Cytomel (Liothyronine) is a synthetic T3 thyroid hormone used for hypothyroidism. Learn about its uses, dosage, cost, side effects, and what to know in 2026.
If you've been diagnosed with a thyroid condition — or your current thyroid medication isn't working well enough — your doctor may have mentioned Cytomel. Here's everything you need to know about this medication in 2026, from what it does to how much it costs.
Cytomel is the brand name for Liothyronine Sodium, a synthetic version of triiodothyronine (T3). T3 is one of two main thyroid hormones your body produces — the other being T4 (thyroxine). Cytomel provides your body with T3 directly, bypassing the need to convert T4 into T3.
Key facts about Cytomel:
To understand how Cytomel works in your body, check out our detailed mechanism of action guide.
Cytomel is FDA-approved for several uses:
The primary use of Cytomel is as replacement therapy for patients with hypothyroidism — an underactive thyroid that doesn't produce enough hormones. This includes:
Hypothyroidism can be present from birth (congenital) or develop later in life (acquired), often due to Hashimoto's disease, thyroid surgery, or radiation treatment.
Cytomel is used alongside surgery and radioactive iodine therapy in the management of well-differentiated thyroid cancer. It helps suppress TSH (thyroid-stimulating hormone) to reduce the risk of cancer recurrence.
Cytomel can be used in thyroid suppression tests to help diagnose mild hyperthyroidism or determine if the thyroid gland is functioning independently.
Some doctors prescribe Cytomel off-label for:
Cytomel comes in oral tablets in three strengths:
Typical dosing depends on your condition, age, and other health factors:
Cytomel is not safe for everyone. You should not take it if you have:
People with heart disease, elderly patients, and those with adrenal problems need to start at very low doses under close medical supervision.
Cost depends on whether you're getting the brand name or generic:
Generic Liothyronine is generally covered by most insurance plans and Medicare Part D. Brand-name Cytomel may require prior authorization or may not be on your plan's preferred formulary. Some insurers require you to try Levothyroxine first (step therapy) before they'll cover Cytomel.
There are several ways to reduce your costs:
For a complete breakdown, see our guide on how to save money on Cytomel.
The most common side effects of Cytomel include headache, nervousness, sweating, tremor, diarrhea, and heat intolerance. These usually mean the dose is slightly too high and often improve with adjustment. For a detailed list of side effects and when to seek help, read our Cytomel side effects guide.
Cytomel and generic Liothyronine have experienced intermittent supply disruptions. If your pharmacy is out of stock, use Medfinder to check availability at pharmacies near you.
Cytomel is an effective thyroid medication that plays an important role for patients who need direct T3 supplementation. Whether you're newly prescribed or considering switching from another thyroid medication, understanding how it works, what it costs, and how to take it properly will help you get the most from your treatment.
If you need help finding Cytomel in stock, Medfinder can show you which pharmacies near you have it available right now.
You focus on staying healthy. We'll handle the rest.
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