Jeffrey Panko NP Psychiatry · Patient education
Triiodothyronine (T3)
Liothyronine / Cytomel / Thyroid hormone
A guide for adults taking triiodothyronine (t3).
Follow the directions on your prescription and your provider's recommendations.
Formulations: Oral tablets are measured in micrograms, not milligrams. Liothyronine and levothyroxine (T4) are different hormones and are not interchangeable dose for dose.
What it is used for
Liothyronine replaces thyroid hormone in selected thyroid conditions. In psychiatry, it is sometimes added off-label to antidepressant treatment. It is not approved for weight loss and should never be used for that purpose.
How it works
T3 is an active thyroid hormone that affects metabolism and many organ systems. Depression augmentation can be considered in selected cases, but excess thyroid hormone can harm the heart and bones.
What to expect over time
Review mood and daily function over the agreed trial period, alongside thyroid tests. Feeling overstimulated is not evidence that the antidepressant effect is better.
Taking your medication
- Take consistently according to your prescription and food instructions.
- Follow the clinic’s timing instructions for blood tests; report the time of your last dose.
- Do not double a missed dose without instructions.
- Do not increase the dose for energy or weight loss. Consult with your provider before changing treatment.
When to get help
Emergency symptoms. Get emergency care for chest pain, collapse, a severe irregular heartbeat, or severe confusion with fever.
Prompt medical advice. Report persistent palpitations, tremor, sweating, insomnia, or unexplained weight loss promptly.
If you feel unsafe or have thoughts of self-harm, call 911 or go to an emergency department.
Possible side effects
- Palpitations or faster pulse
- Tremor, sweating, or heat intolerance
- Anxiety, irritability, or insomnia
- Diarrhea or unintended weight loss when exposure is excessive
Keeping track of treatment
Some side effects resolve with time; others may require a change of medication. Discuss persistent or bothersome side effects with your provider.
Thyroid tests, pulse, blood pressure, and clinical symptoms guide treatment. Heart-risk assessment and bone-health monitoring may be appropriate during longer use.
If you take too much
For a suspected overdose, call Poison Control at 1-800-222-1222 immediately, even if you feel well. Call 911 for a seizure, collapse, trouble breathing, or inability to wake.
Before you start
Uncorrected adrenal insufficiency is a contraindication. Discuss heart disease, arrhythmias, osteoporosis, diabetes, and all thyroid treatment.
Discuss pregnancy, pregnancy plans, and breastfeeding with your provider. Treatment decisions should consider both the medication and the condition being treated.
Medicines and interactions
Review all your medications with your provider, including over-the-counter medicines and supplements. Have new medications checked before taking them.
Calcium, iron, antacids, and certain binding medicines can affect absorption; obtain a spacing plan for your exact regimen.
Anticoagulants, diabetes medicines, stimulants, and some antidepressants may require monitoring or adjustment. Biotin supplements can interfere with thyroid laboratory results.
Everyday tips
Keep one coordinated list of thyroid medicines and supplements.
Report pregnancy promptly so thyroid and psychiatric care can be coordinated.
Your questions answered
Does adding T3 mean I have hypothyroidism?
Not necessarily. Psychiatric augmentation is a separate off-label use. Confirm the goal and monitoring plan.
Can I use it to lose weight?
No. Excess thyroid hormone can cause serious or fatal toxicity, especially with stimulants.
Storage and safety
Keep medication in its labeled container, away from excess heat and moisture and out of reach of children and pets. Do not share it. Ask a pharmacy about disposal of unused medication.
Sources
About this information
Educational handout; does not replace your prescription or provider's recommendations.
Educational inclusion does not mean this medication or its indications are treated at this practice. Review the guide for your exact product with your prescriber or pharmacist.