Disclaimer
CompoundIQ publishes research summaries for informational and educational purposes only. Nothing on this site constitutes medical advice, diagnosis, or treatment recommendations. Always consult a licensed healthcare provider. Many compounds listed are research chemicals not approved for human use.
T3 (Liothyronine)
Also known as: Cytomel, Liothyronine, Triiodothyronine, T3
T3 (triiodothyronine) is the active thyroid hormone that regulates basal metabolic rate. Liothyronine (Cytomel) is the synthetic form used medically for hypothyroidism. In performance settings, it is used to elevate metabolic rate and accelerate fat loss, often during cutting phases.
Risk Level
High RiskDifficulty
Advanced| CAS Number | 6893-02-3 |
| Molecular Formula | C15H12I3NO4 |
| Class | Hormone |
| Category | Fat Loss Agents |
Mechanism of Action
T3 binds to nuclear thyroid hormone receptors, increasing transcription of genes involved in basal metabolic rate, thermogenesis, protein synthesis, and lipid metabolism. Exogenous T3 suppresses endogenous thyroid function via negative feedback on the HPT axis (TSH and TRH suppression). It increases oxygen consumption and caloric expenditure across virtually all tissues.
Dosing Research
Replacement dose: 25 mcg/day. Fat loss protocols typically use 25-75 mcg/day, starting at 25 mcg and titrating up by 12.5 mcg every few days. Taper down over 2 weeks when discontinuing to allow HPT axis recovery. Often combined with anabolic steroids to prevent muscle catabolism. Cycles of 6-8 weeks are common.
Side Effects & Risks
Muscle catabolism (especially without anabolic support), increased heart rate, palpitations, anxiety, tremors, heat intolerance, insomnia, bone loss with chronic use. Suppresses endogenous thyroid production; recovery can take weeks to months. Cardiac complications possible at high doses.
Research Studies
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Disclaimer
CompoundIQ publishes research summaries for informational and educational purposes only. Nothing on this site constitutes medical advice, diagnosis, or treatment recommendations. Always consult a licensed healthcare provider. Many compounds listed are research chemicals not approved for human use.