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Brooks Glycerin 20 Review: Lofty Expectations
By Chief Editor/Founder Matthew Klein

There are a few shoes that quickly come to mind when talking about premium daily trainers. The Saucony Triumph, Asics Nimbus and the Brooks Glycerin continue to be standouts. All three have or are about to enter into their 20th iteration, which is a major milestone with how quickly shoes seem to come and go now. Central to many shoes these days, even these premium trainers are seeing the additions of new foams, redesigns and lighter weights. The Brooks Glycerin 20 is no exception with the introduction of the new DNA Loft v3 foam and four total versions with a variety of uppers or stability levels (we also reviewed the Brooks Glycerin GTS 20, the stability version HERE). As the lightest Glycerin to date, version 20 maintains its function as a highly cushioned, premium shoe for daily miles. How soft it actually is compared to how it is advertised is another discussion. 

Price: $159.95 at Running Warehouse
Weight: 10.1 oz, 287g (men's size 9), 9.1 oz, 258g (women's size 8)
Stack Height: Not Provided
Drop: 10mm 
Classification: Premium Daily Trainer


The Brook Glycerin 20 is a premium daily trainer with a softer nitrogen infused midsole. Full length DNA Loft v3 sits underfoot, providing a moderately soft ride for easy miles. A new, cushioned upper provides a normal to fit that with a little stretch. The changes make for the lightest Glycerin ever, with a smooth forefoot transition, but a slightly clunky heel. Best for easy and long miles, the Glycerin 20 is about comfort for those who want a traditional ride from a newer midsole.


The Brooks Glycerin 20 fits me slightly short in my normal men's size 10. While the width throughout is normal, the toe box tapers quickly. This makes for a shorter fit. The upper mesh in the midfoot and forefoot does have some flexibility, but runs warm due to being thicker than average. This increases as you move toward the rear of the shoe. The rearfoot is highly padded with a large amount of heel collar cushioning. There is a stiff heel counter, but I did not notice it due to how much padding there is. The heel counter did become more apparent as the padding flattened with more miles, so those sensitive to heel counters may do well initially but not in the long term.

The upper is fairly flexible but is secure thanks to strategically placed overlays (ie a Brooks logo on the medial and lateral sides of the midfoot). This creates a decent lockdown without being stiff and I did not have to lock down the laces. The tongue is thick and free floating outside of some connection from the laces. I did have some slippage both directions during longer miles, so the laces in the midfoot need to be locked down and the tongue needs to be adequately placed while putting the shoes on.

With the exception of some tongue movement, the Brooks Glycerin 20 has an extremely comfortable inner liner that has worked for me while running sockless. There are only some seems in the midfoot upper transition between the midfoot and heel. These did not bother me and I ran 7 miles without blisters. Thus, sockless running is an option (but make sure you are used to this prior).

Overall, the Brooks Glycerin 20 has a thicker upper that provides a solid lockdown, but those interested should be cautious of it being on the warm side and the strongly tapered toebox. Those sensitive to tapers should consider a half size up.


The Brooks Glycerin 20 has a full length DNA Loft v3 midsole. This is advertised as a soft and bouncy midsole, but really just feels moderately soft. The foam does not rebound well. Howeever, the new 10.1 oz weight (lightest Glycerin ever) does make it feel easy on the legs. Despite the lighter weight, the lack of foam rebound makes this shoe work best for easy mileage and recovery runs where pace is not a concern. While there is a small bevel in the rearfoot, this does not offset the large amount of posterior flare. This makes for an early landing with heel striking and creates a clunky rearfoot. The forefoot has some flexibility and a decent rocker, which makes for a comfortable transition through the front. Those who land farther forward will find the ride better in this version. There is a 10mm drop listed, but this feels higher while running due to the posterior flare if you are heel striking. For those that land farther forward, it feels like a 10mm drop shoe. In line with this shoe feeling more traditional in regards to drop and ride, the outsole is incredibly durable. I have 30 miles in my pair and have not made a dent in the outsole. The midsole has remained consistent and has gotten softer or firmer with more miles. Thus, those wanting an extremely durable, moderately soft (but not bouncy), highly cushioned shoe with a solid forefoot transition will do well in the Glycerin 20. Those who land rearfoot will find this on the uncomfortable side.


The Brooks Glycerin 20 is a neutral shoe without any traditional methods of stability. While there is a posterior lateral bevel, the posterior flare creates an early initial contact and pitches me quickly inward during landings. The sole is wider, and the midfoot does not narrow too much. This does creates a slightly more stable platform inherently, but it is offset by the softer midsole. The sole flare in the forefoot, decent flexibility and anterior rocker create a solid and mildly stable forefoot transition. The softer sole and posterior flare make for a highly neutral ride. While this shoe is not unstable, it isn't decently stable either. Thus, those sensitive to stability - ie, neutral runners - will do well here. 


Those interested in my thoughts on the posterior heel flare should read the Thoughts as a DPT in the Brooks Glycerin GTS 20 Review.

I have talked about tapered toe boxes before, but was is most interesting to me about the Glycerin is the placement of the outsole material and how it affects the flex points in the sole. While most people focus on plates in regards to sole stiffness, that is only one method that can change longitudinal bending stiffness. The thickness and stiffness of the outsole can also directly impact how stiff a shoe feels and the flexibility of the sole. In the case of the Brooks Glycerin 20, I have noticed that as the miles have increase, I've felt the shoe beginning to bend in the midfoot. I began to realize that because the forefoot has thicker and more outsole coverage than the midfoot, the softer sole is bending more right at the transition between the medial outsole coverage at the midfoot and the full width coverage of the midfoot. Essentially, the shoe is bending at the point of least resistance. This is was something that was not apparent in the Glycerin GTS, likely because the medial post adds stiffness in the midfoot the normal Glycerin is missing. Those with midfoot issues should therefore be cautious with this shoe.

That also makes me think that going a half size up in this shoe may be a better idea as the flex point will move farther forward (more in line with the metatarsophalangeal joints) and that will also address the tapered toe box issue. 


The Brooks Glycerin 20 almost got everything right. There is potential here, but the posterior flare and tapered toe box prevent it from as good as it good. The DNA Loft v3 is not as soft as I was expecting and not bouncy at all. If it were softer, Brooks may have gotten away with the posterior heel flare as the midsole would compress fast enough. Unfortunately this is not the case, so the heel just feels clunky and uncomfortable. Like the Glycerin GTS 20, the Glycerin 20 needs to have the posterior flare decreased or a larger heel bevel. The bevel is in the correct place, but it is negated by the extended midsole.

The tapered toe cramps my toes more than I expected. Most shoes recently have done a decent job of not doing this, so this was a surprise to experience again. Toe alignment is fairly important for appropriate transverse plane motion at the metatarsophalangeal joints for shock absorption at the forefoot. Additional, having my toes jammed together is not comfortable. The forefoot has just enough room, so if the toebox could be more anatomic without being sloppy, this would easily fix the front. 


The Brooks Glycerin 20 is a premium, moderately soft trainer for those who want a medium fit, can handle a tapered toe box and who land farther forward. The DNA Loft v3 is cushioned, but not bouncy. The new foam is moderately soft and feels best as a recovery and easy run shoe. The posterior flare at the rearfoot makes for a clunky ride at the back, so those that land farther forward will do better. The upper fits normal and is comfortable, except for a highly tapered toe box. Combined with a flex point in the anterior midfoot, those interested in this shoe may want to consider a half size up. The Glycerin 20 is an interesting shoe with potential, but there is a great deal of work that needs to be done to get it where it can be. 


Fit: B/B- (Warm but comfortable upper made to feel short due to highly tapered toe box, may want to go up a half size)
B/B- (Moderately soft foam, not bouncy with clunky rearfoot and good forefoot transition)
Stability: B [Neutral] (Wider sole, but posterior flare causes abrupt transition inward)
DPT/Footwear Science: B-/C+ (DNA Loft v3 is behind current foam development from other companies. Not responsive or as cushioned as it could be. Outsole coverage creates anterior midfoot flex point. Posterior heel flare creates clunky ride and early initial contact at rearfoot that is not compensated for well enough from the foam. There is potential here, but things need to change in version 21)
Personal: C+/B- (A shoe with a great deal of potential. Tapered toe box, clunky heel, not bouncy foam makes for a shoe I'm not going to keep reaching for)
Overall: B-


Price: $159.95 at Running Warehouse  
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***Disclaimer: These shoes were provided free of charge in exchange for a review.  We thank the people at Running Warehouse and 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.

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