Brooks Ghost 15 vs. Brooks Glycerin 21


Brooks is the most popular running shoe brand on the planet, and for good reason. They have had a sole focus on manufacturing running shoes for the last 48 years. They’ve combined technology and runners’ feedback to create their popular line of running shoes. And that line covers a wide range of runners and strides.

Runners across the globe have their favorite Brooks shoe. We know it can be difficult to choose when you’re trying to decide which one to purchase.

Today we’ll be looking at two of the most popular options: the Brooks Ghost and the Brooks Glycerin.

Both of these models are neutral shoes, and while there are similarities, there are some very noticeable differences.

We’ll look at those differences and do a side-by-side comparison so that you can decide which of shoe best suits your running needs.

Let’s have a look at what’s new and different!


The Brooks Ghost 15 upper has been updated with Air Mesh. The material has a bit more stretch and feels softer on the foot. It’s perforated, and this allows for better air circulation, which helps keep your feet cool while you run.

The upper is padded and plush, but it provides a good amount of support. It will feel as if the upper is hugging your foot, while remaining spacious enough for your foot to move naturally.

Brooks has also made changes to the upper of the Glycerin, now made from a double jacquard mesh.

This material is also very flexible. It allows for natural movement of your foot as you go through the heel-to-toe flex. You won’t have any hot spots in the shoe while you’re running, as the new upper is extremely breathable.

Even though the current update doesn’t use traditional overlays like previous Glycerin versions, the 3D Fit Print saddle will give you a secure fit and you’ll feel as if you’re locked in around the midfoot. It’s seamless, and this will leave you chafe-free on runs of any distance.

The padded tongue is sewn into an internal bootie that provides you with a snug and plush fit. Another new feature that you’ll notice is that the shoelaces feel sticky. It’s a little, thoughtful upgrade that prevents them from slipping and coming undone. This also means no more double knots!


When you slip your feet into the Brooks Ghost, you’ll notice that the shoe is not overly soft, but it still provides a stable and balanced ride. The midsole features a dual-layer of cushioning, as it has DNA Loft foam on the lateral side and BioMogo foam on the medial side.

With a co-molded midsole, there are no gaps where the two foams meet. A full-length DNA Loft cushioning layer offers the runner a smooth transition from heel to toe.

While the Glycerin has shed some weight, you won’t find this shoe lacking anything when it comes to the midsole. Featuring tons of DNA Loft foam, you’ll notice that this shoe is soft and but still responsive. It has a stack height of 21 millimeters in the forefoot and 31 millimeters in the heel.

On long runs, you’ll feel how responsive the cushioning is, especially as you pick up the pace. You can’t miss that bouncy responsiveness, which has great propulsion and will take a little bit of the work away from your calf muscles.


If you compare the Ghost 15 to previous versions, you’ll notice that Brooks has updated the outsole a bit.

While it maintains the shape we have come to know and love on the Ghost, they have changed the traction pattern. This helps to provide a smoother transition and offers more stability when you’re moving.

You’ll find the rubber outsole is thicker than most of Brooks’s other shoes. The Ghost 15 has soft blown rubber on the forefoot and hard-wearing rubber in the heel. You’ll find that, with this combination, you’ll have smooth transitions.

The forefoot is flexible, as it has three flex grooves that run the width of the shoe. These give you a responsive toe-off with a smooth and comfortable ride from start to finish.

The outsole on the Glycerin 21 has a blown rubber on the forefoot with HPR Plus rubber on the heel of the shoe, making it more durable for heel strikers.

While the outsole is slightly less thick than previous versions, it does improve the foot landing. And it still provides great protection from the impact of foot strikes.

Brooks also changed the length of the flex grooves, as they only run half the width of the shoe and provide flexibility and help with natural movement of your foot. You’ll find that you can still run confidently even in wet conditions and over uneven surfaces, as it provides great traction.

Other Features

Heel to Toe Drop

The Ghost has a heel-to-toe drop of 12 mm. While the Glycerin has a drop of 10 mm. Most runners won’t notice the small difference between the drop on these shoes.

It’s not the highest, but it’s significant enough to give a decent bit of forward lean when running. Both shoes fall in the usual range for traditional drop heights.

If this is the main feature you care about, neither shoe comes out on top!


Brooks has done well to try and shed some weight on the Glycerin, but it’s still fairly heavy. The men’s shoe weighs 10.2 oz (289 grams), while the women’s shoe weighs 9 oz (255 grams). There are slight weight variances in the different shoe sizes, but it’s not by much.

The Ghost 15 shoes are a shade lighter, with the men’s weighing 10.1 oz (286 grams) and the women’s shoe weighs 8.8 oz (249 grams).

Even though the Glycerin is slightly heavier, you may find that the superior cushioning is worth a few extra grams on the run.

Either way, although the Ghost is the lighter of the two, both of them are fairly easy on the feet.

Firmness & Support

With the addition of extra cushioning in the Glycerin 21, you’ll find this model to be softer than its previous versions. Strangely, despite this, the shoe manages to be firmer than previous versions of the shoe at the same time.

A better mix of cushioning and support, plus the slightly more rigid structures of the upper, helps to increase the firmness and responsiveness of the shoe.

The Ghost 15 will make you feel as though you’re walking on fluffy clouds, and the plush feeling won’t desert you even on the long runs. It’s a neutral shoe, so it will be perfectly comfy for runners who have a neutral foot.

Those who overpronate may find both of these shoes to be uncomfortable, as neither will provide the necessary support, being neutral shoes. Runners with high arches or those who underpronate may or may not find it to be comfy, depending on their taste.

Whether you’re just starting out or you’re an experienced runner, if you have a neutral foot, you’ll find both shoes to provide a smooth and comfortable ride. It’s just a matter of choosing which one suits your particular foot better.


Brooks is very good when it comes to pricing their shoes. They take care to ensure that the price doesn’t vary from retail stores to online.

In general, you’ll find that the Glycerin is around $20 dollars more expensive than the Ghost 15. As similar as the shoes are, the Glycerins are technically the higher-end pair.

If the price is off-putting, remember that before Brooks releases the updated version of a shoe, you can find the shoes at 10 to 15% off.

If you do like the Glycerin more than the Ghost, and you can’t get it on special, $20 is a small price to pay for the superior cushioning and comfort it offers.


Both Ghost 15 and the Glycerin 21 are good running shoes. You may still find it difficult to choose between the two. They’re both neutral running shoes that have good support and cushioning, durable outsoles, and are competitively priced.

That being said, the Ghost 15 would be better for runners who run on a daily basis and for those who run long distances. The cushioning is responsive, you’ll have great energy return, and you’ll find that even after running 20 miles, your legs will feel fresh.

If you’re a runner who has mild overpronation or underpronation, you’ll most likely find this shoe to be supremely comfortable, even if you have high arches.

The Brooks Glycerin 21 may be a little heavy for some people to take on long runs, as you could feel that it weighs you down. That being said, it’s a great neutral shoe that can be used daily for shorter runs.

Despite the slightly heavier weight, you’ll most likely find yourself running faster in this pair of shoes, even if you’re running a half marathon.

Photo of author


Ben is an avid road and trail runner, and has completed multiple marathons and ultras. A former running store owner, he now shares his knowledge and experience writing these articles.