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Tested using Methodology v0.10
Updated Apr 08, 2026 01:43 PM
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Amazon
Tested using Methodology v0.10
Updated Apr 27, 2026 06:21 PM
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Amazon
Weight
262.7 g (9.26 oz)
Heel-To-Toe Drop
10.9 mm
Plate
None
Weight
299.4 g (10.56 oz)
Heel-To-Toe Drop
9.6 mm
Plate
None
Our Verdict
Brooks Glycerin Flex
Brooks Glycerin 23
The Brooks Glycerin 23 and Brooks Glycerin Flex share a name and the same DNA Tuned foam, but have very different ride profiles. The Glycerin 23 is a rather orthodox cushioned daily trainer with a smooth and predictable ride. The Glycerin Flex has a deep groove in its midsole and articulated foam pods that allow the foot more freedom of movement. The lower stack height of the Glycerin Flex does help keep it more stable than the Glycerin 23, but it also means less cushioning, which is especially noticeable in the forefoot.
Variants
- Glycerin Flex (Black/White - (Women - US 7))
- Glycerin Flex (Coconut/Chateau/Portabella - (Women - US 7))
- Glycerin 23 (Atlantic Deep/Greymist/Coconut - (Men - US 9))
- Glycerin 23 (Black/Black/Ebony - (Men - US 9))
Main Differences for
Marathon Racing
Marathon Racing
Threshold
Marathon Racing
4.5
5.9
Forefoot Energy Return
1.6
4.9
Forefoot Stack Height
25.7 mm
30.3 mm
Weight
5.9
4.4
Heel Stack Height
36.6 mm
39.9 mm
Heel Energy Return
0.7
2.2
Full Comparison
Design
Weight
5.9
4.4
Right Shoe Weight Photo
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Left Shoe Weight Photo
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Weight
262.7 g (9.26 oz)
299.4 g (10.56 oz)
Stack Heights
Stack Height Photo
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Heel Stack Height
36.6 mm
39.9 mm
Forefoot Stack Height
25.7 mm
30.3 mm
Heel-To-Toe Drop
10.9 mm
9.6 mm
Advertised Heel-To-Toe Drop
6.0 mm
8.0 mm
External Shape
3D Model Full Shoe
Preview 3D
Preview 3D
Outsole Heel Width
91 mm (3.6")
93 mm (3.7")
Outsole Arch Width
85 mm (3.4")
77 mm (3.0")
Outsole Forefoot Width
113 mm (4.5")
113 mm (4.5")
Heel Width-To-Stack Ratio
2.49
2.33
Forefoot Width-To-Stack Ratio
4.39
3.72
Internal Shape
3D Model Internal
Preview 3D
Preview 3D
Internal Length
281 mm (11.1")
280 mm (11.0")
Internal Heel Width
66 mm (2.6")
65 mm (2.6")
Internal Forefoot Width
95 mm (3.7")
93 mm (3.7")
Wide Sizing Available
No
Yes
Forefoot Fit: Width
9.7
8.2
Forefoot Width Photo
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Ball-Of-Foot TTS Deviation
1.7 mm (0.066")
5.2 mm (0.206")
Toe TTS Deviation
1.5 mm (0.058")
6.9 mm (0.271")
Forefoot Fit: Height
9.8
10
Forefoot Height Photo
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Toe TTS Deviation
-0.7 mm (-0.028")
-0.1 mm (-0.004")
Arch Fit: Width
6.4
7.6
Arch Fit Photo
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Arch Width TTS Deviation
-5.3 mm (-0.209")
-3.9 mm (-0.154")
Length Fit
10
10
Toe Clearance Photo
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Other Features
Other Features Photo
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Tongue Gusset Type
Non-gusseted
Non-gusseted
Plate
None
None
Performance
Heel Energy Return
0.7
2.2
Heel Compression Video
Heel Energy Return
Preview Graph
Preview Graph
Heel Energy Return
62.4%
68.3%
Forefoot Energy Return
1.6
4.9
Forefoot Compression Video
Forefoot Energy Return
Preview Graph
Preview Graph
Forefoot Energy Return
66.9%
71.7%
Heel Cushioning
7.6
7.7
Heel Cushioning Picture
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Heel Cushioning
Preview Graph
Preview Graph
Energy Absorbed At 550N
3.68 J
3.08 J
Energy Absorbed At 1100N
9.24 J
9.86 J
Energy Absorbed At 1900N
15.10 J
17.27 J
Forefoot Cushioning
6.6
7.1
Forefoot Cushioning Picture
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Forefoot Cushioning
Preview Graph
Preview Graph
Energy Absorbed At 800N
4.17 J
4.36 J
Energy Absorbed At 1300N
7.06 J
7.60 J
Energy Absorbed At 2050N
10.22 J
11.21 J
Heel Firmness
5.5
4.8
Heel Firmness
Preview Graph
Preview Graph
Firmness At 550N
46.1 N/mm
47.3 N/mm
Firmness At 1100N
129.2 N/mm
106.4 N/mm
Firmness At 1900N
253.1 N/mm
198.8 N/mm
Forefoot Firmness
8.5
8.1
Forefoot Firmness
Preview Graph
Preview Graph
Firmness At 800N
120.3 N/mm
111.3 N/mm
Firmness At 1300N
260.2 N/mm
220.5 N/mm
Firmness At 2050N
463.3 N/mm
426.1 N/mm
Forefoot Long Run Cushioning
5.4
6.3
Forefoot Long Run Cushioning
Preview Graph
Preview Graph
Energy Absorbed At 10km
6.04 J
6.88 J
Energy Absorbed At 20km
5.82 J
6.73 J
Energy Absorbed At 30km
5.71 J
6.66 J
Energy Absorbed At 40km
5.64 J
6.61 J
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Brooks Glycerin Flex
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Comments
Brooks Glycerin Flex vs Brooks Glycerin 23: Main Discussion
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