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Price history
Our verdict
The Glycerin GTS 21 is Brooks' plush daily training shoe with a layer of gentle support built in. GTS stands for Go To Support, so this is the stability sibling of the neutral Glycerin 21: same soft, high-cushion ride, but with guide rails that quietly hold your stride together when your form starts to wobble. At 289g with a 10mm drop, it is a substantial, protective running shoe rather than a light or fast one. That weight is the price of the cushioning, and it is aimed squarely at runners who value comfort and a bit of guidance over speed. We rate it as a soft-riding stability daily trainer for easy miles, long runs and everyday base training. If you overpronate mildly, want a max-comfort shoe that keeps you aligned, and are not chasing pace, it is one of the easiest shoes in this class to just put on and run.
Key features
- GuideRails supportKeeps your stride aligned with a gentle nudge only when your form drifts, so mild overpronators get help without a harsh medial post
- Soft, high cushioningSoaks up hard pavement and protects tired legs over long runs and daily mileage
- 10mm dropGives a smooth, familiar heel-to-toe roll that suits heel-strikers and easy-pace running
- Roomy, padded upperDelivers a plush, planted fit with space for toes to splay on longer efforts
- Multiple width optionsLets wider or narrower feet find a proper fit instead of settling for one shape
Who it suits
Who should buy it
- Mild overpronators who want gentle support in a soft, comfortable daily trainer
- Heavier runners and heel-strikers who need deep cushioning on hard surfaces
- Runners logging easy miles and long runs who value comfort over speed
- Anyone with wider feet who wants a plush shoe in a true width option
Who should not buy it
- You want a light, responsive shoe for tempo runs or racing
- You have severe overpronation and need firm motion control
- You prefer a firm, ground-connected ride over soft foam
- You are on a tight budget and this £165 shoe is a stretch
Best uses
Extra information
Fit & sizing
The Glycerin GTS 21 fits true to size for most runners, so order your usual Brooks size. The engineered mesh upper has a roomy, rounded toe box that suits medium and slightly wider feet, with enough space for toes to splay on long runs without feeling sloppy. Midfoot lockdown is secure without pinching, and the padded heel collar gives a plush, planted hold that keeps you from slipping at the back. Brooks offers this model in multiple widths (B, D, 2E and 4E on many colourways in the UK), so hunt out a wider option if standard road shoes usually feel tight. If you are between sizes or plan to wear thicker winter socks, we would size up a half. Runners with genuinely narrow feet may find the standard width a touch generous and should cinch the laces firmly.
Performance breakdown
Ride & feel
This is a soft, cushioned, sink-in ride rather than a springy or snappy one. The GTS 21 feels planted and protective underfoot, soaking up hard pavement and taking the sting out of long efforts. Roll along at an easy or steady pace and it is genuinely comfortable, with a smooth heel-to-toe transition helped by the 10mm drop. Push the pace and the shoe shows its limits: at 289g it is not built to turn over quickly, and the soft foam does not give much back when you ask for pop. That is fine, because that is not its job. Think of it as a comfort-first cruiser for the miles where you just want your legs looked after, not a shoe you reach for on tempo day.
Cushioning
Cushioning is the whole point here, and the Glycerin GTS 21 delivers a deep, forgiving stack that leans soft. There is plenty of foam under both heel and forefoot, so heavier runners and heel-strikers get real protection on hard surfaces and repeat long runs. The softness is on the plush end of the daily-trainer scale, which is exactly what makes it so easy on tired legs late in a run. The trade-off is a slightly muted, less connected feel for the ground, and it can feel a little dead if you like a firmer, more responsive platform. For soaking up impact over 10, 15 or 20 miles, though, it is one of the more comfortable shoes in its bracket.
Stability
The GTS support here is subtle and structural rather than corrective. Instead of a hard medial post, Brooks runs guide rails along the sides of the heel that only engage when your stride drifts too far inward, so a neutral runner barely notices them while a mild overpronator gets a gentle nudge back into line. It is a supportive-but-soft approach, closer to the guided feel of the Gel Kayano 32 than to an old-school firm stability shoe. That makes it a good pick if you want a little insurance for tired late-run form without a rigid, over-controlling platform. If you have severe overpronation or need aggressive motion control, this gentle guidance may not be enough on its own.
Upper & comfort
The engineered mesh upper is comfortable and well padded, with a soft internal lining that feels good against bare skin and forgives sockless mistakes on short outings. The tongue and heel collar are generously cushioned, adding to the pampered, slipper-like feel that is the whole point of the Glycerin line. Breathability is fine for UK conditions across all seasons, though on hot summer runs the plush build runs a touch warm compared with a thinner racing upper. Structure and hold are good for a comfort shoe, and there are no obvious hot spots or seams to break in. It is a durable, everyday upper built to survive months of daily mileage.
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FAQ
Specifications
| Category | Stability |
| Surface | Road |
| Drop | 10mm |
| Heel Stack | 38mm |
| Forefoot Stack | 28mm |
| Weight | 289g |
| Carbon Plated | No |
| Stability | No |