LGD-4033 vs Liothyronine (T3)
Moderate Research vs FDA Approved
monitor Mechanism-based · 51% Both LGD-4033 and Liothyronine (T3) can raise blood pressure. Monitor BP regularly and consider adding cardiovascular support (cardarine, telmisartan, or similar).
Molecular Data
LGD-4033 Liothyronine (T3)
Weight 338.25 Da 650.97 Da
Half-life ~24-36 hours ~1 day
Type Nonsteroidal selective androgen receptor modulator (C14H12F6N2O) Thyroid hormone (C15H12I3NO4)
Key Benefits
LGD-4033
01 Strongest SARM for lean muscle mass accrual, with clinical trial data supporting dose-dependent increases in lean body mass
02 Tissue-selective action with minimal stimulation of the prostate and other androgen-sensitive tissues
03 Clinical evidence of improved physical function (leg press strength, stair-climbing speed) in hip fracture patients
04 No aromatization to estrogen (no estrogen-related water retention or gynecomastia at the receptor level)
05 No conversion to DHT (reduced risk of androgenic hair loss and prostate stimulation compared to testosterone)
06 Convenient once-daily oral dosing due to 24-36 hour half-life
07 Phase 2 clinical data available, providing a stronger evidence base than most other SARMs
Liothyronine (T3)
01 Direct and rapid increase in basal metabolic rate
02 Enhanced fat oxidation and lipolysis
03 Improved energy levels and reduction of hypothyroid fatigue
04 Faster-acting than T4 with effects noticeable within hours to days
05 Useful when peripheral T4-to-T3 conversion is impaired (illness, caloric deficit, stress)
06 Supports body temperature regulation and thermogenesis
07 Can improve cognitive clarity and reduce brain fog associated with low thyroid function
Side Effects
LGD-4033
Testosterone suppression (dose-dependent; more suppressive than Ostarine at equivalent doses, occurs in most users by week 4-6)
Water retention (non-estrogenic mechanism, typically mild to moderate, contributes to scale weight increase)
HDL cholesterol reduction (dose-dependent lipid impact observed in clinical trials)
Headaches (most common in the first 1-2 weeks, usually transient)
Fatigue or lethargy (related to testosterone suppression, typically becomes noticeable mid-cycle)
Reduced libido (related to HPG axis suppression, severity varies by dose and individual)
Liothyronine (T3)
Tachycardia and palpitations (increased heart rate, especially at higher doses)
Anxiety, nervousness, and irritability
Insomnia and disrupted sleep architecture
Increased sweating and heat intolerance
Tremor (fine hand tremor, similar to hyperthyroid presentation)
Increased appetite despite accelerated metabolism
Loose stools or increased bowel frequency
Contraindications
Pre-existing liver disease or elevated liver enzymes at baseline
Hormone-sensitive cancers (prostate cancer or other androgen-driven malignancies)
Pregnancy or potential pregnancy (teratogenic risk from androgen receptor agonism)
Breastfeeding
Age under 25 (incomplete endocrine system maturation and higher risk of HPG axis disruption)
Concurrent use of hepatotoxic medications without medical supervision
Known cardiovascular disease (insufficient long-term safety data for this population)
History of significant lipid abnormalities (LGD-4033 suppresses HDL)
Untreated adrenal insufficiency (must correct cortisol deficiency before starting T3)
Acute myocardial infarction or unstable angina
Thyrotoxicosis or untreated hyperthyroidism
Known hypersensitivity to liothyronine or any tablet excipients
Uncorrected adrenal cortical insufficiency (risk of adrenal crisis)
Research Evidence
LGD-4033 Liothyronine (T3)
Status Moderate Research FDA Approved
References 5 studies 5 studies
Latest 2018 September 2023
FDA Approved No Yes
This comparison is for educational and research purposes only. Consult a healthcare professional before use.