S'ip by S'well Travel Mug vs Stainless Steel King Travel Mug: which is safer?

THERMOS Stainless Steel King Travel Mug is our pick: better on PFAS and on the overall hazard picture.

S'ip by S'well Travel Mug

S'well

S'ip by S'well Travel Mug

PFAS grade

Excellent 85/100

Overall grade

Good 73/100

Verdict

Buy

Hazard flags

⚑ 3

Material

Stainless steel with plastic lid components

Confidence

72%

PossiblePlastic lid polymer leaching (BPA/BPS, phthalates)

PossibleBacterial growth in lid crevices and seals

PossibleMicroplastic shedding from lid wear

Our pick

THERMOS Stainless Steel King Travel Mug

Thermos

Stainless Steel King Travel Mug

PFAS grade

Excellent 95/100

Overall grade

Excellent 83/100

Verdict

Buy

Hazard flags

⚑ 3

Material

Stainless steel interior and exterior, plastic lid

Confidence

82%

PossiblePlastic lid polymer degradation

PossibleGasket/seal material composition

PossibleThermal shock stress on seals

Where these two actually differ

  • We flag Plastic lid polymer leaching (BPA/BPS, phthalates), Bacterial growth in lid crevices and seals and Microplastic shedding from lid wear on the S'well and not on the Thermos.
  • We flag Plastic lid polymer degradation, Gasket/seal material composition and Thermal shock stress on seals on the Thermos and not on the S'well.
  • The S'well is Stainless steel with plastic lid components where the Thermos is Stainless steel interior and exterior, plastic lid, which is most of the difference in these two grades.

Both products run through the same public rubric: materials, coatings, brand disclosure, lab findings, and recalls, plus a beyond-PFAS hazard analysis. Grades are model-based estimates, not lab tests. How grades work →

More insulated travel mugs: see the full ranking