Enzymes — HTS 3507
Enzymes; prepared enzymes not elsewhere specified or included
Chapter 35 › Heading 3507
2026 HTS Rev 19 Synced Rules verified Operational
Written to help non-specialists understand this page. Rates, dates, and legal facts come from the official records above and on the linked source.
HTS heading 3507 covers enzymes and prepared enzyme products that are not more specifically classified elsewhere in the tariff. An enzyme is a biological substance that speeds up a chemical reaction. The heading can include individual enzymes, enzyme mixtures, and prepared enzyme products used in areas such as food processing, detergents, manufacturing, or laboratory work.
Heading 3507 is only a 4-digit category, not the complete classification. To reach the correct 8-digit HTSUS code, first identify the product’s enzyme or enzyme preparation and then follow the heading’s subheadings and tariff descriptions. The specific code is usually narrowed by the enzyme’s name or type, whether it is a mixture or preparation, and any stated “other” category. Review the full legal text, including section and chapter notes, because a product may be classified elsewhere if another heading describes it more specifically.
What to check
- Confirm the product’s technical identity: enzyme name, source, activity, formulation, and intended use.
- Check whether the item is a single enzyme, a mixture, or a prepared product, and compare those facts with the 8-digit subheading descriptions.
- Read the relevant HTSUS section and chapter notes, including exclusions that may move the product to another heading.
- Use the product’s safety data sheet, specification sheet, certificate of analysis, and ingredient or formulation records to support classification.
- If the wording remains ambiguous, ask a licensed customs broker or seek a formal classification ruling from U.S. Customs and Border Protection.
HTS heading 3507 summary
Enzymes is a 4-digit product category containing 1 published product-code lines in this snapshot. A heading does not carry one universal duty rate; classification must be narrowed to the line matching the product facts.
How to find your code in this category
A heading is a product category. To get the exact duty, narrow from this 4-digit heading to a sub-category (usually by material), then open the 8-digit code that matches your product.
Open any code in the tables below to see its exact duty rate, a duty calculator (enter your shipment value → estimated duty and landed cost), the rate-change history chart, and the country-by-country breakdown (including Section 301/232 add-on duties).
Why you have to click in: a single category can contain products with very different duties. The rate depends on the specific product — its material and construction — and on the country of origin, and those only get pinned down at the 8-digit code level. That is why this page points you to codes instead of showing one rate for the whole category.
Sub-categories
| Code | Description |
|---|---|
| 3507.90 | Other |
Product codes & duty rates
👇 Each row is a specific product code — click a blue code to open its full page with exact duty rates by country, the rate-history chart, and a duty calculator. 👉
| Code | Description | General (MFN) | Special | Column 2 |
|---|---|---|---|---|
| 3507.10.00.00 👉 | Rennet and concentrates thereof | Free | — | Free |
"Special" shows the free-trade-agreement rate; open a code to see exactly which countries qualify.
Common questions
What products fall under HTS heading 3507?
Enzymes; prepared enzymes not elsewhere specified or included. To classify a specific item you must pick the matching sub-category and 8-digit code above; the right choice usually depends on the material and construction of the product.
How do I choose the right code within this category?
Start from the sub-categories (typically divided by material—for example cotton versus man-made fibers), then open the active 8- or 10-digit code that matches the product. When unsure, a licensed customs broker or a CBP binding ruling can confirm the classification.
Reference information only, not customs, legal, or classification advice. Confirm the current code and rate against the official HTS before you import.