Comprehensive medication guide to Liothyronine including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
$0–$30 copay for generic liothyronine; typically Tier 1–2 on most insurance and Medicare Part D formularies. Prior authorization is generally not required for hypothyroidism.
Estimated Cash Pricing
$25–$85 retail for generic liothyronine; as low as $21–$25 with a GoodRx or SingleCare coupon for a 30-day supply. Brand-name Cytomel costs significantly more.
Medfinder Findability Score
65/100
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Liothyronine is a synthetic form of triiodothyronine (T3), one of the two main hormones produced by the thyroid gland. It is sold under the brand name Cytomel (oral tablets) and Triostat (IV injection for hospital use). Liothyronine has been FDA-approved since 1956 and is available as a generic medication.
Unlike levothyroxine (T4), which must be converted to active T3 in the body, liothyronine is already in the biologically active form. It acts faster than levothyroxine — with onset within hours — but has a shorter half-life of approximately 2.5 days. It is used to treat hypothyroidism, support thyroid cancer management, and in some cases augment treatment-resistant depression.
Liothyronine oral tablets come in three strengths: 5 mcg, 25 mcg, and 50 mcg. The usual adult maintenance dose for hypothyroidism is 25–75 mcg once daily, individualized based on TSH and free T3 levels.
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Liothyronine works by entering cells and binding to thyroid hormone receptor proteins in the cell nucleus. This hormone-receptor complex activates gene transcription — switching on the genes that direct cells to produce proteins responsible for metabolism, heart function, body temperature regulation, neurological activity, and dozens of other biological processes.
T3 (liothyronine) has much higher affinity for thyroid hormone receptors than T4 (levothyroxine). This is why T3 is considered the "active" form — it doesn't need to be converted before it can affect cellular function. The drug is approximately 95% absorbed from the GI tract within 4 hours, reaches peak plasma levels in 2–3 hours, and has a biological half-life of about 2.5 days.
The physiological actions of liothyronine include: increasing basal metabolic rate, enhancing mobilization of glycogen stores, promoting gluconeogenesis, supporting protein synthesis, and regulating cardiovascular function. These effects collectively restore normal bodily function in patients with insufficient thyroid hormone production.
5 mcg — tablet
Starting dose for elderly patients and those with cardiovascular disease; increase by 5 mcg every 2 weeks
25 mcg — tablet
Most common starting dose for adults with mild hypothyroidism; usual maintenance 25–75 mcg/day
50 mcg — tablet
Higher-dose maintenance therapy; used in thyroid cancer TSH suppression and higher-dose requirements
10 mcg/mL — IV injection (Triostat)
Hospital use only for myxedema coma; not dispensed at retail pharmacies
As of 2026, liothyronine oral tablets are not on the FDA's official national drug shortage list — meaning there is no manufacturer-reported, nationwide supply disruption. However, localized availability gaps exist at some pharmacies, particularly for brand-name Cytomel and the 5 mcg tablet strength.
Chain pharmacies stock liothyronine in smaller quantities than high-volume medications like levothyroxine. Growing demand — partly driven by patients transitioning off desiccated thyroid medications following FDA enforcement actions in August 2025 — has the potential to create temporary regional shortfalls. Independent pharmacies and mail-order options tend to have more reliable access.
If you're having trouble finding liothyronine at your pharmacy, medfinder can call pharmacies near you to find which ones have your specific strength in stock — so you don't have to spend time on hold with pharmacy phone systems.
Liothyronine is not a controlled substance, so any licensed prescriber with authority to prescribe medications can write a prescription for it — no special DEA scheduling requirements apply. The drug is most commonly prescribed by specialists and primary care clinicians who manage thyroid disorders.
Endocrinologists: Most experienced with thyroid hormone management; most likely to prescribe T3 or combination T4/T3 therapy
Primary care physicians (PCPs) and internists: Frequently prescribe liothyronine for hypothyroidism management
Nurse practitioners (NPs) and physician assistants (PAs): Can prescribe liothyronine in most states with prescriptive authority
Integrative and functional medicine physicians: Often familiar with T3 and combination T4/T3 prescribing; may be more open to this approach
Oncologists and surgeons: May prescribe for TSH suppression in well-differentiated thyroid cancer patients
Psychiatrists: May prescribe off-label as an augmentation strategy for treatment-resistant depression
Telehealth is available for liothyronine prescriptions through platforms offering thyroid-focused or endocrinology care. Patients typically need recent lab work (TSH, free T4, free T3) for an initial telehealth visit. This is especially useful in areas with limited endocrinology access.
No. Liothyronine is not a controlled substance and is not scheduled by the DEA. Any licensed prescriber — including primary care physicians, nurse practitioners, physician assistants, and specialists — can write a prescription for it without special DEA registration requirements.
Because liothyronine is not a controlled substance, prescriptions can be filled and refilled without special documentation. However, it does carry an FDA boxed warning: it should NOT be used for weight loss or obesity treatment. Doses above the therapeutic range can cause serious or life-threatening side effects, particularly when combined with sympathomimetic weight-loss medications.
Most side effects of liothyronine reflect too much thyroid hormone (overtreatment). Common side effects include:
Palpitations or increased heart rate
Nervousness, anxiety, or irritability
Insomnia
Headache
Sweating and heat intolerance
Weight loss or increased appetite
Tremor and diarrhea
Arrhythmias, including atrial fibrillation (most common serious cardiac effect)
Chest pain or angina (especially in patients with coronary artery disease)
Decreased bone mineral density with long-term overtreatment (especially post-menopausal women)
Thyroid storm/thyrotoxicosis from severe overdose
Serious cardiovascular toxicity when combined with weight-loss sympathomimetic drugs (boxed warning)
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Levothyroxine (Synthroid, Tirosint)
Synthetic T4 hormone; first-line standard of care for hypothyroidism; more stable levels than liothyronine; widely available at all pharmacies
Armour Thyroid (desiccated porcine thyroid)
Contains both T4 and T3 in a fixed ratio; currently facing FDA regulatory challenges in 2025-2026; harder to find than liothyronine
Tirosint (levothyroxine gel capsule)
Gel-cap formulation of levothyroxine with fewer inactive ingredients; superior absorption for patients with GI conditions
Compounded T3/T4 preparations
Custom-compounded thyroid hormone preparations; available from compounding pharmacies; not FDA-approved; require a specific prescription
Prefer Liothyronine? We can find it.
Warfarin (and other anticoagulants)
majorLiothyronine significantly increases the anticoagulant effect of warfarin. INR must be monitored closely when initiating, changing, or stopping liothyronine. Warfarin dose reduction is often needed.
Insulin and antidiabetic medications
moderateLiothyronine may worsen glycemic control, potentially requiring higher doses of insulin or oral antidiabetics. Monitor blood glucose carefully after initiating or adjusting T3 therapy.
Tricyclic antidepressants (amitriptyline, imipramine)
majorCombination increases toxic effects of both drugs via increased catecholamine receptor sensitivity. Risk of cardiovascular and CNS side effects including arrhythmias.
Sympathomimetic amines (weight-loss medications)
majorFDA boxed warning: combining liothyronine with sympathomimetic weight-loss drugs can cause life-threatening cardiovascular toxicity. Avoid this combination.
Bile acid sequestrants (cholestyramine, colesevelam)
moderateBind to liothyronine in the GI tract, reducing absorption by up to 50%. Take liothyronine at least 4 hours before or after these medications.
Digoxin
moderateLiothyronine reduces the therapeutic effect of digoxin. Monitor digoxin levels when initiating or adjusting T3 therapy.
Beta-blockers (metoprolol, propranolol)
minorLiothyronine may reduce the effectiveness of beta-blockers. Conversely, beta-blockers help manage some T3 side effects like palpitations.
Rifampin
moderateIncreases metabolism of liothyronine, potentially reducing T3 levels. Dose adjustment of liothyronine may be needed.
Amiodarone
majorComplex interaction affecting thyroid hormone metabolism and function in multiple ways. Close monitoring of thyroid function tests required.
Estrogen and oral contraceptives
moderateEstrogen increases T4-binding globulin, potentially reducing free T3 levels. Women starting or stopping hormonal contraceptives may need thyroid dose adjustments.
Liothyronine is a well-established synthetic thyroid hormone that plays a critical role for many patients who need T3 supplementation — whether because of poor T4-to-T3 conversion, thyroid removal, thyroid cancer management, or persistent symptoms despite levothyroxine therapy. It is affordable as a generic, available at most pharmacies, and not in a formal national shortage in 2026.
That said, localized availability gaps can occur — particularly for the 5 mcg strength and brand-name Cytomel. The best strategy is to refill early, use the generic formulation when possible, and maintain a 90-day supply prescription to reduce refill frequency. If cost is a concern, free discount cards like GoodRx and SingleCare can reduce the price to $21–$25 per month.
If you're struggling to find liothyronine in stock at your pharmacy, medfinder is here to help. Enter your medication, dosage, and location and we'll find pharmacies near you with it in stock — so you can focus on your health, not your pharmacy search.
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