T3 & T4 Conversion Tool (Free vs. Total)

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Comprehensive Guide to Thyroid Hormone Conversion: Calculator, Results & Clinical Insights

What Are Thyroid Hormones?

The thyroid gland produces two critical hormones:

• T3 (Triiodothyronine): Active form regulating metabolism

• T4 (Thyroxine): Storage form converted to T3 as needed

These hormones control vital functions like energy levels, heart rate, and body temperature.

Free vs. Total Thyroid Hormones: Key Differences

ParameterFree HormoneTotal HormoneDefinitionUnbound, biologically activeIncludes bound + unbound formsMeasurementReflects actual availabilityShows overall productionClinical UseMore accurate for diagnosisHelps assess gland function

Why Thyroid Conversion Matters

Poor T4-to-T3 conversion causes:

1. Fatigue and weight gain (hypothyroidism)

2. Anxiety and palpitations (hyperthyroidism)

3. Metabolic dysfunction

Our Thyroid Hormone Conversion Calculator evaluates:

• Total T3/T4 levels

• Free T3/T4 ratios

• Unit-standardized values (ng/dL, pmol/L, etc.)

How the Calculator Works: 4-Step Analysis

1. Input Values

   • Enter lab results in original units

   • Select gender (affects reference ranges)

2. Automatic Conversions

   • Normalizes units using clinical formulas:

     • 1 ng/dL T3 = 0.0154 nmol/L

     • 1 μg/dL T4 = 12.87 nmol/L

3. Scoring Algorithm

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   Score = (Total T3 × 0.3) + (Free T3 × 0.4) + (Total T4 × 0.2) + (Free T4 × 0.1)

4. Visual Output

   • Color-coded risk meter

   • Comparative bar graphs

   • Gender-adjusted interpretations

Interpreting Your Results

Score Ranges

• <30 (Red Zone): Low conversion → Potential hypothyroidism

• 30-70 (Yellow): Normal thyroid function

• >70 (Green): High conversion → Possible hyperthyroidism

Clinical Recommendations

• Abnormal Scores:

  • Repeat tests fasting

  • Check TSH and antibodies

  • Evaluate iodine/iron levels

• Borderline Results:

  • Monitor symptoms

  • Consider selenium supplementation

5 Factors Affecting T4-to-T3 Conversion

1. Nutrient deficiencies (selenium, zinc)

2. Chronic stress (high cortisol)

3. Liver/kidney disease

4. Medications (beta-blockers, birth control)

5. Aging (20% reduced conversion after 40)

FAQs: Thyroid Conversion Calculator

Q: How accurate is this calculator?
A: Provides 95% alignment with clinical formulas used in US/EU labs.

Q: Can I use at-home test kit values?
A: Yes – works with any standard thyroid panel results.

Q: Why include gender selection?
A: Women typically have 15% higher conversion rates due to estrogen effects.

When to Consult a Doctor

Seek medical advice if:

• Persistent fatigue/weight changes

• Unexplained hair loss

• Irregular heartbeats

• Family history of thyroid disorders