. That, combined with some rubbing at the medial forefoot did end up causing a small blister. I think making the platform integration with the upper at that forefoot region would help. I would also like to see Brooks continuing to make efforts towards a more breathable upper in a plush offering. 


The Brooks Glycerin 21 is a daily training shoe for someone looking to have a traditional high drop feel with a tad more plushness. There is plenty of cushioning for daily mileage and long runs. This will best serve as a workhorse trainer, or even daily walking shoe. The ride can come off as uneventful, but it is smooth, predictable, and reliable underfoot. 


Fit: B+ (The dimensions throughout are good, though upper still warm, and I did have some irritation through the medial forefoot sidewall.)
Performance: B+/A- 
(The ride isn't anything exciting but it is smooth for logging miles until the cows come home. Outside of some of the rubbing I could forget they were on my feet. The foam is a tad underwhelming compared to competitors foams.)
Stability: B+ (Very neutral shoe, but wide base, traction, and pretty good lockdown do help.)
Value: B+ (A workhorse that will last for you. Only reason why it is not an A is that it feels behind from a material standpoint compared to the competition at similar price point.)
Personal: A- (Predictable and smooth. A little boring, but I don't need anything that exciting for easy days.)
Overall Design: B+/A- 


Brooks Glycerin 21
Price: $159.95 at Running Warehouse

Shop Men | Shop Women

Page 2:
Brooks Glycerin GTS 21


Facebook: Doctors of Running
Youtube Channel: Doctors of Running
Instagram: @doctorsofrunning
LinkedIn: Doctors of Running
Strava: Doctors of Running
Podcast: Virtual Roundtable
Pinterest: Doctors of Running


Check out the Doctors of Running Podcast to find more reviews, interviews, and running features from the team.

Visit our Podcast Page
Find us on Apple
Find us on Spotify

Editor's Note: As always, the views presented on this website belong to myself or the selected few who contribute to these posts. This website should not and does not serve as a replacement for seeking medical care. If you are currently injured or concerned about an injury, please see your local running physical therapist. If you are in the Los Angeles, Santa Barbara, Danbury and Stevens Point areas, we am currently taking clients for running evaluations.

***Disclaimer: These shoes were provided free of charge in exchange for a review.  We thank the people at Brooks Running for sending us a pair.  This in no way affected the honesty of this review. We systematically put each type of shoe through certain runs prior to review. For trainers and performance trainers, we take them on daily runs, workouts, recovery runs and a long run prior to review (often accumulating anywhere from 20-50 miles in the process). For racing flats we ensure that we have completed intervals, a tempo or steady state run as well as a warm-up and cool down in each pair prior to review. This systematic process is to ensure that we have experience with each shoe in a large variety of conditions to provide expansive and thorough reviews for the public and for companies. Our views are based on our extensive history in the footwear industry and years testing and developing footwear. If you are a footwear rep looking for footwear reviews or consultations on development, we are currently looking to partner with companies to assist, discuss and promote footwear models. Partnership will not affect the honesty of our reviews.

Bottom Ad [Post Page]

// ]]>