Spenco · Synthetic Athletic Insoles & Orthotics
Spenco Polysorb Cross Trainer Insole
Insole foam likely PFAS-free, but no brand transparency.
Spenco Polysorb is a proprietary foam cushioning material with no known PFAS concerns reported. Brand provides no PFAS disclosure, leaving uncertainty despite foam's inherent lower risk.
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Material
Polysorb foam cushioning, composition not fully disclosed
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
Why this grade
Safe base material
Made from a material with no inherent PFAS use (ceramic, mineral, or natural fiber).
Category baseline
clothing is a category where PFAS exposure is more common.
No PFAS disclosure
No public statement about PFAS in this product.
The full breakdown
What it's made of and why it matters
Spenco Polysorb insoles use a proprietary closed-cell foam cushioning material designed for shock absorption in athletic shoes. The exact chemical composition is not fully disclosed by Spenco, which is typical in the insole industry but limits independent verification of contaminants. Polysorb itself is engineered to be chemically inert during normal use and does not contain known problematic additives like phthalates or BPA that are common in softer plastics. The foam is bonded to a fabric covering, usually polyester or nylon, which carries minor formaldehyde resin and azo dye risks standard to all textiles.
The brand's record and disclosure
Spenco, a subsidiary of Implus Corporation, manufactures orthopedic and sports medicine products and maintains a reputation for foot-care products without major recalls related to chemical contamination. The brand does not publicly disclose PFAS content or provide third-party testing results for insole materials, which aligns with industry norm but reflects lack of transparency rather than confirmed safety. No established controversies regarding heavy metals, formaldehyde, or allergen contamination in their insole lines have been documented in public health databases or consumer safety reports.
How it compares in its category
Polysorb foam insoles are mid-range in the athletic insole market; competitors using similar closed-cell foam (e.g., Dr. Scholl's) or competing materials (gel, cork, ethylene vinyl acetate) carry comparable or slightly lower documented chemical risk profiles. Premium insoles from brands like Superfeet and Powerstep often provide more material transparency and third-party certifications, though chemical hazard levels are similar. Budget insoles sometimes use softer plastics with higher phthalate or plasticizer risk, making Polysorb a safer choice relative to cheaper alternatives.
If you buy it
Replace insoles every 6 to 12 months depending on use intensity, as foam degradation can release particles; do not expose to sustained heat above 140 degrees Fahrenheit (60 Celsius), as foam may soften or off-gas. Wash the fabric cover periodically with mild soap and cool water; air-dry to avoid accelerating breakdown. Store in a cool, dry location away from direct sunlight to minimize oxidative degradation of the foam matrix. If you develop skin irritation or notice a chemical odor when first opening the product, air the insoles for 24 hours before use.
Beyond PFAS: other things we checked
Established hazard classes for this product type, assessed from public information. These never change the PFAS grade; a Likely flag caps the Verdict at “Buy with care.”
Formaldehyde resins in textile covering
The polyester or nylon fabric bonded to Polysorb foam may contain formaldehyde-based resins used in finishing and coating processes. Dermal contact risk is low for intact fabric, but risk increases if fabric degrades or is in prolonged contact with perspiration over months.
Azo dyes in fabric
Colored polyester or nylon covers may use azo dyes, which can degrade under sweat and microbial action in the warm, moist shoe environment. Risk of sensitization or contact dermatitis is low but documented in sensitive individuals, particularly if the insole fabric is in direct contact with broken skin.
Foam degradation and microparticle release
Polyurethane and polyolefin foams used in insoles can break down over 6 to 12 months of use, potentially shedding fine particles into the shoe and respiratory zone. This is a mechanical rather than chemical hazard, but particle inhalation in poorly ventilated shoes or during vigorous activity is a minor documented concern.
Antimony in polyester components
Polyester textiles sometimes contain antimony as a catalyst residue from production. No public recalls or test results for Spenco insoles indicate antimony contamination, and levels in intact polyester fabric are typically considered negligible dermal risk.
Chemical off-gassing (VOCs) from adhesives
Adhesives bonding the foam to the fabric cover may release volatile organic compounds (VOCs) during the first few days to weeks of use, particularly in a warm shoe environment. Odor is typically the only sensory indicator; respiratory or systemic toxicity from this source is not documented for this product class.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 62% confidence. It is not a lab result.
No independent PFAS lab test is on record for this exact product. A lab test could move the score in either direction.
The brand has not made a specific, verifiable PFAS-free statement, so part of this score reflects that missing disclosure rather than a confirmed material.
Formulations and coatings change between production runs. Always check the current label before buying.
More synthetic athletic insoles & orthotics grades
How we score: every product runs through the same public 0–100 rubric based on materials, coatings, brand disclosure, lab findings, and recalls. See the full methodology → Spotted a mistake? Report an error.