Saucony Endorphin Speed 6 Review: An Icon That Lost Its Edge

Introduction

Few running shoes carry as much history as the Saucony Endorphin Speed. Around 2020 and 2021, the original and the Speed 2 helped define the super trainer category: a plastic plate instead of carbon, softer and more flexible than a race shoe, and versatile enough to double as a daily trainer and a first race shoe. It became a default recommendation at local running stores, the shoe you walked out with when you asked for a speed trainer.

The sixth entry arrives with Power Run PBX foam, an added 2 mm of stack in the heel, and a widened heel geometry. On paper it looks like a sensible evolution. In practice, after a full 10-mile test run at everyday paces, this generation left us genuinely disappointed. It is not a failed product, but it is a clear step back for a franchise that used to feel special.

Key Updates in This Version

Saucony calls the midsole Power Run PBX, described as softer, lighter, and bouncier than before. Pressing into it by hand, though, it feels very close to the previous Power Run PB: firm, dense, and not obviously improved. The X appears to signal a minor change rather than a revolution. The heel has also been widened and beefed up, borrowing geometry cues from the Endorphin Elite line, and the extra 2 mm of stack should add some underfoot protection.

The classic speed roll geometry is still present in theory. This was one of the first training shoes to bring an aggressive rocker to the masses, delivering a smooth heel-to-midfoot transition and clean toe-off. The upper remains largely unchanged: lightweight mesh, a moderately padded tongue, and good padding around the heel. Once an Endorphin Speed, always an Endorphin Speed, at least visually.

Specs and Weight

At 243 g in our test size, the Speed 6 sits right back where the Speed 2 was (244.5 g), lighter than the outgoing Speed 5 (258 g) and lighter than the Adidas Evo SL (261 g), though heavier than the New Balance SC Rebel at 224 g. For a performance trainer, that weight is competitive and matters moderately, especially if you have aspirations toward speed.

Outsole coverage is good, with plenty of exposed foam underneath. The chunky, widened heel is the most noticeable construction change.

Who This Product Is For

Historically, this is a shoe built around the 7-minute mile. It targets runners training for their first half marathon or marathon, or athletic newcomers who run that pace as their everyday speed. On this test’s 10-mile run at a 7:37 average pace, however, the shoe simply did not feel good at that pace. The foam felt stiff, blocky, and slow to compress, with little bounce and no encouragement to turn the legs over quickly.

It also lost the fun factor that made earlier versions lovable: the quirky softness, the fantastic geometry, the comfort. The forefoot lacks protection, the ride feels choppy rather than smooth, and the step-in feel is stiff and uninviting. If earlier Endorphin Speeds were gentle, smooth, and comfort-oriented, this one combines the worst traits of generations three through five into a single shoe.

Things to Consider Before Buying

The market has moved. Non-plated super trainers like the Evo SL, Superblast, Mega Blast, and Dino Fish now offer lighter, livelier rides with far more comfort, and the SC Rebel shows how a plated trainer can evolve with a genuinely new foam. At a $175 price point, the Speed 6 competes against shoes that simply deliver more.

There are positives: stability is genuinely good, and the fit is true in our tester’s usual size. Some buyers may find the firm, stable ride acceptable, and it is possible this pre-release sample pair does not represent the final production feel. But in its current form, we would point most buyers toward the SC Rebel, Mega Blast, Sonic Blast, or a non-plated super trainer for daily miles instead.

Buying Advice

Skip this one if you are shopping in this category today. If you already own it and find it comfortable, there is nothing structurally wrong with running in it; plenty of people will. But for a high-performance trainer, the alternatives offer better cushioning, better bounce, and better value. Our hope for the Endorphin Speed 7 is a real foam change, because this franchise deserves better than a slow chop.

Conclusion

The Endorphin Speed 6 is a C-to-C-minus shoe: runnable, stable, and forgettable at best. For a line that once defined an entire category the way the Vaporfly defined race day, that is a hard verdict to write, but the right one to share.