American Thyroid Association (ATA) Guideline
Pharmacokinetic Engine
Weight-Adjusted
Pharmacokinetic Engine
Weight-Adjusted
Levothyroxine Starting & Replacement Dosage Calculator
Accurately determine initial daily levothyroxine (T4) dose requirements based on clinical etiology (primary hypothyroidism, post-surgical thyroidectomy, or cancer suppression), adjusted for age and cardiovascular safety.
Thyroid replacement is calibrated precisely against body mass.
The degree of endogenous thyroid tissue destruction determines replacement intensity.
Elderly patients or those with coronary artery disease require lower initial dosing to prevent tachyarrhythmias.
Calculated Daily Replacement Dose
American Thyroid Association (ATA) & Endocrine Society Protocol
Standard Replacement
112 mcg
Closest Commercial Tablet: 112 mcg Tablet (Pink)
Titration & Monitoring Protocol
Take once daily in the morning with a full glass of water, at least 60 minutes before breakfast, espresso, or medications. Re-evaluate serum TSH and Free T4 in 6 to 8 weeks.
Clinical Pharmacokinetics:
- Exact Mathematical Dose: 108.8 mcg/day
- Available Commercial Tablet Strengths: 25, 50, 75, 88, 100, 112, 125, 137, 150, 175, 200 mcg
- Target TSH Window: 0.5 to 2.0 mIU/L (Primary Hypothyroidism)