6 March 2024
Shoe Review: Brooks Glycerin 21

Travis spent a couple of weeks testing out the Brooks Glycerin 21, their premium neutral running shoe. The Glycerin 21 is designed for longer runs, by providing a cushioned and responsive feel underfoot. 

Prefer to watch a video instead? Take a look at our YouTube shoe review!!


The specs:

Weight: 286g (mens U9S) 258g (womens US8)
Stack height: 28mm (heel), 18mm (forefoot)
Heel to toe drop: 10mm
Midsole: DNA Loft V3 – Nitrogen infused 

Similar Models:
Ascis Nimbus, Mizuno Wave rider, New Balance 1080, Saucony Triumph

Travis was lucky enough to spent a couple of weeks trying out the Brooks Glycerin 21 and Glycerin GTS 21. We trialled them for a few runs to see how they compared to our usual shoes. I was able to enlist the help of a good friend and runner Hugh to help with the testing of these shoes.

I tested the Glycerin 21 which is the ‘neutral’ version of the shoe. These shoes are designed to provide comfort and reduce the stress of running on the body. Hugh tested the Glycerin GTS (Go To Support) 21 which is the more structured version, (you can check out his thoughts on the GTS here). The GTS has the same cushioning as the neutral version, however it has the addition of Brooks guide rail technology, which helps guide the foot during the gait cycle.

My first impression of the Brooks Glycerin 21 was very positive, as they have a very roomy toe box compared to most conventional running shoes.

What does the shoe feel like to run in?

During the time I tested the Brooks Glycerin 21, I was able to get in around 27km in the shoe – a 10km run and a longer 17km run, both with an average pace of 5:40min/km. The conditions for each run were very different; the 10km was done in the rain and the 17km was done in dry conditions which gave a nice contrast of how the shoe handled both conditions.


The fit of the shoe was great. I wear minimalist/barefoot shoes on a daily basis, so I am quite used to wearing shoes with a lot of space in the toe box. On initial wear, I wasn’t frustrated by the toe box of the Glycerin. I experienced no rubbing or excessive pressure during my runs. The knit upper is quite padded and locked down really well, but didn’t feel constricted which I liked as I didn’t feel like my toes were being crushed for the entire run. 

Feel (performance):

Something I found interesting with these shoes on my first run was how responsive they were underfoot especially in very wet conditions. The midsole was accommodating at contact with a soft but stable compression. I never felt like I was stuck in the shoe trying to get through the middle of my stride, but instead felt like the shoe was helping to get me through faster, as when I hit my toe off position I was being pushed out of the ground. This feeling stayed throughout the distance. As I hit the last 5km of my long run, I was expecting that the responsiveness would diminish but this was not the case, it helped up really well and made for a really enjoyable ride for the duration of the run.

In terms of stability, I found that even in the wet the Glycerin was a very stable ride and I never felt at any point like I was going to slide off the midsole or lose traction at initial contact. I was pleasantly surprised at how much grip I did have running through puddles and then followed by some unhill sections of my run. I felt secure both up and down hills and also didn’t feel like the traction was so excessive that you hit the ground and come to an abrupt stop. Overall it was great in any condition and I wouldn’t worry about extreme weather and slippage with the Glycerin 21. 

Final thoughts:

Overall I was very impressed with this shoe, and was surprised how it felt for me being a higher heel drop at 10mm compared with my current rotation which ranges from 0-4mm drop. The Glycerin 21 would be a nice addition to the rotation if you regularly use a lower drop, as a shoe that can be used in some of the longer runs, or as a shoe when you want to take a bit of load off the calf muscles. 

The Glycerin 21 is a really nice shoe choice if you’re looking for something to do a bit of everything in with your running training. Although it’s designed as a daily trainer for your long runs, I did play with picking up pace in my shorter runs to see how the shoe would feel transitioning up and down. It was really responsive and although not specifically a tempo shoe, if you were just starting out with speed work you could still use the Glycerin 21 quite comfortably whilst you build your shoe rotation.

Is this shoe going to work for me and why might I use it?

No shoe is going to work for everyone. Every shoe is a tool, and you need to know when to use it. 

    • The Glycerin 21 will work well if you are looking for a daily trainer that has a plush, yet moderately firm midsole, with some snappy responsiveness through push off,  this shoe will work well for you. 
    • If you have found in the past that you really struggle fitting your foot in most conventioanl running shoes due to the width around the toes then the Glycerin 21 is a great shoe to check out, as it is wide even in it’s standard width. If you require greater width than the standard, the Glycerin 21 comes in a wide fitting option (2e).
    • Finally, Brooks have also released the Glycerin in a stealth fit, which features a sock like upper. If you want a shoe that you can tie once and then just slide your foot in and go for a run this would definitely be something to check out.