I ran 35 miles in the Brooks Glycerin Flex and it might change the way you think about running shoes

Brooks makes a lot of cushioned running shoes. The Brooks Glycerin itself comes in both standard and stable versions, and the Brooks Glycerin Max 2 is a more cushioned and rockered option in the lane.

Then there’s the Brooks Ghost line of shoes, which includes several options for both road and trail running.

So it is notable that in such a crowded line-up the Brooks Glycerin Flex does stand out as something different, and that’s also true compared with the market at large. Most shoes now opt for stiff, rockered designs with huge stacks of foam in the midsole, but the Flex aims to create a more natural, flexible ride.

It does succeed in being different from max-cushioned shoes, and I think it will be an important shoe in making runners consider different styles of sneakers. However, for those not drawn in by its flexible feel, the Glycerin Flex doesn’t hit the performance heights of the best running shoes I’ve tested.

Brooks Glycerin Flex review: price and availability

The Brooks Glycerin Flex was announced in December 2025 and went on sale in early February 2026. It costs $170 in the U.S. and £165 in the U.K., making it $5 cheaper than the Glycerin 23 and $30 cheaper than the max-stack Glycerin Max 2, but more expensive than the Brooks Ghost line-up of shoes.

Brooks Glycerin Flex review: design and fit

The Glycerin Flex is currently available in four colors, including the white/green design that I tested. It fit me well in my normal running shoe size, the same size I’ve used for Brooks shoes for many years.

While it’s not as maxed-out on cushioning as many shoes, the Glycerin Flex still has a lot of foam in the midsole and stands 36mm tall at the heel and 30mm tall at the forefoot for a 6mm drop.

In the past, runners craving flexibility and a more natural ride might have gone for very low-stack or even barefoot-style shots, so the Glycerin Flex offers a more cushioned approach.

At 9.6oz in my US men’s size 10, the Glycerin Flex is a bit lighter than other Brooks shoes, including the Glycerin Max 2, partly thanks to the fact that it isn’t as cushioned.

Upper

The Glycerin Flex has a flat knit upper that is much less structured than traditional Brooks uppers, with only a minimal heel counter and no real overlays, in keeping with the flexible theme.

I found the upper comfortable and breathable throughout my runs, and it held my foot securely around the heel and midfoot.

Midsole

The Glycerin Flex uses Brooks’ DNA Tuned foam, which is a dual-density material with a softer feel at the back of the shoe to cushion landings, and a more responsive feel in the forefoot to add more energy return to your toe-offs.

This is the same foam as used on the Glycerin 23 and Glycerin Max 2, but the big difference with the midsole on the Glycerin Flex is the S-groove on the bottom of the shoe, and the cutouts that allow different areas of the forefoot to move independently.

You can bend, twist, and flex the shoe in a way that isn’t at all possible with stiffer cushioned shoes that often guide you through your footstrike using rockers. The Glycerin Flex is instead designed to let your foot move as naturally as possible as you run.

Outsole

There’s a thick layer of rubber covering most of the bottom of the Glycerin Flex, which bodes well for its durability, and I had no trouble with the grip of the shoe myself, even in wet conditions.

Brooks Glycerin Flex review: running performance

Running in the Glycerin Flex is not as wildly unlike stiffer cushioned shoes as you might expect, but it is a different sensation, especially as you roll through from the midfoot to the forefoot.

At this point, the flexible segments in the shoe come into play, and you can feel each of them hit the floor in turn, giving you more ground feel and a more natural ride feel compared to rockered shoes that are more active in pushing you through your stride pattern.

The heel of the shoe is well-cushioned and feels comfortable, similar to other running shoes, with the flexible feel only really noticeable in the forefoot.

I have no problem running in very stiff shoes with rockers or plates in their midsole, though, so how highly I rated the Glycerin Flex came down to its performance, and it’s not an especially lively or comfortable shoe.

It’s pretty comfortable, but the downside of the more natural feel in the forefoot is that it isn’t as cushy and soft as max-cushioned shoes, and the Glycerin Flex isn’t a very springy shoe. I found it only worked really well for me at easy paces, whereas other cushioned daily trainers have a bit more energy return at faster speeds.

Should you buy the Brooks Glycerin Flex?

Unless you’re fully sold on the benefits of its flexible ride, the Glycerin Flex doesn’t offer enough to make it a top pick for me.

I prefer the more comfortable, rockered ride of the Glycerin Max 2 myself for easy runs, and outside of Brooks, there are springier cushioned options like the Nike Vomero Plus or R.A.D UFO.

Even if you're craving a more natural ride from your daily trainer, I think you can get a similar effect by opting for a lower-stack shoe, like the Hoka Mach 7 or Puma Velocity Nitro 4, which provide more ground feel while being lighter, cheaper, and better than the Glycerin Flex for faster runs.

They’re not as flexible, though, and clearly that is the major selling point of the Glycerin Flex. I do like that Brooks is innovating in this direction and providing a counterpoint to stiff shoes, but I would have liked it to be a more exciting shoe to run in, regardless of flexibility.