Brooks Glycerin GTS 23 Review
By Matt Klein and Bach Pham
Brooks Glycerin GTS 23Price: $169.95 at Running Warehouse
Weight: 10.8 oz, 306 g (men's size 9), 9.8 oz, 277 g (women's size 8)
Stack Height: 38 mm heel / 28 mm forefoot (Other Sources: 38/30)
Drop: 10 mm (Other Sources: 8 mm)
Shoe Purpose: Max cushion, moderate stability trainer
Pros: Centered ride, great for walking, somewhat rolling ride
Cons: Firm midsole, overly controlling GuideRails, heavy
RUNNING SHOE SUMMARY
The Brooks Glycerin GTS 23 is a max cushion stability trainer. The GTS series uses GuideRails to provide guidance-based stability. The latest edition continues Brooks' move to push all footwear in their lineup from 12mm to 10mm. The Glycerin as a result gets a little more DNA Tuned midsole in the forefoot this year. The shoe features a firm, but cushioned and responsive ride that is best for easy paces but can move a little bit uptempo. While the changes make the Glycerin and Adrenaline GTS similar in stack height, the DNA Tuned midsole offers a more premium underfoot experience all-around in the Glycerin compared to the Adrenaline.
SIMILAR SHOES: Hoka Gaviota
PAST MODEL: Brooks Glycerin GTS 22
FIT
(To learn how a shoe should fit, check out our full podcast on fit by Matt Klein.)
Matt: The Brooks Glycerin GTS 23 fits me slightly short in my US men's 10. There is a decent amount of pressure at the end of my toes, so those between sizes should consider going up a half size. The engineered triple jacquard knit fits normal to slightly wider, but the toe guard causes the toe box to feel more tapered and slightly short. The forefoot is slightly wide with a normal volume. This continues into a normal to slightly snug midfoot due to a massively thick and non-gusseted tongue. The tongue reduces the amount of space in the midfoot and while it does create a little pressure on the top of the foot, it easily protects the foot from the laces. Fortunately, the laces do not need to be tightened much to get a secure fit. However, the tongue occasionally slips when turning, so it needs to be centered every time you put on the shoe.
The heel fits normally but is secured by a large amount of heel collar padding around the top. There is an extremely stiff heel counter in the rearfoot with padding only at the top of the heel. This exposes the bottom part of the counter, which is noticeable. Those with sensitive heels (Haglund deformities) will not do well with the Glycerin GTS 23. The amount of padding in this shoe helps with security and I have not had any sliding issues. The inner liner is quite comfortable and those with the right size may find they can run sockless in them. For me, the shoe is slightly too short and the toe guard presses against my toes, so I have needed to use socks.
Typical Size: Men's US Size 10
Shoes that have fit Matt well: On Cloudboom Strike, Asics Gel-Nimbus 27, Xero HFS, Topo Cyclone 3, Adidas Adizero Evo SL
Shoes that have fit snug: Hoka Arahi 7, Brooks Launch 11, Diadora Mythos Vigore 3
Shoes that have fit large: Salomon S/Lab Phantasm 2, Adidas Agravic Speed Ultra
Bach: The Brooks Glycerin GTS 23 is decent in length and volume for me, but features a toebox that causes some light rubbing around the side of my big toe. The upper also functionally needs a little break-in. I was concerned on my first run that I wouldn't be able to run in the shoe at all due to a lack of structure that was pushing me slightly medially, but after the first run it settled and kept my foot a little more centered on the platform and since has only improved. I would still say that the medial side is a touch off as a whole which doesn't ruin the ride, but limit my usage of the shoe to regular daily mileage at most.
The heel fit was secure for me and the shoe was easy to lace up without any issues. I found the breathability to be relatively okay as well. The tongue did not provide any issues for me on my end.
Typical Size: Men's US Size 9.5
Shoes that have fit Bach well:
Nike Pegasus 40, Saucony Guide 17, Mizuno Wave Inspire 19, Saucony
Endorphin Speed 3, Nike Structure 25
Shoes that have fit snug: Hoka Arahi 7, Asics Kayano 30, Puma Electrify Nitro, Brooks Hyperion, Hoka Clifton 9 GTX
Shoes that have fit large: Hoka Gaviota 5, Reebok Floatride Energy X
Doctors of Running Checklist
Is This a Good Shoe for Walking: Yes
Is This a Good Shoe for Standing: Yes
Is the Forefoot Flexible: Mildly Flexible
How Flexible is the Shoe: Not Flexible
Is This a Good Heel Bevel: Somewhat
Recommended for Haglunds: No
Is This Shoe Orthotic Friendly: No
Recommended for Sockless: Somewhat
Durability Expectation: Above Average
PERFORMANCE
Matt: The Brooks Glycerin GTS 23 is a daily training shoe. It features a full-length DNA-tuned midsole (nitrogen infused EVA) that, like the Glycerin Max 2, is surprisingly firm but cushioned. The cushioning can best be described as "dense." This feels softer while walking but firms up while running. The forefoot is slightly firmer than the rearfoot, supposedly because of larger "cells" in the rearfoot and smaller ones in the forefoot. The GuideRails and posting add a large amount of firmness to the underfoot feel, but the foam also takes time to break in. My first run felt harsh underfoot, and it has taken almost 30 miles for the midsole to break in a little. There is now an 8mm drop thanks to an additional 2mm of foam in the forefoot. Per Brooks it is still a 10mm drop, but other sources have suggested it to be lower. It feels closer to 8mm to me. The now moderate drop helps smooth out the heel transition. There is a bevel in the rearfoot that is fairly sharp and clunky early on. As it breaks in and the foam compresses more, this starts to smooth out. The forefoot is somewhat smooth thanks to a large forefoot rocker and mild flexibility. This transitions much better than the rearfoot and only improves as time goes on. It is not stiff enough for those with toe mobility deficits, so at least mild toe flexibility is needed.
Purpose-wise, the Glycerin GTS 23 only works for easy runs. The weight increase is noticeable and the ride is not fast or responsive. My size 10 weighs 11.6 ounces, making the Glycerin GTS 23 one of the heavier shoes I have tested recently. Picking up the pace feels awful and these are best for easy running or walking efforts. Those who want a firmer/dense and cushioned ride may be able to use these for long runs, but I have found them far too firm to want to use them beyond short to moderate distances. Traction-wise, I have found these to do fine on dry road a mild dirt. The ribbed outsole seems to do fine on smooth dirt but I would consider a trail shoe for more technical terrain. On wet road this shoe is fine and I have not had any slipping issues. Durability-wise the outsole and midsole are doing well. The midsole is firm enough there doesn't seem to be much to break down and the outsole only has a tiny bit of wear after 30 miles. So I expect an above-average number of miles out of these shoes.
Bach: The big difference with the Adrenaline and Glycerin GTS is the DNA Tuned midsole which offers what feels like an airer experience (despite being the same weight) that is cushioned and dense (see Guide 19) and also is fairly firm. The firmness does offer what feels like some mild versatility to the shoe and some light responsiveness that makes the shoe feel less muddy than the Adrenaline. I run more midfoot forward and felt the transitions were okay - not super smooth, but not terribly clunky either. The rocker helps get you moving decently.
The GuideRails, however, create a slightly awkward experience for me. I have one foot that is more stable than the other, and my leg that typically needs a little more help in stability felt like it was resisting the Guide Rails a bit. I generally want to let any pronation I have happen and just have a stable underfoot that helps support the foot, but the guidance instead kind of fights my feet. This causes some irritation on the run for me, particularly in my shin. My neutral leg had no issues with the Guide Rails. Between the slightly rubbing and the guidance, I found the shoe to be limited to very easy paces where the stability component is more tapered. The ride has overall continually improved with miles becoming easier and easier, but the combination of issues I have still remain a problem.
The shoe does okay on mildly wet terrain and they do okay on mild gravel and dirt roads. There is a ton of outsole which additionally firms up the ride. The outsole should last for tons and tons of miles.
STABILITY
(Learn more about stability in our full guide)
Matt: The Brooks Glycerin GTS 23 is a moderate stability/guidance shoe. There are mild sidewalls in this shoe and a wider base but the GuideRails, particularly the medial one that acts like a medial post, are the most significant forms of stability. Unlike prior versions, the medial GuideRail is not as post-like. Instead the GuideRails seem to provide noticeable control throughout the length of the shoe. I believe this is what contributes to the stiffer ride as it feels like my foot is being forced into the middle of the shoe. This is not necessarily a bad thing and will work well for those who do not do well with traditional posting. For me, it feels like it is too controlling, almost reminiscent of recent models of the Brooks Beast. I have had some anterior tibia and midfoot discomfort running in this shoe, which I generally experience in shoes that are too controlling. With the medial post feeling a bit mild, the Glycerin GTS 23 feels more like an aggressive/higher level guidance shoe. This is noticeable throughout the length of the shoe but most specifically in the rearfoot and midfoot. Those who want this will do well, while others may notice some aches and discomfort as they are pushed outside their normal preferred movement pathway.
Bach: The Glycerin GTS 23 is a lot of built-in stability. There are the GuideRails which moreso than in recent models provide a lot of guidance. There is a real attempt to shift the foot very centered, and as mentioned earlier this kind of fought with my foot which didn't like being corrected. There are also the modern elements of big sidewalls for added guidance, a wide base, and the firm sole that make this a fairly high level of stability.
Guidance and I are often hit and miss. Milder versions of the GuideRails like in the Launch GTS (RIP) or models that are really built to run slow like the Brooks Beast have been excellent, while models like this GTS 23 or past versions of the Hoka Arahi with the J-Frame have always been a struggle. Many folks will get along okay with this level of control, but others may like a more natural stability built in. That is just something to consider with the Glycerin GTS 23, which is probably one of the highest level of stability motion control shoes available right now.
Thoughts as a DPT: Guidance vs Control
By Matthew Klein
Brooks has been using their "GuideRail" system for a long time. While it came into the public's attention more with its use in the Adrenaline 19, it was first used in the Brooks Transcend. The Transcend was a replacement for the Trance series, the long-standing highly cushioned, premium stability shoe of the Brooks lineup. This would eventually become the Glycerin GTS years later. The GuideRail technology has always been touted as a more holistic approach to stability. Rather than a single medial post that was common for years, the GuideRail works similarly to bowling "bumpers" on both sides of the foot. One on the posterior lateral side of the heel into the midfoot to reduce excessive supination during heel strike into midstance, while the other sits in the medial side of the heel/midfoot to reduce excessive pronation during the same phases. The GuideRails are only supposed to "engage" when you roll too far in one direction, supposedly making GuideRails suitable for neutral runners as well as those that need stability/guidance.
Prior versions have still felt like they still have a medial post, which has felt great as a stability wearer. The current version has less of a post feeling but a more stiff and rigid underfoot feel. I have had both midfoot and shin pain from wearing these that I think is due to stiffening and deepening the GuideRails. The GTS version feels completely different in the rearfoot and midfoot compared to the non-GTS version, which feels smoother, lighter and softer. Adding stiffness and rigidity to a shoe can certainly make it more stable, but there is a point where it becomes uncomfortable rather than providing guidance. A stiff, rigid shoe can start to feel more controlling, completely stopping motion rather than facilitating it. This may also be due to the midsole compressing less due to its increased firmness, which can make an already firmer part of the shoe feel even more so. It is likely the combination of the firmer/less compliant midsole with deeper GuideRails that make the Glycerin GTS 23 feel more like a motion control shoe rather than a moderate, smooth stability shoe. This starts to encroach on the Brooks Beast/Ariel's territory, which is not necessarily a bad thing given the complete loss of motion control shoes in the last few years. If the Brooks Glycerin GTS is taking over the place of the Addition series, meant as a lighter, less pronounced Beast/Ariel, it needs to lean into that. If not, I would soften that midsole to balance out guidance rather than control.
RECOMMENDATIONS
Matt: I am honestly disappointed in this update. The shoe is heavier, the midsole is far firmer and the fit is back to being slightly off. I do appreciate that there is less posterior flare than previous versions and the heel does smooth out after some runs. However, the midsole is reminiscent of the Glycerin Max 2's DNA Tuned which is far too firm for a shoe with this much underfoot and this high a cost. While a softer midsole does inherently decrease stability, it would be helpful here to balance out what I consider to be a design that is too controlling. This shoe's stiffness/firmness gets in the way of letting the foot do what it does naturally while providing a solid amount of forward guidance. The goal should not be to force the foot to do things, but guide it forward. I believe the firmness tips the scales toward forcing. Brooks has plenty of technology to create a lighter, softer, and more stable shoe, which was what the Glycerin GTS 21 was. So I still have faith they can pull this off.
Bach: This was a conflicting update for me. The midsole isn't entirely bad as it gets broken in. I like a firmer sole and could feel the shoe opening up and getting to a place I liked by the end of my testing miles (20). The upper, however, can definitely be improved to reduce rubbing in the forefoot and to keep the foot more centered on the platform in general. The other area to explore is the integration of the GuideRails. I do think it is pretty intensely tuned here, especially having enjoyed and done well in the recent Beast which caused no issues for me. I believe this model should really focus on the premium midsole and ride aspects and kind of dial back on the motion control to help accommodate more runners. The Beast remains a viable option for high stability needs, but I think to have that premium option to the Adrenaline, it makes the most sense to be ride-focused rather than stability-oriented.
WHO IS THIS SHOE FOR?
Matt: The Brooks Glycerin GTS 23 is a moderate to high level stability/guidance shoe for those who want a firmer but stable ride in a heavier shoe for daily training and walking. The fit will work best for those who want a slightly wider forefoot and a heavily padded midfoot/heel. Those between sizes will need to go up a half size. The midsole will work best for those who want a firmer, stable ride with a moderate drop. The stability will work for those who don't necessarily want to be pushed medially/laterally but want to be kept firmly in the middle. I am continually confused by the most recent iteration of the DNA tune for running, but for walking it makes complete sense. I notice more of the cushioning during slower general movement when my loading rates are low. So as a stable, centered walking shoe this may be a great option and I have seen a ton more people wearing Glycerin GTSs for walking recently. The durability seems to hold up well and helps this shoe compete well for walkers among other premium shoes like the Kayano or Structure Plus. For running, I would reconsider tuning this a bit differently.
Bach: The Brooks Glycerin GTS 23 is a premium training shoe for those with a strong preference for guidance-based stability. The shoe feels best for very easy running and if the fit works, long-distance walking. For walking, the guidance is far less noticeable for the most part and for me, besides the rubbing issues, is very comfortable. For running, there are a lot of options that carry a lot of similarities to the Glycerin GTS, both with and without guidance, that I would likely take over the Glycerin GTS right now.
GRADES
Matt
Fit: B (Fits a half size short but upper is secure despite a mildly loose but thick tongue. Tons of padding)
Performance: C+ (Heavy, slowshoe that is firm/clunky that is far better for walking than running)
Stability: B+ [Moderate/High Guidance] (Highly centered, borderline controlling ride)
Value: B- (Premium features are there but the ride and weight don't put it ahead of other models on the market)
Personal: C- (I had high hopes but the firm midsole is clunky, heavy and has caused me consistent discomfort while running)
Overall Design: B-
Bach
Fit: C+ (Rubbing around toe and early break-in issues)
Performance: B- (I think the ride has gotten better with miles, but there is a break-in which some may not like and the integration of GuideRails may challenge many)
Stability: B+ (A ton of stability, but may be too controlled for some)
Value: B (Plenty of durability for ages, but dependent on how the rest of the shoe works with your mechanics)
Personal: C (If the rubbing and issues with GuideRails weren't an issue, I honestly would love this one a lot, but the two are hard to overcome)
Overall Design: B-
SHOP | SUPPORT DORBrokos Glycerin GTS 23Price: $169.95 at Running Warehouse
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FURTHER READING
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