Ask the advisor

TPU foam in running shoes

Thermoplastic polyurethane is the historic durability champion of running shoe foams. The most famous example — Adidas Boost — used BASF's Infinergy expanded TPU and ran for the better part of a decade as the bounciest commodity midsole in the category. TPU nearly disappeared from running shoes when supercritical EVA and PEBA arrived, but the chemistry is having a quiet revival in 2025–26.

What TPU actually is

Thermoplastic polyurethane is a block copolymer made from alternating "hard" segments (typically methylene diphenyl diisocyanate plus a short-chain diol) and "soft" segments (a longer-chain polyether or polyester polyol). The hard segments give the polymer its strength and abrasion resistance; the soft segments give it elasticity. By tuning the ratio of hard to soft segments, the same chemistry can yield anything from a rigid plastic (think phone cases) to a soft elastomer (think running shoe midsoles).

The version that landed in running shoes was BASF's Infinergy, first commercialized as Adidas Boost in 2013. Infinergy is an expanded TPU (eTPU) — discrete TPU pellets are foamed individually using supercritical CO₂, producing thousands of small foamed beads that are then molded together under heat and pressure. The bead structure is what gave Boost its distinctive look (visible spherical foam under the strobel) and its distinctive ride: high rebound, very high durability, but heavy.

Two TPU relatives sit close by. Aliphatic TPU (A-TPU) — a UV-stable grade — has become a premium racing super-foam in its own right (ASICS FF Leap, Puma NITRO Elite), a different story from the durable commodity TPU on this page, so it gets its own A-TPU page. Within the durable-TPU family the variants you'll see are beaded TPU (the original Infinergy-style process, used by Saucony in older PWRRUN+) and supercritical eTPU (a refined process producing smaller, more uniform cells than the original beaded approach — in the new Saucony Ride 19's PWRRUN+).

Related: Most TPU midsoles in 2026 are foamed via the same supercritical process described on the Supercritical foams page. The chemistry is the polymer; the foaming step is a separate axis.

Why TPU matters for runners

The headline TPU advantage is durability. TPU midsoles routinely go 600–800 miles without measurable ride-feel degradation; well-formulated EVA goes 400–500; PEBA goes 200–300. For runners who train 50+ mpw on one or two pairs per year, that is the most important distinction in the category.

The second TPU advantage is consistent rebound across temperatures. TPU's mechanical properties are unusually flat across the typical-temperature range a runner encounters (5–25°C). EVA stiffens measurably in the cold; PEBA stiffens less but still measurably. TPU feels the same on a 0°C winter morning as it does on a 30°C summer afternoon. For runners in cold climates this matters more than the rebound figures suggest.

The honest tradeoffs: TPU is dense. The base polymer's specific gravity is around 1.20 g/cm³, vs 0.95 for EVA and well below that for PEBA. Foamed at the same density (gas content), a TPU midsole is perceptibly heavier than an EVA midsole at the same stack height. That's why TPU's mainstream era ended when the lighter foams arrived — Adidas itself moved their racing line to PEBA (Lightstrike Pro) and their dailies to lighter chemistries.

The 2026 case for TPU is targeted, not universal. The Run Testers and Doctors of Running both observe that runners who chew through foam (heavier runners, higher-mileage runners, runners who break down typical EVA in 250 miles) routinely report TPU midsoles going 2–3× the typical lifespan. For that demographic the weight penalty is worth it; for the lightweight tempo runner it isn't.

Featured shoes built on TPU

Saucony Ride 19

PWRRUN+ (supercritical eTPU)

Supercritical eTPU as a daily-trainer midsole. Saucony reformulated PWRRUN+ to use a supercritical-foamed expanded TPU — same chemistry family as the original Adidas Boost. Doctors of Running notes the new Ride keeps the legendary durability the Ride line has always had and adds back the bounce TPU is famous for.

Mizuno Neo Vista 2

Mizuno Enerzy NXT (supercritical TPU + EVA)

Supercritical TPU + EVA dual-foam in a max-cushion daily. Mizuno's Enerzy NXT in the Neo Vista 2 layers supercritical TPU on a softer EVA base. Believe in the Run treats it as one of the most underrated daily trainers of 2026 — TPU's energy return without TPU's traditional weight penalty.

New Balance Fresh Foam X More 6

Fresh Foam X (EVA+TPU blend)

TPU as a blend partner in a max-cushion EVA midsole. The More v6's Fresh Foam X is an EVA + TPU blend; New Balance uses TPU at low percentages to add resilience to the EVA matrix. Run Testers describes the More v6 as the cushiest shoe in the catalog that still feels lively underfoot.

Saucony Ride 18

PWRRUN+ (beaded TPU)

Beaded TPU as a previous-generation reference point. The Ride 18's PWRRUN+ uses the older beaded-TPU process — adjacent to but distinct from the new supercritical version. Useful as the comparison point for the Ride 19 jump; Kofuzi describes the difference as larger than a typical year-over-year update.

None of the shoes on this page use TPU as the entire midsole the way Adidas Boost did — current durable-TPU shoes use it as a blend partner, an insert layer, or a sockliner paired with a lighter primary foam. (The full-midsole aliphatic-TPU racers — Puma's Fast-R, ASICS's Metaspeed line — live on the A-TPU page.)

Every shoe in the catalog using TPU

19 shoes. Includes pure TPU midsoles, supercritical eTPU, beaded TPU, Nike's TPE-based trainer ZoomX (the Vomero line — grouped here as the nearest fit in the thermoplastic-elastomer family, since it's not the Pebax used in Nike's racers), and dual-foam constructions where TPU is one of the layers. (Aliphatic A-TPU racers are on the A-TPU page.)

Sources

Methodology. Chemistry sourced from manufacturer technical data and standard polymer-chemistry references. Shoe-level commentary is summarized from named reviewers (Doctors of Running, Believe in the Run, The Run Testers, Kofuzi, EDDBUD) — every shoe page linked above carries the original verdicts with source links. Never sponsored, never paid placement.