Can I go straight from the Brooks Glycerin 19 to the Glycerin 21 and skip the Glycerin 20?

Yes, but going Glycerin 19 to Glycerin 21 means taking one change in a single step: the Glycerin 20 is where the ride moved. Drop holds at 10 mm, so the difference is foam and fit rather than geometry: DNA Loft, softer density to Nitrogen-infused DNA Loft v3.

How much did the weight change across these two updates?

0.4 oz off in total, 10.2 oz to 9.8 oz in a men's US 9. The Glycerin 20 took it to 10.5 oz first.

Is the Glycerin 20 the better buy than either of these?

On paper it splits them: 10.5 oz against 10.2 oz for the Glycerin 19 and 9.8 oz for the Glycerin 21, on a 34 mm heel and a $160 list price. Whether that is worth chasing depends on what the Glycerin 20 update actually did, which the section above works through.

Did the Glycerin get taller between the Glycerin 19 and the Glycerin 21?

Heel stack went 31 mm to 38 mm, by way of 34 mm on the Glycerin 20. Drop held at 10 mm throughout, so the extra foam sits under both ends.

Where does the Glycerin 21 sit in the Glycerin lineup now?

Two versions on from the Glycerin 19, and already replaced itself: the Glycerin 22 arrived in 2025. If you are shopping old stock anyway, price the Glycerin 21 against it before deciding.

Brooks Glycerin 19 vs Glycerin 21

Two versions apart. Updated September 10, 2026. Specs are men's US 9.

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THE SHORT ANSWER

Two updates and 2 years separate the Brooks Glycerin 19 from the Glycerin 21. Net change: 0.4 oz lighter, 7 mm more heel stack, a new midsole, $10 more at list. The Glycerin 20 is where the character changed, and that is the update Glycerin 19 owners notice first.

Glycerin 19 · 2021

Glycerin 21 · 2023

The two updates in between

Each step has its own page with the full change list and the verdict on that update.

Step 1Glycerin 19 to Glycerin 202022Changed character
Glycerin 19 vs 20 What replaced the Brooks Glycerin 19?
Step 2Glycerin 20 to Glycerin 212023Refined, same shoe
Glycerin 20 vs 21 What replaced the Brooks Glycerin 20?

Glycerin 19 vs Glycerin 21: every spec, side by side

The net of both updates. Per-update change notes stay on the step pages above, because they explain changes measured from a different starting point than this table uses.

Spec	Glycerin 19	Glycerin 21
FIT AND WEIGHT
Weight	10.2 oz	9.8 oz
Widths	D, 2E	D, 2E
Upper	Engineered mesh	Engineered warp knit
CUSHIONING GEOMETRY
Heel stack	31 mm	38 mm
Forefoot stack	21 mm	28 mm
Drop	10 mm	10 mm
MATERIALS
Midsole	DNA Loft, softer density	Nitrogen-infused DNA Loft v3
VALUE
List price at launch	$150	$160

Or buy the Glycerin 20 instead?

The Glycerin 20 is worth a look only if you want the ride it introduced, because that is the update that changed the shoe. Buying it to soften the jump does not work: you would be adapting to the same change either way, just at an older spec.

Buy the Glycerin 20

Sizes running out

Discontinued at retail. Amazon carries what remains, so treat an in-stock size as a closing window, and expect prices to swing.

Men's: Check remaining stock Women's: Check remaining stock

Availability last checked Aug 3, 2026.

Questions runners ask

Can I go straight from the Brooks Glycerin 19 to the Glycerin 21 and skip the Glycerin 20?: Yes, but going Glycerin 19 to Glycerin 21 means taking one change in a single step: the Glycerin 20 is where the ride moved. Drop holds at 10 mm, so the difference is foam and fit rather than geometry: DNA Loft, softer density to Nitrogen-infused DNA Loft v3.
How much did the weight change across these two updates?: 0.4 oz off in total, 10.2 oz to 9.8 oz in a men's US 9. The Glycerin 20 took it to 10.5 oz first.
Is the Glycerin 20 the better buy than either of these?: On paper it splits them: 10.5 oz against 10.2 oz for the Glycerin 19 and 9.8 oz for the Glycerin 21, on a 34 mm heel and a $160 list price. Whether that is worth chasing depends on what the Glycerin 20 update actually did, which the section above works through.
Did the Glycerin get taller between the Glycerin 19 and the Glycerin 21?: Heel stack went 31 mm to 38 mm, by way of 34 mm on the Glycerin 20. Drop held at 10 mm throughout, so the extra foam sits under both ends.
Where does the Glycerin 21 sit in the Glycerin lineup now?: Two versions on from the Glycerin 19, and already replaced itself: the Glycerin 22 arrived in 2025. If you are shopping old stock anyway, price the Glycerin 21 against it before deciding.