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TSH Dose Adjustment Calculator

Work out tsh dose adjustment instantly with clear inputs, formula shown and shareable results.

About TSH Dose Adjustment Calculator

Applies the conventional 12.5 to 25 microgram levothyroxine adjustment steps based on TSH, and shows the weight-based full replacement dose of 1.6 mcg/kg/day.

Formula

Levothyroxine adjustment

Full replacement = 1.6 mcg/kg/day; adjust by 12.5-25 mcg when TSH is outside target and retest after 6-8 weeks

Worked example

With the default values below, TSH Dose Adjustment Calculator returns Suggested dose of 112.5. Change any input above and every figure here is recalculated in your browser.

Inputs used

Body weightaccepts 20–200 kg
70 kg
Current levothyroxine doseaccepts 12.5–400 mcg/day
100 mcg/day
Current TSHaccepts 0.01–100 mIU/L
6.5 mIU/L

Results

Suggested dose
112.5 mcg/day
Change applied
12.5 mcg/day
Full weight-based replacement dose
112 mcg/day
Retesting interval
Retest TSH 6 to 8 weeks after the change

Step by step

  1. 1Values used
  2. 2Levothyroxine adjustment
  3. 3Suggested dose= 112.5 mcg/day
  4. 4Change applied= 12.5 mcg/day
  5. 5Full weight-based replacement dose= 112 mcg/day
  6. 6Retesting interval= Retest TSH 6 to 8 weeks after the change

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
  • This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

Frequently Asked Questions

Why wait six weeks?

Levothyroxine has a one-week half-life, so TSH takes about six weeks to reach a new steady state.

Are smaller steps used in older people?

Yes. 12.5 mcg steps and higher TSH targets are usual in older adults and cardiac disease.

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