S'well · Insulated Travel Mugs
S'well Mug Pink
Low concern. Stainless steel construction unlikely to hold PFAS.
S'well's stainless steel vacuum design needs no PFAS-containing treatments. The brand stays quiet on PFAS but the material itself carries minimal risk.
We flunk more products than we pass. This one earned its grade. How we grade
Material
Stainless steel double-wall vacuum insulated
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What’s concerning
Category baseline
PFAS exposure happens more often with clothing products.
No PFAS disclosure
The company has not publicly discussed PFAS in this product.
Nickel leaching from stainless steel
18/8 stainless contains 8% nickel. While FDA-approved for food contact, prolonged exposure to acidic liquids (citrus, vinegar, wine) can release trace nickel; risk is low for most users but relevant for those with nickel sensitivity or those who store acidic beverages for hours daily.
Vacuum seal degradation
Repeated temperature cycling or impact can compromise the seal integrity, allowing ambient air or moisture to enter the gap between walls. This does not pose acute toxicity risk but may enable bacterial growth in the insulation cavity if water enters, rendering the product unusable.
Lid or seal material hazards
S'well mugs typically include a plastic or silicone lid (product imagery suggests plastic). S'well does not publicly disclose lid material composition or BPA/phthalate testing; typical plastic lids may contain low levels of these compounds, especially if heated in dishwashers or with hot liquids.
What’s reassuring
Safe base material
Made from ceramic, mineral, or natural fiber with no PFAS risk.
Heavy metals
No recalls or test data on record for S'well mugs showing lead, cadmium, or other heavy metals. Stainless steel purchased to food-grade standards should be free of these; however, S'well does not publicly certify third-party heavy metal testing.
Source: FDA ↗Coating or finish toxins
The product uses no interior enamel, ceramic glaze, or polymer coating, eliminating the primary pathways for lead, cadmium, or bisphenol leaching seen in coated drinkware. The exterior finish is bare metal or minor aesthetic treatment not in contact with beverages.
The full breakdown
What it's made of and why it matters
The S'well Mug is constructed from 18/8 stainless steel (also called 304 stainless), a food-grade alloy with 18% chromium and 8% nickel that resists corrosion and does not leach into beverages under normal use. The double-wall vacuum insulation contains air or inert gas between layers, eliminating the need for plastic liners or foam that would introduce leaching risk. The interior and exterior are both bare stainless steel with no ceramic coating, enamel, or polymer finish that could degrade over time.
The brand's record and disclosure
S'well does not publicly disclose detailed material sourcing, coating processes, or third-party testing results for this product. The brand has not faced documented recalls or safety complaints specific to the mug line. Their website emphasizes durability and insulation performance but offers no published certifications (e.g., FDA compliance statements, BPA-free claims, or heavy metal testing) that would strengthen confidence in material purity.
How it compares in its category
Stainless steel mugs occupy a safer segment than ceramic-lined, polymer-coated, or plastic-core alternatives. Most competitors in this price range either use lower-grade stainless steel, plastic liners, or ceramic coatings that introduce leaching or degradation risk. S'well's minimalist design (no interior coating) is a material advantage, though the brand does not independently verify composition or test for trace heavy metals the way some premium European makers do.
If you buy it
Wash by hand with mild soap rather than dishwasher to avoid potential discoloration or minor pitting of the finish over years of use. Do not allow acidic or very hot liquids to sit for extended periods, as stainless steel can develop a faint metallic taste over time with corrosive beverages (rare but documented with vinegar or citric acid). The vacuum seal is permanent; if insulation fails (water or condensation inside), replacement is the only option. Store dry to prevent any mineral buildup at seams.
What we don’t know
- Basis
- Model estimate, 78% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- S'well has made none
Formulations change between production runs, so check the current label. How we grade.
Safer alternatives in Insulated Travel Mugs
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Gasket/seal material composition
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Thermos
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Thermos
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Nickel leaching from stainless steel
Limited concern
Chromium leaching from stainless steel
Limited concern
Thermal shock and seal degradation
Moderate concern
Lower concern; stainless steel mug has no water-repellent coating.
✓Bare metal or glass, no coating at all
More insulated travel mugs 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.