hylo Impact Review: Run Like the World Depends On It

All shoes are reviewed by the Fleet Feet tester team, which represents a wide variety of goals, foot shapes, running locations and terrains. Reviewers pound the pavement, climb the hills, tackle the trails, then come together to compare notes. Debates ensue over the feel of the cushioning, the purpose of the shoe, and how it compares to last year’s model. While each reviewer has their own individual preferences, we hope that capturing our debates will help you make an informed decision.

The hylo Impact is built for runners who care about their impact—both on the road and on the planet.

A UK-based company with a focus on sustainability, hylo designed the Impact using bio-based materials and a supply chain that prioritizes local sourcing and reduced emissions.

With hylo’s Hyloop™ recycling program, you can bring your worn hylo shoes back to Fleet Feet. Once the Hyloop™ recycling bin fills up, the shoes will be ground up and sorted through, with some parts being used to make new hylo shoes.

This shoe isn’t just light on your feet—it’s lighter on the environment. But does it deliver when it comes to comfort and performance? Read on to find out.

Before we dive into the review, it’s worth noting the ways the Impact is a sustainable, eco-friendly option for your next run.

• Hylo’s supercritical nitrogen-infused midsole foam is blended with sugarcane, a bio-based material with less environmental impact than petroleum-derived plastics.
• The upper of the Impact uses a material made with castor beans and Tencel™ Lyocell, a semi-synthetic fiber made from wood pulp.
• The production process emphasizes keeping materials “in the loop.” Excess materials from production can be recycled, along with samples that can no longer be worn.
• The supply chain prioritizes materials that can be sourced close to the factory, reducing transportation emissions. Hylo also reduces emissions by using land and sea transportation rather than air freight.

Using a Life Cycle Assessment (LCA) to measure the environmental impact of the materials and processes used, including packing, shipping and retail, hylo says the Impact has a 40% lower carbon footprint per stride than than the average running shoe.

So how does the fit and feel of hylo Impact compare to the average running shoe?

While we’ve tested shoes made with nitrogen-infused midsoles before, we’ve never worn ones made with this much bio-based material.

“I was, admittedly, a bit wary about trying the Impact. For years, companies have been trying to crack the code on making a premium-quality running shoe while keeping it eco-friendly. Many have failed,” says Brandon, one of our most experienced shoe testers. “However, I was impressed with the underfoot feeling in this shoe. I thoroughly enjoyed how soft and bouncy the midsole felt. It provides some nice energy return, despite not having a plate.”

I wore the hylo Impact for a 7-mile easy run. The cushioning felt soft and flexible, which I really appreciated. My feet and calves tend to get cranky in stiff shoes, so the Impact felt perfect to me. While I wouldn’t put this shoe on for a fast workout, I did some 30-second pickups on a whim and the Impact was able to keep up. They felt nice and smooth at a fast pace, but they really shined while I was just cruising.

Max and Tom agreed that the Impact falls on the softer side of the spectrum.

“The Impact feels incredibly light on foot and the midsole is soft and bouncy, though maybe lacks a little if you’re looking for a hyper responsive ride,” says Tom. “It’s one of those shoes that you can’t help but shift your weight back and forth over just to feel how the cushioning reacts. Running in them felt smooth and natural, and the shoes seemed to really open up and feel like an extension of my foot after a few runs.”

On the other hand, Kate found it to be rather firm. However, Kate prefers firm shoes so this is a compliment from her.

“My first run in the Impact was a six-miler on very hilly roads,” Kate says. “The Impact has a very natural feel on the run. The cushion definitely can compete head to head with the other top shoes out there. It has good impact absorption, and I like that it’s fairly firm and not super squishy.”

Not only did I enjoy the feel of the cushioning underfoot, I was especially delighted by the outsole’s grip. I wore these on a morning after some heavy rain, and the traction was great. There’s this one bridge on my route that gets really slippery when wet, but I felt solid in my footing in the Impact.

The outsole uses vertical rubber strips, which hylo says are inspired by racing tire technology (any Formula One fans out there?) The grooves in between the strips are meant to displace water, helping you maintain ground contact to keep your stride steady.

I don’t think I’ve ever run in shoes made with castor beans, so this was a first for me. The material in the forefoot feels silky and stretchy, with plenty of large perforations for ventilation. It becomes a bit thicker and more structured in the midfoot and heel to hold your feet in place. The tongue feels soft and flexible, and a handy pull tab in the heel helps you slide the shoes on with ease.

The hylo Impact is offered in unisex sizing, so women should order 1.5 sizes down from their typical size. For example, I wear a women’s 6.5 and received a men’s 5. I found the shoes to fit mostly true-to-size, but they felt a little bit long. I had a little bit more toe space than I’m used to, but I think going down half a size would have been too small. I laced them up, tied the marathon loop for good measure, and had no issues on the run.

Kate agrees.

“The first time that I wore the Impact, I thought my shoe was too long—maybe by a half size,” she says. “But when I tried it the second time, I realized I probably didn't take the time to really dial in the lacing and the fit. After a little bit of time snugging everything up all over, I’ve got a secure fit in the heel and midfoot; I’d maybe shorten the toe a bit if I could, but it’s worth taking the time to really adjust everything. In the end it worked well for me.”

Tom found the fit to be just a hair long, like Kate and I, while Brandon mentioned the upper bunching up a bit at the laces when cinching down the fit.

However, Max found his perfect fit in the Impact. He has long, narrow feet, which could have something to do with it.

“The upper is stretchy and accommodating, with a thin, gusseted tongue,” he says. “ Overall the Impact fits very true to size in my experience in width, length and volume.”

Not sure about the width, length or volume of your feet? Your best bet will be to head into your local Fleet Feet. Fleet Feet outfitters use 3D fit id® foot scanning technology to gather information about your feet and the support they need by taking precise measurements of your foot length, width and arch height, so you can learn a lot about your feet while you’re there.

We took a look at some comparable options to see how the hylo Impact stacks up. Here’s what we found.

We found the hylo Impact to feel most similar to the On Cloudsurfer 2 and Karhu Mestari Run 1.5. All shoes are similar in stack height (the difference between your feet and the ground) and heel-to-toe drop (the difference in height between your heel and forefoot). However, there are some key differences.

I found the hylo Impact to feel much softer, squishier and more flexible than the Cloudsurfer, which is a bit firmer and springier, or the Mestari Run, which is stiffer with a decidedly more pronounced rocker shape.

For runners who want a soft, flexible, versatile option, the Impact is a great choice. It’s also perfect for those who care deeply about sustainability and are ready to put their money where their mouth is.

While the Impact is a great daily trainer for anyone who prioritizes sustainability, just because it’s better for the planet doesn’t mean it’s a lesser shoe,” Tom says. “The hylo Impact can hang with the best of them. I would have no hesitation recommending this shoe as an option for a half marathon or even a full marathon depending on the runner. It’s a great choice for anyone who prefers a touch of softness.”

While this shoe won’t give you a speed advantage the way a plated shoe will, we all agree that its lighter weight helps us feel quick on our feet. And, as Max put it, the shoe isn’t meant for speed but more so to “eat up some serious miles during long runs and easy runs.”

“To create a recyclable shoe that is actually comfortable to run in is an incredible accomplishment, and one that can make a meaningful impact to our planet and future generations,” Kate says.