Does Hydro Flask Wide Mouth have microplastics?

Bottles & drinkware

Moderate exposure

Some plastic contact, but limited by material, temperature or contact time. Reasonable as a default.

Grade C58% confidenceStainless steel body with a polypropylene flex cap

0 · no plastic contact100 · constant contact

Two numbers, not one. Exposure is how much plastic contact this involves. Confidence is how much anyone has actually measured. How we score

The short answer

Low, and mostly a question about which lid you bought. The standard flex cap is a simple screw closure with one gasket, which is about as little polymer as a leak-proof reusable can have. Straw lids move it up.

Plastic lid or cap format profile

Made ofStainless steel

Why Hydro Flask Wide Mouth scores 27

Steel interior — the body contributes nothing at all
One polypropylene cap with a single gasket, screwed on and off several times a day
Thread abrasion is the dominant mechanism and it scales with how often you open it
Swapping to the straw lid roughly doubles the polymer in contact with the water

Where the 27 comes from

Five components, added. The page renders the parts rather than a stored total, so the number cannot disagree with the reasoning behind it.

Packaging contact: 6 / 30
Use conditions: 12 / 25
Measured release: 4 / 25
Polymer behaviour: 5 / 10
Processing: 0 / 10

Total exposure27 / 100

What we don't know

Unmeasured, like every bottle closure. Also unmeasured: whether the powder-coat exterior matters, which it should not since it never contacts the contents, but nobody has checked.

This section is on every page in the database, including the ones where the answer is comfortable. How evidence grades work →

Better options

Ordered by how much they change, not by how much they cost.

All-steel lid, if the brand offers one

removes the last polymer contact face

Glass bottle

if you do not need the insulation

Check the one in your hand

This page scores Hydro Flask Wide Mouth as a product. Formulations, packaging and suppliers change, and the specific item you own has its own condition — a scratched pan and a new one are not the same object. Scan yours for a score built from what is actually in front of you.

Scan my bottles & drinkware

Sources behind this score

Each with the finding we use it for and the limitation that finding carries — because a study quoted without its boundaries is how this subject got so noisy.

peer-reviewed2020
Sobhani 2020 — Simply tearing, cutting or twisting open plastic packaging generates microplastics at the opening — 10–30 nanograms per 300 cm of tear.
Limitation: Mass, not particle count, and it does not follow whether those particles land in the food. It is the reason cap and seal design belongs in an exposure score at all.
peer-reviewed2022
Zangmeister 2022 (NIST) — Nylon bags, LDPE food-storage bags and similar single-use plastics shed trillions of sub-100 nm particles per litre in ordinary contact with water.
Limitation: Deionised water at controlled temperature. Nanoparticle counts are inherently large numbers; the study is about their existence and quantity, not their fate in the body.

Frequently Asked Questions

Does Hydro Flask Wide Mouth have microplastics?

How was the Hydro Flask Wide Mouth score of 27 calculated?

Five components, added: packaging contact 6/30, use conditions 12/25, measured release 4/25, polymer behaviour 5/10 and processing 0/10. The page computes the total from those parts rather than storing it, so the number cannot drift from the reasoning.

Is Hydro Flask Wide Mouth safe?

The score does not answer that and we will not pretend it does. It measures plastic contact, which is a physical property of the product. Whether a given level of exposure affects health is an open question — the FDA states the current evidence does not demonstrate a risk at the levels found in food, while research such as the 2024 NEJM plaque study gives real reasons to keep studying it. Both are true at once.

Why is the confidence only 58%?

No measurement of the product or its category exists. The score rests on published evidence about how this polymer behaves under these conditions — heat, abrasion, contact time, fat content. Because this is not a direct measurement of the product itself, the score should be read as a well-reasoned estimate that could move if someone tests it.