Liothyronine
Cytomel (liothyronine) is a synthetic form of the thyroid hormone triiodothyronine (T3), used primarily to treat hypothyroidism when patients need direct T3 hormone replacement. It is typically prescribed when other thyroid medications are insufficient or when a patient cannot adequately convert T4 to T3.
Cytomel is a prescription thyroid hormone medication used to treat underactive thyroid conditions by providing synthetic T3 hormone replacement.
Key facts at a glance
- RxNorm
- 3081
- Generic
- Cytomel
- Class
- brand-name
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Cytomel is used to treat hypothyroidism (underactive thyroid), including myxedema coma, and may be used in combination with other thyroid medications. It may also be prescribed for thyroid cancer and goiters when thyroid hormone replacement is needed.
Cytomel contains synthetic liothyronine sodium, which is chemically identical to the naturally occurring T3 hormone produced by the thyroid gland. It binds to thyroid hormone receptors in cells throughout the body to regulate metabolism, energy production, and growth and development.
Cytomel should not be used for weight loss or obesity treatment. It may interact with blood thinners, diabetes medications, and certain antidepressants. Patients with heart disease, adrenal insufficiency, or untreated thyrotoxicosis should use caution. Dosage must be individualized and monitored through thyroid function tests. Do not discontinue without consulting your healthcare provider.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy