Where Is Synthroid Made? Understanding Levothyroxine’s Manufacturing Origin and How to Save
This article was updated on 5/6/2025 to expand on the manufacturing origin of generic levothyroxine sold in the United States. A previous version included Lannett Company as a current manufacturer and distributor of levothyroxine sodium in the United States. According to the NDC database, the company is a labeler for the product. However, other FDA databases did not list Lannett’s levothyroxine under an approved marketed status.
Transparency should be a given when it comes to the products we put into our bodies. Yet, something as seemingly straightforward as where a medication is made or why its price can swing so dramatically from one pharmacy to the next often turns into a confusing maze of incomplete information. Synthroid (levothyroxine), a daily essential for millions managing thyroid conditions, is no exception. In this post, PharmacyChecker untangles the latest data on Synthroid’s origins and pricing so you can make informed choices about your care.
What is levothyroxine?
Levothyroxine sodium, often referred to simply as “levothyroxine” or the brand name, is a prescription generic medication used to treat hypothyroidism. It’s also prescribed to treat an enlarged thyroid gland and thyroid cancer.
Hypothyroidism affects about five out of every 100 people in the U.S., yet it’s estimated that around 60% of people with a thyroid disorder don’t know they have it. Common symptoms of hypothyroidism include fatigue, cold intolerance, constipation, dry skin, hair loss, muscle weakness, weight gain, and fertility issues. When left untreated, it can seriously impact a person’s quality of life.
Where Is Synthroid (levothyroxine) Made?
Synthroid is a brand-name levothyroxine marketed by AbbVie Inc. in the United States. As reported in PharmacyChecker’s “Not Made in the USA” study, 71% of brand-name medications sold in U.S. pharmacies are manufactured abroad. Even when the product is made in the U.S., many of its active pharmaceutical ingredients (APIs) and excipients may be imported.
AbbVie likely manufactures Synthroid for the U.S. market in Ireland, Italy, Germany, or the United States (including Puerto Rico). Below, we break down why we’ve drawn that conclusion.
On April 16, 2025, PharmacyChecker submitted an inquiry to Abbvie’s Medical Information Site requesting the following information:
- where Synthroid for the US market is manufactured
- where the active ingredient is sourced from
- where the final drug product is formulated
They responded with the following PRODUCT ORIGIN sheet:
As you can see, the information is notably vague:
“This product [SYNTHROID] is manufactured in North America and/or Europe.”
The information provided by AbbVie about Synthroid’s origin appears to have only grown more and more vague since our research in 2019, during which the company wrote to PharmacyChecker the following:
"Synthroid marketed in the United States is manufactured in the United States, Puerto Rico, and Ireland (Data on file, AbbVie). AbbVie sources ingredients for Synthroid marketed in the United States from the United States, Puerto Rico, France, Italy, Japan, Mexico, and Germany.
This information is subject to change. If this information is needed in the future, please contact AbbVie Global Medical Information for updated information.”
On April 22nd, 2025, PharmacyChecker called AbbVie’s Medical Information line to again inquire about Synthroid’s origins. When pressed for more details via phone in April 2025, an AbbVie representative reiterated:
ABBVIE: "Per the data we have on file, the product is manufactured in North America and/or Europe."
PHARMACYCHECKER: “You don't know the facility location or even country-specific information?”
ABBVIE: “No, that's the data we have on file.”
Below, a U.S. label from 2023 only shows an AbbVie Inc. address in North Chicago, Illinois, USA. As of April 2025, AbbVie's facility at 1401 Sheridan Road, North Chicago, IL 60064, is a manufacturing site registered for analysis, API manufacture, and manufacture, per FDA Drug Establishments data. Abbvie also has another establishment at 1 N Waukegan Rd, North Chicago, IL 60064 that is registered for analysis, label, manufacture, and pack. It is likely that this particular packaged product is made in Illinois. If the active pharmaceutical ingredient was sourced from elsewhere, labeling laws would dictate that information be displayed on the label.
As of April 2025, AbbVie has manufacturing establishments in Massachusetts (USA), Puerto Rico (USA), Germany, Illinois (USA), Michigan (USA), Ireland, Singapore, and Italy registered with the FDA. If that’s the case, based on our vague correspondence with AbbVie, AbbVie likely only manufactures Synthroid in Ireland, Italy, Germany, or the United States (including Puerto Rico). An Irish regulatory filing confirms that levothyroxine (the API in Synthroid) is processed at Sligo, although that does not guarantee the product is then distributed to the U.S. market.
Generic Levothyroxine Manufacturing Origins
Generic versions of Synthroid (levothyroxine sodium) tablets are widely available in the United States and are associated with several different pharmaceutical companies. PharmacyChecker found packaging indicating that Intas Pharmaceuticals manufactures the tablets in India for packager Accord Healthcare.
Lloyd Inc. manufactures levothyroxine tablets in Iowa (USA) for the distributor, Alvogen.
Ascent Pharmaceuticals manufactures levothyroxine tablets in New York (USA).
Mylan’s, Macleods, and Lupin levothyroxine are made in India.
Here’s an interesting one. According to the FDA database of national drug codes (NDCs), Lannett Company is a labeler for levothyroxine sodium tablets marketed in the United States certified up until the end of 2025. According to the packaging (below), Lannett’s active ingredient is produced in Austria, and its finished drug product is formulated by Neolpharma Inc. in Caguas, Puerto Rico (USA). Lannett’s website is still quite explicit in that its Levothyroxine Sodium tablets are manufactured in Caguas, Puerto Rico, USA, although this information may be out-of-date. The Caguas facility, operated by Neolpharma, does appear to handle the production or packaging for Lannett’s levothyroxine supply. (Notably, this same Puerto Rico site was impacted by Hurricane Maria in 2017, contributing to temporary drug shortages.) Upon reviewing the FDA's other databases, however, there is no current evidence indicating that Lannett Company, Inc. holds an approved FDA-marketed status for levothyroxine sodium tablets.
Origins of Other Levothyroxine Formulations
Additionally, PharmacyChecker found packaging of generic levothyroxine capsules sold in the United States that indicates the capsules are it is made in Switzerland by IBSA Institut Biochimique for packager Lannett. The NDC database also indicates that Lannett is a labeler of this product, but this product is not included as an approved marketed product in the FDA Orange Book.
The Swiss company, IBSA, is responsible for manufacturing and distributing a unique levothyroxine formulation called Tirosint (a liquid-filled softgel capsule) and Tirosint-SOL (oral solution) for the U.S. market. They make both products in Switzerland.
Packaging of levothyroxine powder for intravenous (IV) injection, below, indicates it’s manufactured and packaged by Zydus Lifesciences Limited, a company with several registered manufacturing drug establishments in India.
Is ‘Canadian’ Synthroid the same as ‘American’ Synthroid?
In 2019, readers of PharmacyChecker Blog began to speculate that Canadian sold Synthroid “works better” than Synthroid sold in the United States and India. At the time, we conducted an investigation and concluded that Synthroid sold in the United States and Synthroid sold in Canada were likely the same medication. See: Is Synthroid in Canada the same as in the U.S.?
Today, that’s likely no longer the case: Synthroid sold in the United States is marketed by AbbVie (which, again, likely only manufactures its Synthroid in Ireland, Italy, Germany, or the United States (including Puerto Rico)). According to a product monograph available on Health Canada’s registry, Synthroid sold in Canada is a registered trademark of Mylan Healthcare GmbH with licensed use by BGP Pharma ULC, a Mylan company. BGP Pharma ULC’s company address is listed as 85 Advance Road, Etobicoke, Ontario, M8Z 2S6, Canada.
What about Synthroid Prices?
Whether you take brand-name Synthroid or generic levothyroxine, comparing prices on PharmacyChecker.com can make a big difference. The Synthroid price comparison is a typical case of the generic being cheapest in the United States and the brand product most affordable if ordered from an international online pharmacy.
| Medication | Strength (Quantity) | U.S. Discount Coupon Price | International Online Pharmacy Price |
| Levothyroxine (Generic) | 25 mcg (90 tablets) | $9.06 | $24.30 |
| Synthroid | 25 mcg (90 tablets) | $146.70 | $32.40 |
In summary, generic levothyroxine is the most cost-effective option for most U.S. patients, often available for only a few dollars per month. If you have concerns that switching between different generics may affect your thyroid levels, levothyroxine tablets from the following manufacturers should be equivalent to each other and other manufacturers per the FDA Orange Book:
- Accord Healthcare Inc
- Macleods Pharmaceuticals LTD
- Mylan Pharmaceuticals Inc
- Watson Laboratories Inc, an indirect wholly owned subsidiary of Teva Pharmaceuticals USA Inc
But for those patients outside the U.S. or those who require or prefer the brand Synthroid, obtaining the brand from an international online pharmacy can yield substantial savings. Also, if you’re eligible, AbbVie’s own “Synthroid Delivers” program can cap costs at $25/month for a 90-day prescription.
Other popular brand drugs price comparisons on PharmacyChecker.com that include levothyroxine as an active ingredient: Eltroxin, Euthyrox, Levoxyl, Tirosint
Although these medications contain the same active ingredient, they are not considered interchangeable. It’s always important for patients to consult their healthcare provider before switching products or sourcing medications internationally, especially with a narrow therapeutic index drug like levothyroxine, where consistent dosing is critical.
PharmacyChecker verifies international online pharmacies for consumer safety, to help patients around the world avoid rogue online pharmacies and counterfeit drugs. The National Bureau of Economic Research (NBER) had a working paper based on an audit of test samples of brand-name prescription medications from U.S. and international websites, the results of which strongly demonstrate the safety of ordering medications from an international online pharmacy approved in the PharmacyChecker International Pharmacy Verification Program.
We have been recognized in the Journal of the American Medical Association (JAMA) as a trusted resource for identifying reputable online pharmacies that provide high-quality prescription drugs at lower prices. According to JAMA, international online pharmacies stand out as a vital option for patients requiring expensive brand-name drugs, particularly when domestic options remain unaffordable. Utilizing an international online pharmacy has been proven to save patients a great deal of money, thereby increasing access and adherence to prescribed medicines.
Our Takeaway
Synthroid’s global manufacturing footprint and price variability highlight the importance of transparency and affordability in prescription drug access. At PharmacyChecker, we advocate for patients to compare prices at U.S. pharmacies and accredited international online pharmacies to find the best value.
Whether you're managing hypothyroidism or comparing brand vs. generic, consult your doctor and pharmacist about the best treatment for you – and let PharmacyChecker.com help you save on it.
