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PlasticsResin code 7Is a plastic

Is Tritan copolyester plastic?

The short answer

Yes, Tritan is a plastic — a copolyester made by Eastman. It is genuinely BPA-free, which is a claim about a leached chemical and not about particle shedding. Those are two different questions and they get conflated constantly.

Also called: tritan, copolyester, is tritan plastic, tritan bpa free

How it behaves

The four conditions that decide whether a material is a problem in practice rather than in principle.

Heat
Moderate

Does normal domestic heat degrade it?

Abrasion
Moderate

Do scratching, cutting or flexing generate particles?

Fatty food
Low

Does fat pull additives or particles out of it?

Acidic food
Low

Do acidic contents attack the surface?

Evidence grade CGrade C — polymer evidence

What Tritan copolyester actually is

A copolyester engineered as a replacement for polycarbonate in reusable bottles and blender jugs, prized for being glass-clear, impact-resistant and dishwasher-durable. It carries resin code 7, the "other" bucket, which is why it is often mistaken for a mystery plastic. It is not a mystery — it is a well-characterised copolyester with no bisphenol A in the formulation.

Where you find it

Reusable water bottlesBlender jugsBaby bottlesFood containersShaker cups

What Tritan copolyester releases, and when

Nobody has measured particle release from Tritan. That is the honest position and it is worth stating clearly because the marketing around this material is unusually confident. What we can say structurally: it is a polymer wall in continuous contact with the contents, it is designed to be reused for years, and mechanical stress raises release from plastic bottles generally. The absence of BPA does not speak to any of that.

Graded C. 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. How evidence grades work →

How to tell you're holding it

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Stainless steel

No microplastics at all — steel is a metal and cannot shed a polymer. The catch is the parts around it: a steel bottle is only as clean as its lid, and the lid is almost always plastic.

Glass

No polymer touches the contents, which makes glass the cleanest widely available food material. Worth knowing: glass bottles measured around 50 particles per litre in the one study that compared formats — from the cap and the filling line, not the glass.

Products we've scored involving Tritan copolyester

Each with its own 0–100 exposure score, evidence grade and sources.

49

Nalgene Wide Mouth bottle

Tritan copolyester bottle with a polypropylene cap

Moderate

Grade C · 60%

49

Blender with a plastic jug

Tritan copolyester or polycarbonate jug

Moderate

Grade C · 56%

49

Plastic sippy cup

Polypropylene or Tritan cup with a silicone or polypropylene valve

Moderate

Grade C · 60%

Not sure what yours is made of?

Most products never state the polymer, and a resin code on the base only tells you about the body — not the lid, the liner or the seal. Scan the item and the app identifies the materials in it, then scores them together.

Identify what mine is made of

Sources

  1. Winkler 2019 — Refilling and mechanically stressing PET bottles measurably increased particle release compared with first use.

    Limitation: A laboratory stress protocol rather than observed household reuse. It establishes direction — reuse of single-use PET makes things worse — more firmly than magnitude.

  2. 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

Is Tritan copolyester a plastic?

Yes, Tritan is a plastic — a copolyester made by Eastman. It is genuinely BPA-free, which is a claim about a leached chemical and not about particle shedding. Those are two different questions and they get conflated constantly.

Does Tritan copolyester release microplastics?

Nobody has measured particle release from Tritan. That is the honest position and it is worth stating clearly because the marketing around this material is unusually confident. What we can say structurally: it is a polymer wall in continuous contact with the contents, it is designed to be reused for years, and mechanical stress raises release from plastic bottles generally. The absence of BPA does not speak to any of that.

What should I use instead of Tritan copolyester?

Stainless steel, Glass. No microplastics at all — steel is a metal and cannot shed a polymer. The catch is the parts around it: a steel bottle is only as clean as its lid, and the lid is almost always plastic.

How do I know if something is made of Tritan copolyester?

A 7 in the triangle, usually with "Tritan" moulded nearby. Glass-clear like polycarbonate but noticeably lighter than glass. Marketed heavily as BPA-free on the packaging. Standard on Nalgene, most blender jugs and many shaker bottles.

Related materials

Stainless steel

No microplastics at all — steel is a metal and cannot shed a polymer. The catch is the parts around it: a steel bottle is only as clean as its lid, and the lid is almost always plastic.

Glass

No polymer touches the contents, which makes glass the cleanest widely available food material. Worth knowing: glass bottles measured around 50 particles per litre in the one study that compared formats — from the cap and the filling line, not the glass.

Polypropylene

#5

Yes, polypropylene is a plastic — resin code 5, and one of the more thermally stable food plastics. That stability is exactly why it ends up in the containers people microwave, which is where its problems start.

Polyethylene

Yes. Polyethylene is the most-produced plastic on earth and the polymer most often detected in human tissue — it was the plastic found in 58.4% of carotid plaques in the 2024 NEJM study.

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