Old Navy · Sports Performance Undergarments
Old Navy Men's Go-Dry Cool Performance Boxer- Brief Underwear 3-Pack
Performance underwear likely uses water-repellent coating; Gap discloses nothing about PFAS.
Go-Dry labeling indicates a moisture management coating typical in athletic underwear. Old Navy provides no PFAS transparency, leaving treatment chemistry unknown.
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Material
Nylon/polyester blend with moisture-wicking treatment
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What’s concerning
Category baseline
The starting point for this type of product, before anything specific to this product is counted.
No PFAS disclosure
No public statement from the brand about PFAS in this product.
Waterproof / stain-resistant treatment
Water-repellent coating treatments have historically used PFAS.
Formaldehyde / VOCs
Moisture-wicking treatments sometimes rely on formaldehyde-based cross-linking resins to fix hydrophobic or hydrophilic polymers to fiber surfaces. Old Navy does not disclose the finish chemistry, so presence cannot be ruled out. Exposure is typically minimal after initial laundering but can cause skin irritation in sensitive individuals.
Source, ATSDR ↗Antimony in polyester
Polyester is synthesized using antimony trioxide as a catalyst; residual antimony may remain in finished fiber at trace levels (typically <0.1% but not guaranteed). Migration to skin under sweat conditions is very low but not independently tested for this product. No regulatory limit applies to antimony in textiles in most jurisdictions.
Microfiber shedding during laundering
Synthetic blends like nylon/polyester shed microfibers during every wash cycle, contributing to microplastic pollution. This is not a direct health risk to the wearer but a lifecycle concern; damage to product (pilling, wear) accelerates shedding.
Skin sensitization from undisclosed chemical treatments
Without disclosure of the moisture-wicking treatment agents, potential skin contact with residual surfactants, catalysts, or cross-linking compounds cannot be fully assessed. Incidence is rare but documented in some users of performance athletic wear; discontinuation and laundering typically resolve symptoms.
What’s reassuring
Azo dyes and synthetic dye residues
No specific recalls or reported incidents for Old Navy boxer-briefs involving azo dyes. Nylon and polyester typically accept synthetic dyes without prohibited carcinogenic azo compounds, but pre-production testing data is not publicly available for this product line.
The full breakdown
What it's made of and why it matters
This product is a nylon/polyester blend engineered with a moisture-wicking treatment to pull sweat away from skin. Performance underwear blends typically use synthetic fibers because natural fibers (cotton, wool) absorb rather than repel moisture, making them uncomfortable during activity. The treatment chemistry is not disclosed by Old Navy or Gap, which is the primary concern; moisture-wicking finishes in this category often rely on water-repellent coating (water-repellent coating) coatings that may contain fluorinated compounds (addressed separately as PFAS) or other surfactants.
The brand's record and disclosure
Gap Inc. has not published a PFAS disclosure policy or commitment to phasing out fluorinated finishes in apparel as of available public records. The company does not certify this product to recognized textile safety standards (Oeko-Tex, GOTS, Bluesign). Gap's broader sustainability reporting focuses on labor and environmental impact of manufacturing but does not address chemical composition of performance treatments. This silence on treatment chemistry is standard for the mass-market athletic basics segment but represents a gap in consumer transparency.
How it compares in its category
Performance boxer-briefs in the budget-to-mid segment ($15-25 per pack) rarely disclose treatment chemistry; this product is typical in that respect. Premium alternatives (Patagonia, Allbirds, some brands certified to Oeko-Tex) explicitly limit or eliminate fluorinated water-repellent coating finishes and publish material sourcing. Gap's offering is competitively priced and functionally adequate for everyday moisture-wicking but offers less chemical transparency than certified competitors. For the price point, transparency expectation is lower than premium brands, but not zero.
If you buy it
Wash in warm water without fabric softener, which degrades moisture-wicking performance and can trap chemicals. Avoid high heat drying (tumble dry low or air dry); heat can accelerate breakdown of synthetic coatings and increase potential leaching. Replace when elastic degrades or odor persists after washing, typically 1-2 years of regular use. If you experience skin irritation (rare but possible with formaldehyde-based resin finishes), discontinue and rinse thoroughly before wearing.
What we don’t know
- Basis
- Model estimate, 45% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Old Navy has made none
Formulations change between production runs, so check the current label. How we grade.
Better-graded alternatives in Sports Performance Undergarments
Reebok
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nylon, spandex, cotton blend
Formaldehyde / VOCs
Limited concern
Azo dyes
Limited concern
Elastomer degradation (spandex breakdown)
Limited concern
Lower concern with no known PFAS triggers identified.
⚠Starting grade for this product type
Reebok
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nylon/elastane blend, seamless knit
Elastane degradation and skin contact
Limited concern
Basic seamless intimate wear lacks water-resistant coatings.
⚠Starting grade for this product type
Reebok
Men's Featherweight Performance Boxer Briefs
polyester and elastane blend
Antimony in polyester synthesis
Limited concern
Microplastic shedding during washing
Limited concern
Polyester-elastane blend with no coating or water-repellent finish on record.
⚠Starting grade for this product type
More sports performance undergarments 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.