Our verdict

By enhancing the predecessor's weaker aspects while preserving the model's essence, Saucony has hit the mark again with the Endorphin Speed 4. In our tests, we found this supertrainer to still be a lightweight, bouncy, and versatile shoe that easily adapts to all paces. It's now even more cushioned and spacious, making it more comfortable than ever in long runs. Despite a slight increase in weight and a lacing system that might not suit everyone, we're still eager to recommend the ES4 for its outstanding value and performance.

Pros

  • Remains lightweight
  • Excels at all paces
  • Great for track workouts
  • More spacious fit
  • Bouncy and enjoyable ride
  • Enhanced stability over v3
  • Suits daily training
  • Exceptional value

Cons

  • Slightly heavier than predecessor
  • Could be a bit firm for some

Audience verdict

83
Good!
  • Top 7% most popular running shoes

Who should buy

We've concluded that the Endorphin Speed 4 is an outstanding pick for:

  • Runners desiring a high-performance, all-around shoe that can even handle easy runs.
  • Athletes looking for an interval shoe without a carbon plate.
  • Fans of the Endorphin Speed series seeking a return to a firmer, more responsive ride from the softer v3.

Saucony Endorphin Speed 4

Who should NOT buy

While the Endorphin Speed saga aims to serve a broad audience, we believe there are better choices for certain runners.

For those who prefer a non-plated shoe, the ASICS Superblast might be a more suitable option. It's almost as light as the Endorphin Speed 4 but offers more foam for cushioning, lacks the nylon plate for a more traditional feel, and provides greater stability, albeit at a higher price point.

Saucony Endorphin Speed 4 parts

Moreover, we feel the ES4 may not be the ideal option for those who favour super-soft running shoes for speed training. The Nike Streakfly provides a plush experience at a more affordable price.

Breathability

The moment we unboxed the Endorphin Speed 4 in our lab, the massive ventilation holes immediately grabbed our attention. They played a key role in the shoe scoring a perfect 5/5 in our smoke test.

Our initial impressions were confirmed when we held the upper against a powerful light. Indeed, it's among the most ventilated uppers we've encountered. However, for those planning to use it in colder climates, we recommend pairing it with thick socks for added warmth especially during easy runs.

Intrigued by the ventilation holes, we went in for a closer look with our lab's microscope.

Saucony Endorphin Speed 4 microscope

The engineered mesh is finely tuned to maximise airflow in the toebox while maintaining a robust structure throughout the shoe.

Saucony Endorphin Speed 4 micro

Examining the entire upper, we noted Saucony's focus on creating a highly breathable shoe, not just in the toebox—which is common—but also with significant ventilation in the tongue and medial side, a rarity in running shoes.

Test results
Endorphin Speed 4 5
Average 3.8
Compared to 234 running shoes
Number of shoes
1
Breathability
5

Durability

Toebox durability

Our initial foray into the durability of the Endorphin Speed 4 focused on the toebox—an area of concern due to its huge ventilation holes. And we're delighted to share that the shoe held up impressively in our Dremel test, securing a 3/5 rating. 

While this may seem like an average score, it's actually a commendable achievement for a well-ventilated mesh upper, demonstrating remarkable resilience. In fact, our testing revealed that even those prone to wearing holes in their shoes, whether at the big toe or pinky toe, can confidently opt for this model.

Saucony Endorphin Speed 4 Toebox durability
Test results
Endorphin Speed 4 3
Average 2.4
Compared to 168 running shoes
Number of shoes
1
Toebox durability
5

Heel padding durability

Another area that often shows early signs of wear is the heel padding—many runners find their Achilles rubbing against this spot, causing concern for durability. To evaluate the potential for damage here, we conducted another test, pulling out the Dremel and applying the same force as before. To our delight, the results were outstanding.

We were thrilled to award the ES4 a perfect 5/5, the highest possible score!

Saucony Endorphin Speed 4 Heel padding durability
Test results
Endorphin Speed 4 5
Average 3.2
Compared to 164 running shoes
Number of shoes
1
Heel padding durability
5

Outsole hardness

Riding high from two successful initial tests, we turned our attention to the outsole. We began by measuring its hardness, which came in at 77.0 HC on our durometer.

Saucony Endorphin Speed 4 outsole

The Endorphin Speed 4 introduces a new outsole design that enhances traction while maintaining a considerable amount of exposed foam.

This is a bit softer than what we typically encounter. Our tests showed that this softer approach likely contributes to its strong grip across various terrains, such as asphalt, tracks, and even dirt roads.

Saucony Endorphin Speed 4 Outsole hardness
Test results
Endorphin Speed 4 77.0 HC
Average 80.5 HC
We use an average of four tests. The photo shows one of those tests.
Compared to 285 running shoes
Number of shoes
52.1 HC
Outsole hardness
93.0 HC

Outsole durability

Our main concern was the potential for early wear due to the slightly soft rubber. To address this, we decided to conduct one final test using the Dremel.

We were pleased with the outcome—after completing the test, we discovered a mere 0.8 mm indentation. This result is quite promising!

Saucony Endorphin Speed 4 Outsole durability
Test results
Endorphin Speed 4 0.8 mm
Average 0.9 mm
Compared to 146 running shoes
Number of shoes
0.0 mm
Outsole wear
2.0 mm

Outsole thickness

Finally, we examined the outsole thickness. Saucony maintained the exact 2.0-mm thickness from the Endorphin Speed 3. Although it might seem thin at first glance, remember that we're looking at a performance-oriented, lightweight running shoe.

Saucony Endorphin Speed 4 outsole thick

In such models, minimising weight is crucial, and a thicker outsole could mute the ride's responsiveness and add unnecessary bulk. From our standpoint, a 2.0-mm rubber outsole strikes a perfect balance for this shoe type, offering a nimble feel without sacrificing durability.

Saucony Endorphin Speed 4 Outsole thickness
Test results
Endorphin Speed 4 2.0 mm
Average 3.2 mm
Compared to 304 running shoes
Number of shoes
0.0 mm
Outsole thickness
6.6 mm

Weight

Indeed, the shoe feels incredibly light on the foot. Weighing in at just 8.4 oz (237g), it's almost like it vanishes when you're running. Yet, we noted a slight weight increase of 0.5 oz compared to its predecessor, even though the outsole thickness remains unchanged.

Let's uncover the reasons behind this weight gain!

Saucony Endorphin Speed 4 Weight
Test results
Endorphin Speed 4 8.36 oz (237g)
Average 9.38 oz (266g)
Compared to 305 running shoes
Number of shoes
5.26 oz (149g)
Weight
12.56 oz (356g)

Cushioning

Heel stack

The primary cause of the weight increase in the ES4 is its midsole. Using our callipers, we measured an impressive 36.2 mm in the heel area, making it the tallest Endorphin Speed model to date. This is a noticeable 2.1 mm increase from last year's model.

This design aligns with the current market trend of creating shoes with taller profiles for extra cushioning. Despite this increase, the Speed remains comfortably below the 40-mm mark. It's an excellent option for those who prefer a less towering shoe without compromising on long-run comfort.

Saucony Endorphin Speed 4 Heel stack
Test results
Endorphin Speed 4 36.2 mm
Average 33.7 mm
Compared to 304 running shoes
Number of shoes
7.6 mm
Heel stack
45.7 mm

Forefoot stack

The forefoot also sets a new record for the Endorphin Speed series at 27.5 mm.

Saucony Endorphin Speed 4 forefoot

We've observed that this feature makes it exceptionally versatile, ideal for effortlessly tackling both long runs and speed workouts—a hallmark of this all-around model.

Saucony Endorphin Speed 4 Forefoot stack
Test results
Endorphin Speed 4 27.5 mm
Average 25.0 mm
Compared to 304 running shoes
Number of shoes
7.6 mm
Forefoot stack
36.9 mm

Drop

The difference between the forefoot and the heel delivers an 8.7-mm drop, appealing to a broad spectrum of runners.

The Endorphin Speed series is celebrated for its wide appeal across runners with various footstrikes and paces. This popularity stems from its versatile design, not limited to a specific type of runner, but rather embracing a more universal approach. That's why the real 8.7-mm drop makes total sense to us.

Saucony Endorphin Speed 4 Drop
Test results
Endorphin Speed 4 8.7 mm
Average 8.7 mm
Compared to 304 running shoes
Number of shoes
-0.8 mm
Drop
16.1 mm

Insole thickness

Our calliper measured the insole at 5.1 mm, introducing an extra layer of plushness to the underfoot experience.

Saucony Endorphin Speed 4 Insole thickness
Test results
Endorphin Speed 4 5.1 mm
Average 4.5 mm
Compared to 300 running shoes
Number of shoes
1.5 mm
Insole thickness
7.3 mm

Midsole softness

Note: a low durometer measurement equals a soft material, whereas a high measurement means it's firm.

In the midsole, Saucony once again employed its Pebax-based, pellet-shaped PWRRUN PB foam, which has been a game-changer since its debut for its energy return and durability. Yet, there's a slight tweak in the formulation—the shoe now has a firmer feel, confirmed by our durometer reading at 22.3 HA.

The ride is neither too firm nor overly plush; it strikes a perfect balance. We consider this a positive shift from the previous version's softer feel, which some runners found too mushy, enhancing its responsiveness.

However, for those who prefer an ultra-soft midsole, the v3 might be the more suitable option.

Saucony Endorphin Speed 4 Midsole softness
Test results
Endorphin Speed 4 22.3 HA
Average 21.4 HA
We use an average of four tests. The photo shows one of those tests.
Compared to 232 running shoes
Number of shoes
8.5 HA
Midsole softness (soft to firm)
41.5 HA

Difference in midsole softness in cold

As highlighted in our guide on running shoes and temperatures, Pebax foams like PWRRUN PB stand out for their exceptional performance in a variety of climates, making them a top choice for winter running.

To confirm this, we put the ES4 to the test by placing it in the freezer for 20 minutes. The result was impressive—the foam became only 5.6% firmer. 

Saucony Endorphin Speed 4 Difference in midsole softness in cold
Test results
Endorphin Speed 4 5.6%
Average 25.5%
Compared to 231 running shoes
Number of shoes
0%
Difference in midsole softness in cold
100%

Plate

The Endorphin Speed series has consistently incorporated a nylon plate for enhanced stability and a bouncier ride. The ES3 took this a notch higher with a winged plate design, a feature that continues in the ES4.

Coupled with a firmer midsole, it offers what we believe to be the most stable ride across all four versions.

Saucony Endorphin Speed 4 Plate

Stability

Lateral stability test

Stability gets a major boost from smart design features like heightened midsole sidewalls, a revamped heel, and enhanced rigidity. These elements, coupled with the firmer midsole, play a crucial role in the shoe's impressive performance, guaranteeing a secure and stable run across all paces.

Torsional rigidity

From the moment we unboxed and tested the shoe, we noticed it was more rigid than its predecessor. After some deliberation in the lab, we assigned it a 3/5 score for rigidity. This shift makes it lean more towards speed-focused runs rather than daily training, yet it still holds its ground as an all-around shoe.

Test results
Endorphin Speed 4 3
Average 3.2
Compared to 283 running shoes
Number of shoes
1
Torsional rigidity
5

Heel counter stiffness

The heel counter adopts a similar design to many other daily running shoes, featuring just enough rigidity to be noticeable but not overbearing. We found it both comfortable and secure for all distances, including long runs, with zero heel slippage.

Test results
Endorphin Speed 4 3
Average 2.8
Compared to 267 running shoes
Number of shoes
1
Heel counter stiffness
5

Midsole width in the forefoot

Another key factor contributing to the shoe's enhanced stability and slight weight gain is its increased width.

It has expanded to 114.7 mm, which, while still modest, marks a noticeable change for forefoot strikers. However, despite this growth, the Endorphin Speed retains its agile feel.

Saucony Endorphin Speed 4 Midsole width in the forefoot
Test results
Endorphin Speed 4 114.7 mm
Average 113.7 mm
Compared to 305 running shoes
Number of shoes
100.5 mm
Midsole width in the forefoot
126.5 mm

Midsole width in the heel

The heel has also widened to 93.4 mm, nearly 4 mm more than the previous version, enhancing stability for heel strikers. Despite this, it continues to be a purely neutral running shoe and might not be the best speed training companion for those with stability needs. We suggest the Saucony Tempus instead.

Saucony Endorphin Speed 4 Midsole width in the heel
Test results
Endorphin Speed 4 93.4 mm
Average 90.5 mm
Compared to 305 running shoes
Number of shoes
74.9 mm
Midsole width in the heel
106.6 mm

Flexibility

Stiffness

Nylon-based plates, unlike their carbon-fibre counterparts, add minimal longitudinal stiffness to a shoe. Our 90-degree bend test yielded a 29.4N result, nearly identical to what we'd expect from a similarly-stacked shoe without a plate.

This makes it an great choice for daily running, offering a snappy-yet-comfortable experience without the intense rigidity often associated with carbon plates.

Test results
Endorphin Speed 4 29.4N
Average 29.2N
We use an average of four tests. The video shows one of those tests.
Compared to 287 running shoes
Number of shoes
2.2N
Stiffness
94.4N

Difference in stiffness in cold

After another 20-minute session in the freezer, we assessed the stiffness. Just like with the softness, the performance was stellar, showing only a 3.2% increase in stiffness. This result is simply outstanding!

Test results
Endorphin Speed 4 3.2%
Average 35.9%
Compared to 287 running shoes
Number of shoes
0%
Difference in stiffness in cold
148%

Size and fit

Toebox width at the widest part

A significant—and delightful—upgrade in the fourth version of the Endorphin Speed is its upper.

Saucony Endorphin Speed 4 broad

It's now more spacious than ever, comfortably fitting runners with slightly wide feet. We measured its widest part at 101.7 mm, a change that enhances its inclusivity.

Saucony Endorphin Speed 4 Toebox width at the widest part
Test results
Endorphin Speed 4 101.7 mm
Average 98.4 mm
Compared to 305 running shoes
Number of shoes
89.5 mm
Toebox width at the widest part
109.1 mm

Toebox width at the big toe

The upper's widest part enjoyed the overall increase in the shoe's width, but the toe cap area stayed at a comfortable average of 77.5 mm, which suits most feet just fine.

Saucony Endorphin Speed 4 Toebox width at the big toe
Test results
Endorphin Speed 4 77.5 mm
Average 78.2 mm
Compared to 179 running shoes
Number of shoes
60.4 mm
Toebox width at the big toe
92.5 mm

Tongue: gusset type

Saucony chose the semi-gusseted tongue again, an ideal feature for a lightweight shoe designed for fast paces that require a secure lockdown—and the ES4 delivers just that!

Saucony Endorphin Speed 4 Tongue: gusset type
Test results
Endorphin Speed 4 Both sides (semi)

Comfort

Tongue padding

The tongue padding is kept to a minimal 2.0 mm, part of the effort to maintain a low weight.

Saucony Endorphin Speed 4 tongue

Therefore, we advise caution when tightening the laces, particularly for longer runs, to prevent any lace bite.

Saucony Endorphin Speed 4 Tongue padding
Test results
Endorphin Speed 4 2.0 mm
Average 5.6 mm
Compared to 302 running shoes
Number of shoes
0.5 mm
Tongue padding
14.2 mm

Heel tab

In line with recent Saucony design trends, we didn't anticipate a heel tab, and indeed, there wasn't one to be found.

Saucony Endorphin Speed 4 Heel tab
Test results
Endorphin Speed 4 None

Removable insole

The insole is removable and features a very standard shape, allowing for easy insertion of third-party sockliners without any issues. Also, for runners with larger feet, opting for a thinner insole can also increase the shoe's overall internal volume.

Saucony Endorphin Speed 4 Removable insole
Test results
Endorphin Speed 4 Yes

Misc

Reflective elements

We're always impressed when brands prioritise runner safety. Thus, discovering reflective elements on the Endorphin Speed 4 was a fantastic highlight, enhancing visibility and protection.

Test results
Endorphin Speed 4 Yes