Analysis
HTS 2937.90.40 covers l-Thyroxine (Levothyroxine), sodium under heading 2937 (hormones, prostaglandins, thromboxanes and leukotrienes, natural or reproduced by…).
There is no general-rate duty on this line, which puts it with roughly 26% of the 1050 tariff lines in chapter 29 that are also free. Free here means free of the base duty only: origin-specific Chapter 99 duties such as Section 301 can still be owed.
Census statistics map these goods to NAICS 325412 (Pharmaceutical Preparation Manufacturing), an industry of 1,436 US establishments employing 170,029 people, the industry a domestic producer of these goods reports under.
All 5 neighbouring lines carry the same duty-free rate, so a borderline choice between them changes the statistics reported, not the duty paid.
Every edition we compared, from Jan 2023 to Oct 2026 (Rev. 22), shows the same general rate of Free.
Neighbouring lines
| Line | Description | General rate |
|---|---|---|
| 2937.90.05 | Catecholamine hormones, their derivatives and structural analogues: epinephrine | Free |
| 2937.90.10 | Epinephrine hydrochloride | Free |
| 2937.90.20 | Other: other | Free |
| 2937.90.45 | Amino-acid derivatives: other | Free |
| 2937.90.90 | Other: other | Free |