ATA Guidelines for Hypothyroidism
Thyroid (2014)
Levothyroxine remains recommended first-line treatment with goal TSH in lower half of reference range for most patients.
Levothyroxine (T4)
Oral tablet (25 to 150mcg)Available in all 50 statesMarketing purposes only. Actual medications, if prescribed, are dispensed by a licensed pharmacy.
thyroid
Levothyroxine (T4)Levothyroxine (T4)
Synthetic T4, the standard first-line treatment for hypothyroidism worldwide. Long half-life (~7 days) provides stable serum levels with once-daily dosing. Peripheral deiodination converts T4 to active T3.
Gold standard hypothyroid treatment
Stable serum levels
Once-daily dosing
Extensive safety data
No commitment · HSA/FSA eligibleNo commitment · HSA/FSA eligible
How it works
Mechanism of action
Replaces or supplements endogenous T4. Undergoes peripheral 5'-deiodination (primarily by DIO1 and DIO2) to T3, the biologically active thyroid hormone. Long half-life enables once-daily dosing.
The baseline panel.
Every Marek client receives this baseline panel before a provider review. Your provider may add additional biomarkers based on your health history, symptoms, and goals, pulling from 1,000+ available markers. See more biomarkers →
Hormone Profile
12 markers
Sex hormones
- Total TestosteroneLC/MS
- Free TestosteroneEquilibrium Dialysis
- Estradiol, Sensitive / UltrasensitiveLC/MS
- Sex Hormone Binding Globulin (SHBG)
- ProgesteroneLC/MSFemale panel
- Prolactin
- Luteinizing Hormone (LH)
- Follicle-Stimulating Hormone (FSH)
- hCG, Total, QuantitativeFemale panel, pre-menopause
Adrenals & neurosteroids
- Cortisol
- DHEA-S
Growth hormone / IGF-1
- Insulin-Like Growth Factor I (IGF-1)
Thyroid Status
3 markers
Thyroid hormones
- Thyroid Stimulating Hormone (TSH)
- Free T4
- Free T3
Heart Health
9 markers
Cardiovascular health
- Total Cholesterol
- HDL Cholesterol
- LDL Cholesterol
- LDL:HDL Ratio
- VLDL Cholesterol
- Triglycerides
- Apolipoprotein-B (ApoB)
- C-Reactive Protein, High Sensitivity (hsCRP)
- Lipoprotein(a) (Lp(a))
Metabolism
3 markers
Insulin sensitivity
- Blood Glucose
- Fasting Insulin
- HbA1c
Organ Function
26 markers
Liver & pancreas
- AST
- ALT
- Bilirubin, Total
- γ-Glutamyl Transferase (GGT)
Kidney function
- BUN
- Creatinine w/ eGFR
Comprehensive Metabolic Panel (CMP)
- Glucose
- Blood Urea Nitrogen (BUN)
- Creatinine
- eGFR
- BUN/Creatinine Ratio
- Sodium
- Potassium
- Chloride
- Carbon Dioxide, Total
- Calcium
- Protein, Total
- Albumin
- Globulin, Total
- Albumin/Globulin (A/G) Ratio
- Alkaline Phosphatase (ALP)
- AST
- ALT
Prostate health
- Prostate-Specific Antigen (PSA)Male panel
- Free PSAMale panel
- % Free PSAMale panel
Nutrient Status
31 markers
Vitamins & minerals
- Vitamin D, 25-OHD (25-Hydroxy)
- Magnesium, RBC
Iron status
- Iron
- Iron Saturation
- TIBC
- UIBC
- Ferritin
Complete Blood Count (CBC)
- White Blood Count (WBC)
- Red Blood Count (RBC)
- Hemoglobin (Hgb)
- Hematocrit (HCT)
- MCV
- MCH
- MCHC
- Red Cell Distribution Width (RDW)
- Platelets
- Neutrophils
- Neutrophils (Absolute)
- Lymphocytes
- Lymphocytes (Absolute)
- Neutrophil/Lymphocyte Ratio
- Monocytes
- Monocytes (Absolute)
- Eosinophils
- Eosinophils (Absolute)
- Basophils
- Basophils (Absolute)
- Immature Cells
- Immature Granulocytes
- Immature Granulocytes (Absolute)
- NRBC, w/ Reflex for Immature Cells
Clinical evidence
The research behind Levothyroxine (T4).
Safety profile
Monitoring & safety information.
Commonly reported side effects
- Palpitations (if overdosed)
- Anxiety
- Insomnia
- Hair loss (temporary)
Less common but serious risks
- Cardiac arrhythmias with excess
- Bone loss (chronic suppressive doses)
- Adrenal crisis if given without cortisol replacement in adrenal insufficiency
Generally not appropriate for
- Thyrotoxicosis
- Uncorrected adrenal insufficiency
Typical monitoring
- TSH every 6 to 8 weeks during titration, then every 6 to 12 months
- Free T4
- Heart rate
FAQ
Quick answers.
Synthetic T4, the standard first-line treatment for hypothyroidism worldwide. Long half-life (~7 days) provides stable serum levels with once-daily dosing. Peripheral deiodination converts T4 to active T3.
Gold standard hypothyroid treatment. Stable serum levels. Once-daily dosing. Extensive safety data. Inexpensive (generic).
Common side effects include: palpitations (if overdosed), anxiety, insomnia, hair loss (temporary). Most side effects are dose-dependent and may resolve with continued use or dose adjustment.
Synthetic T4, the standard first-line treatment for hypothyroidism worldwide. Long half-life (~7 days) provides stable serum levels with once-daily dosing. Peripheral deiodination converts T4 to active T3.
Treatments are dependent on licensed clinical prescription. Client costs vary based on individual labs and panel in treatments and services.