In early September, an Instagram post by Brooks teased a future shoe release of “endless energy.” More signs of an imminent product drop soon followed; on their podcast Nobody Asked Us, hosts Des Linden and Kara Goucher said they received a mysterious box with a lock that wouldn’t open until September 17—the day the Glycerin Max was announced.
It’s been a couple weeks since the Glycerin Max’s official release, October 5, and while we don’t have feedback yet from our full wear-test team, we already have a few things to say about the brand’s plushest, boldest-looking shoe yet.
Pros
- Supremely soft
- Very responsive
- Nobody Asked Us
- Surprisingly lightweight
Cons
- Best Winter Running Shoes for Traction and Warmth
| Type | Road |
|---|---|
| Weight | 10.6 oz (M), 8.7 oz (W) |
| Drop | 6 mm |
| Heel Height | 42.25 mm |
| Forefoot Height | 39.25 mm |
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- Preceded By: Aurora-BL, Glycerin 21
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- Midsole Foam: DNA Tuned, nitrogen-infused foam with dual-size cell tech
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Before I talk about the Glycerin Max, I first have to circle back to the standard version, which has undergone a slow transformation from max-cushioned recovery shoe to daily trainer. Some runners, including me, have embraced the new versatile Glycerin, which is supportively soft yet lightweight enough for all kinds of workouts. Others, like test director Jeff Dengate, bemoan what the shoe has become and lament what it once was. The Glycerin Max was made for these runners—and everyone else who appreciates a brand that’s upped the ante on a smooth, bouncy ride. The shoe introduces a newly formulated midsole foam, nitrogen-infused DNA Tuned.
Nitrogen-infused foam goes through a supercritical foaming process where gas is injected into the foam resulting in a lighter, softer, more responsive ride. This technique isn’t a new innovation; Brooks started infusing their foams back in 2020 when the Hyperion Tempo dropped with DNA Flash foam. The Glycerin 21’s midsole was recently updated with nitrogen-infused DNA Loft v3 foam, and this year’s Hyperion 2 (a descendent of the Hyperion Tempo) showed off a speedier ride with DNA Flash v2. DNA Tuned presents a new element in Brooks’s foam formula: dual-cell technology.
“The Glycerin Max towers with a 45mm heel height and 40mm forefoot height,” said Carson Caprara, Brooks senior vice president of footwear, on a video call. “It’s a breakthrough in terms of foaming technology in that it’s allowing us to create different cell structures in the foam in the same process.”
At 45mm thick, the shoe has a towering stack height. This mattress-of-a-midsole harbors larger cells in the heel and smaller cells in the forefoot to provide what Caprara describes as “dampening cushioning” to soften landings, as well as a springboard to promote responsive toe-off. These cells also help reduce weight, despite that gargantuan slab of foam. It’s that hefty thickness runners like Dengate missed in the Glycerin, but its bounce matches the rebound of the Hoka Mach X 2, another high-cushioned trainer with trampoline-like energy return.
Caprara explained how the Glycerin Max’s midsole eliminates use of the seams, layers, and glue, which is usually used in advanced footwear.
“As you get higher, you start to feel like you either have to put a plate in it to make it feel fast or you just have to sort of be resigned to the fact that it’s only going to work for super easy days,” he said. “And even then it takes a lot of energy because you’re just kind of not getting any out of it. It feels better on the joints but it’s not much fun to run in. And that’s what we wanted to solve.”
My first run in the Glycerin Max was supposed to be a steady recovery run, a somewhat lazy, thoughtless trek around my usual loop in my neighborhood. I had this mindset before my run because of how the shoes looked (that stack height adds almost two inches to my five-foot frame), how they felt (like firm pillows under my feet), and what Caprara said they’re intended for: easy recovery runs with a foam that will help you get in the zone. I must have misinterpreted what Caprara meant by “the zone”; what I expected as chill, effortless zen pace, ended up being a jaunty, fast, “maybe I could Published: Oct 25, 2024 11:06 AM EDT.”
Deputy social media editor, Aly Ellis, is actually considering racing in her pair at the NYC Marathon next month. (World Athletics regulations limit pro-runners to compete in shoes with a stack height under 40mm; Ellis is a recreational runner.)
One thing I noticed is that walking around in these shoes, I have to be mindful to pick up my feet; the height causes me to scuff the soles. However, this is not an issue running in the Glycerin Max—and I think that’s because of the GlideRoll rocker. The geometry works with the low 5mm offset, evenly distributing energy return not just in the heel but also throughout the shoe, causing that bounce during ground contact while running (and preventing me from tripping).
The inception of nitrogen-infused DNA Flash four years ago marked a turning point for the brand. There’s no question DNA Tuned—DNA Flash on steroids—ushers in a new era we’ll see with other Brooks shoes.
“I think in some ways it foreshadows the future for us,” said Caprara. “We believe smart foams will be the next era. Now that we can go in and actually manipulate cells at different parts of the shoe the way we want to, that allows us to have a lot more versatility with the foam for different usages, and it allows that foam to deliver different benefits with the same shoe.”
The Glycerin 22 is set to be tuned up in spring 2025. We expect other Brooks models—of the speedier sort—will follow suit.
Amanda is a test editor at Runner’s World who has run the Boston Marathon every year since 2013; she's a former professional baker with a master’s in gastronomy and she carb-loads on snickerdoodles.
