Suzhou Pharmaceutical Technology Co., Ltd. (China) supplies Levothyroxine Sodium API CAS 55-03-8 for pharmaceutical B2B procurement — COA, MSDS, and technical documentation available on request.
> Levothyroxine Sodium API — Overview
Levothyroxine Sodium (CAS: 55-03-8, also known as L-thyroxine sodium, thyroxine sodium, T4 sodium salt, levotiroxina sódica, Synthroid active ingredient, and Euthyrox active ingredient) is a thyroid-hormone API used in endocrine formulation, analytical-development, and research programs where local regulations permit. Suzhou Pharmaceutical Technology Co., Ltd. supplies Levothyroxine Sodium API in controlled small-batch and bulk quantities from Suzhou, China, with export to South America, Australia, New Zealand, Mexico, Canada, and worldwide markets. Export documentation: COA and MSDS standard for all orders.
| Product Name | Levothyroxine Sodium |
| Structural Formula |  |
| Alias | L-thyroxine sodium; Thyroxine sodium; T4 sodium salt; Levotiroxina sódica; Synthroid active ingredient; Euthyrox active ingredient |
| CAS Number | 55-03-8 |
| Molecular Formula | C15H10I4NNaO4 |
| Molecular Weight | 798.85 g/mol |
| Purity | Available by agreed HPLC specification |
| Appearance | White to light yellow powder |
| Storage | Store sealed, protected from light and moisture |
> Applications
Levothyroxine Sodium is used by pharmaceutical and research organizations developing thyroid-hormone formulations, reference methods, and impurity-control strategies. API supply is intended for qualified buyers who will confirm dosage form, potency controls, impurity requirements, pharmacopoeial strategy, and finished-dose registration obligations in their own markets.
Thyroid-hormone formulation research
A 2017 NEJM journal article reported a randomized placebo-controlled trial of levothyroxine in older adults with subclinical hypothyroidism (NEJM, doi:10.1056/NEJMoa1603825, n=737). This supports the need for carefully controlled T4 API quality in endocrine formulation and analytical-development programs.
Analytical and impurity-control development
Buyers typically evaluate assay, related iodothyronine substances, residual solvents, water content, optical properties, particle properties, and stability behavior before moving from sample quantities to pilot or commercial batches. We supply API only, not finished tablets, injectable products, compounded preparations, or branded medicines.
> Sourcing & Supply
Suzhou Pharmaceutical Technology Co., Ltd. is an R&D-driven pharmaceutical company with in-house synthesis and analytical capability for Levothyroxine Sodium API. Small batches (up to 10 kg) are produced directly by our technical team in Suzhou. For larger commercial quantities, production is scaled up at qualified manufacturing facilities, with export documentation provided according to the order scope.
- Small-batch orders (≤10 kg): prepared by our technical team in Suzhou. Lead time 10–14 business days from order confirmation.
- Commercial bulk (>10 kg): scaled up at qualified manufacturing facilities. Lead time 14–21 business days depending on batch size and documentation.
We export Levothyroxine Sodium API to buyers across South America — including Brazil, Argentina, Colombia, Chile, Peru, Ecuador, Bolivia, Paraguay, and Uruguay — as well as to Australia, New Zealand, Mexico, and Canada. Inquiries from European, Middle Eastern, and Asian markets are also welcome.
> Quality & Export Documentation
All Levothyroxine Sodium shipments are accompanied by a Certificate of Analysis (COA) confirming identity, appearance, assay, and related substances against batch specification. Purity is tested by HPLC against an authenticated reference standard. MSDS is provided for all orders, and Certificate of Origin (COO) is available for commercial bulk shipments.
| Order size | Documentation included |
| ≤10 kg (small-batch / research) | COA + MSDS |
| >10 kg (commercial bulk) | COA + MSDS + COO |
> Packaging & Logistics
- 10 g, 25 g, 100 g: amber glass bottle or double-layered aluminium foil bag, light-protected
- 500 g, 1 kg: aluminium foil bag inside kraft paper box or fibre drum
- 5 kg, 10 kg: aluminium foil bag inside fibre drum
- >10 kg: packaging agreed according to commercial order requirements
Levothyroxine Sodium API is shipped with light- and moisture-protective packaging and batch labels matched to the COA. Shipping options include express courier for samples, air freight for kilogram orders, and sea freight for larger commercial shipments where timing allows.
> Pricing & Supply
Levothyroxine Sodium pricing is provided on request. We do not publish list prices because the final quote depends on order quantity, purity requirement, documentation needs, shipping destination, and current raw material costs.
- MOQ: 10 g for qualified buyers
- Sample policy: 1–5 g samples available for analytical confirmation
- Bulk discount tiers apply at 25 g, 100 g, 500 g, and 1 kg
- Payment: T/T (bank transfer). 100% in advance for standard orders. Terms for larger repeat orders by arrangement.
> Frequently Asked Questions
What is the minimum order quantity for Levothyroxine Sodium API?
The minimum order quantity for Levothyroxine Sodium API is 10 grams. Smaller analytical samples may be available for qualified buyers.
What documents are included with a Levothyroxine Sodium bulk order?
All Levothyroxine Sodium orders include a COA and MSDS in English. For commercial bulk orders above 10 kg, COO is available as standard export documentation.
Can I request a Levothyroxine Sodium sample before placing a bulk order?
Yes. Sample quantities of 1–5 g are available for qualified buyers before pilot or commercial orders.
Do you export Levothyroxine Sodium API to South America?
Yes. We support inquiries from Brazil, Argentina, Colombia, Chile, Peru, Ecuador, Bolivia, Paraguay, and Uruguay.
Can buyers in Australia, New Zealand, Mexico, or Canada order T4 sodium salt?
Yes. We supply Levothyroxine Sodium API to buyers in Australia, New Zealand, Mexico, and Canada. COA and MSDS are included with all orders.
What is Levothyroxine Sodium used for?
Levothyroxine Sodium is a thyroid-hormone API used in endocrine formulation, analytical-development, and research programs where local regulations allow.
Is T4 sodium salt the same as Levothyroxine Sodium?
Yes. T4 sodium salt is a common synonym for Levothyroxine Sodium, the sodium salt form of levothyroxine.
What specification is available for Levothyroxine Sodium CAS 55-03-8?
Levothyroxine Sodium is supplied by agreed HPLC specification, including assay, related iodothyronine substances, water content, and identity controls.
How is Levothyroxine Sodium packaged and shipped internationally?
Levothyroxine Sodium API is shipped in light-protective bottles, foil bags, or foil-lined fibre drums with protection from moisture during international transit.
Do you supply finished Levothyroxine Sodium tablets or injections?
No. We supply Levothyroxine Sodium API, not finished tablets, injectable products, compounded preparations, or branded medicines.
> Related Products
- Liothyronine Sodium | CAS 55-06-1 — sodium salt T3 API
- L-Liothyronine | CAS 6893-02-3 — triiodothyronine API
- Methylcobalamin | CAS 13422-55-4 — vitamin B12 API
- Gabapentin | CAS 60142-96-3 — neurological API
> Request a Quote or Sample
To request a quote or sample for Levothyroxine Sodium API (CAS 55-03-8), please contact us directly at Info@fmyykj.com.
Include in your inquiry: required quantity (grams or kg), destination country, documentation requirements (COA + MSDS standard; COO for bulk), and intended use (formulation / analytical development / research / other). We respond to all inquiries within 1 business day.
Last reviewed: June 2026