This page describes pharmacological agents that may have legal restrictions, side effects, and drug interactions in your jurisdiction. Information is for educational research only — consult a clinician before considering any compound.

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T3 / Liothyronine

Emerging

Active thyroid hormone.

Aliases (4)

Cytomel · Tertroxin · Liothyronine sodium · T3

TYPICAL DOSE

25 mcg/day

Daily

ROUTE

Oral (tablet)

Oral

CYCLE

4-8 weeks on

As prescribed

STORAGE

Room temp; original container

Room temp

Overview

What is T3 / Liothyronine?

Liothyronine is the pharmaceutical name for synthetic triiodothyronine (T3) — the active thyroid hormone. It is FDA-approved for hypothyroidism, myxedema, and some cases of T4-resistant or treatment-resistant depression as adjunctive therapy.

Key Benefits

Provides immediate thyroid hormone activity (vs T4 which requires conversion), useful in T4-monotherapy non-responders, can augment SSRI response in depression, and supports metabolic rate, thermogenesis, and energy.

Mechanism of Action

T3 binds nuclear thyroid hormone receptors (TRα and TRβ), forming a transcription factor that regulates genes governing basal metabolic rate, mitochondrial biogenesis, lipolysis, and protein synthesis. It also has non-genomic effects on Na+/K+-ATPase and mitochondrial function.

▸Brand options4 known

CytomelTertroxinLiothyronine sodiumT3

StatusRx (US, EU, AU); OTC in India and several other markets; gray-market via bodybuilding sources

Peptide Interactions

SSRI / SNRI / TCA (in TRD):

Synergistic

T3 augmentation has clinical precedent — but only with depression diagnosis and psychiatrist oversight.

Levothyroxine (T4):

Synergistic

Some hypothyroid patients respond better to T4+T3 combination than T4 alone — controversial, mixed evidence.

Stimulants (caffeine high-dose, modafinil at supraphysiologic T3 doses, amphetamines):

Avoid

Additive cardiovascular load — tachycardia, BP elevation, arrhythmia risk

Sympathomimetics (decongestants, clenbuterol, ephedrine):

Avoid

Same — additive CV strain. Bodybuilding "T3 + clenbuterol" stacks are a known cause of cardiac events.

Anticoagulants (warfarin):

Avoid

T3 increases warfarin sensitivity → ↑ INR → bleeding risk; requires INR monitoring

Insulin / oral hypoglycemics:

Avoid

T3 alters glucose metabolism; insulin requirement may change

β-blockers:

Avoid

Not a "don't combine" — actually used clinically to manage hyperthyroid symptoms (propranolol blocks peripheral T4→T3 conversion at high doses). But this is …

Quality Indicators

✓

Pharmacy-dispensed, intact packaging

Prescription tablets in original sealed packaging from a licensed pharmacy.

Generic vs branded

Generics are usually fine but bioavailability can vary slightly; track if you switch.

✗

Unbranded blister or counterfeit risk

Counterfeit pharmaceuticals are a known issue; verify pharmacy and lot if buying internationally.

What to Expect

Day 1
PK-driven acute peak per administration. Verify dose tolerated.
Week 1
Steady-state reached for most daily-dosed pharma.
Week 2-4
Therapeutic effect established; titration window if needed.
Long-term
Periodic monitoring per drug class (labs, BP, ECG as applicable).

Side Effects & Safety

Common (>10% in supraphysiologic use): Tachycardia, palpitations, tremor, heat intolerance, sweating, weight loss, anxiety, insomnia, increased appetite, diarrhea, headache.
Less common (1-10%): Hair loss (usually transient at start), menstrual irregularities, muscle weakness/cramping.
Rare-serious (<1% but worth knowing):
- Atrial fibrillation — particularly with supraphysiologic dosing or in subjects with subclinical CV disease. Older subjects at higher risk but reported in young bodybuilders abusing T3.
- Supraventricular tachyarrhythmia — including SVT, atrial flutter
- Heart failure / high-output failure with chronic excess
- Osteoporosis — accelerated bone loss with chronic supraphysiologic exposure (especially concerning in young athletes — peak bone mass accrual continues to ~age 25-30)
- Thyroid storm — life-threatening, usually from massive overdose or in subjects with underlying thyroid pathology
- Adrenal crisis — if started in subject with concurrent untreated adrenal insufficiency
Watch periods: First 2-4 weeks for CV symptoms (HR >100, palpitations, chest discomfort → stop). Bone density concerns are chronic (>6 months supraphysiologic).