Levothyroxine, the most commonly prescribed thyroid medication in the world, has faced recurring supply disruptions. As of mid-2025, the injectable form of levothyroxine is listed on the American Society of Health-System Pharmacists shortage database, with multiple manufacturers affected. On the tablet side, EMD Serono announced in July 2025 that its branded product Euthyrox is being discontinued. While most oral levothyroxine tablets remain available through other manufacturers, spot shortages at individual pharmacies are possible, and the situation has been fluid across multiple countries for several years.
What’s Currently in Short Supply
The shortage picture depends on which form of levothyroxine you take. The injectable version, used primarily in hospitals for patients who can’t swallow pills, has been in shortage across all three major U.S. manufacturers: Fresenius Kabi, Par Pharmaceuticals, and Sagent. Multiple vial strengths (100, 200, and 500 mcg) are affected. This matters mostly for hospitalized patients and is less likely to affect people filling a monthly prescription at a retail pharmacy.
For oral tablets, the landscape is more stable but not without disruption. EMD Serono’s Euthyrox brand tablet (25 mcg) was listed by the FDA in July 2025 as “to be discontinued.” This follows a pattern: the brand-name product Levoxyl was recalled and pulled from the market for roughly a year back in 2013, forcing patients to switch to alternatives like Synthroid or generic versions. When any single manufacturer exits the market or pauses production, the remaining suppliers absorb that demand, which can create temporary gaps on pharmacy shelves.
This Is a Global Problem, Not Just a U.S. One
Supply shortages for thyroid hormones have hit numerous countries. A 2024 analysis of OECD nations found that multiple countries had experienced levothyroxine supply disruptions within the previous five years, with some facing ongoing shortages as of late 2024. The researchers noted that “no country operates in isolation,” meaning that raw material bottlenecks or manufacturing problems in one region ripple outward. Contributing factors include strict manufacturing standards that limit how quickly production can scale, raw material availability, and rising global demand driven partly by increasing diagnosis rates and, in some cases, overprescribing.
Why Switching Brands Isn’t Simple
Levothyroxine is what pharmacists call a narrow therapeutic index drug. Small differences in how much active ingredient your body absorbs can shift your thyroid levels enough to cause symptoms. A dose that’s slightly too high can cause anxiety, heart palpitations, and weight loss. A dose that’s slightly too low leaves you fatigued, cold, and mentally foggy. The margin between “right” and “wrong” is unusually thin compared to most medications.
This is why the American Thyroid Association has specifically recommended that patients avoid switching between levothyroxine products from different manufacturers. Even among generics that the FDA considers bioequivalent, the allowable range of variation means two different generic products could deliver meaningfully different amounts of the drug into your bloodstream. The ATA recommends that clinicians either prescribe a specific brand or specify the same generic manufacturer each time a prescription is filled.
If a shortage forces you to switch, your thyroid-stimulating hormone (TSH) level should be rechecked. The standard window for retesting is six to twelve weeks after the change, since it takes that long for your body to reach a new steady state on the different product. Until that recheck, you may notice subtle shifts in how you feel.
What to Do If Your Pharmacy Is Out
If your specific levothyroxine product isn’t available, you have several practical options. First, call other pharmacies in your area. Supply disruptions are often uneven, and a pharmacy across town may have your exact product in stock. Chain pharmacies can sometimes transfer stock between locations.
If your exact manufacturer isn’t available anywhere nearby, your doctor can write a new prescription for a different brand or generic. Synthroid (made by AbbVie) is the most widely distributed brand-name option and tends to have the most consistent availability. Tirosint, a soft-gel capsule, is another alternative. Generic tablets from manufacturers like Mylan, Lannett, or Sandoz may also be available.
A liquid formulation of levothyroxine exists as well. It absorbs faster than tablets and doesn’t need to be taken on an empty stomach, which some patients find more convenient. The liquid form has been commercially available in Europe for several years and is an option worth discussing with your prescriber, particularly if tablet shortages become a recurring problem. In studies, over 60% of patients who switched from tablets to liquid reported improved ease of treatment and better quality of life, largely because they no longer had to wait 30 to 60 minutes before eating breakfast. About 10% found the taste unpleasant and switched back.
How to Protect Yourself From Future Disruptions
Thyroid medication is taken daily for life by most people who need it, so even brief gaps in supply can be stressful. A few strategies can reduce your vulnerability. Ask your doctor to write your prescription specifying a manufacturer or brand rather than leaving it as “generic levothyroxine,” which allows the pharmacy to substitute freely based on whatever they have in stock. This gives you more consistency and makes it easier to track what you’re actually taking.
Keep a small buffer when possible. If your insurance allows 90-day fills through a mail-order pharmacy, that gives you a longer runway to find alternatives if supply tightens. Know the exact manufacturer, strength, and National Drug Code (NDC) of your current product so you can communicate precisely with pharmacists when checking availability.
If you do end up switching products, write down the date of the change and the new manufacturer. When you get your TSH rechecked six weeks later, this information helps your doctor interpret the results and adjust your dose if needed. Most people transition between products without major issues, but monitoring closes the loop and catches the cases where a dose adjustment is necessary.