CONTROL Registry

Determine whether patients transitioned from levothyroxine tablet formulations to an alternate levothyroxine formulation achieve:

  • improved TSH control (vs. target TSH value)
  • improved hypothyroid symptom control
  • improved quality-of-life


  • Evaluation Period is 6 months post enrollment
  • Evaluation Criteria include:
    • Number of subjects achieving TSH within target range after therapy change
      • The time (and # of titration steps) required to achieve targeted TSH after therapy change
      • Patient’s overall satisfaction with therapy change

  • A multicenter, observational, longitudinal registry. Research protocol was IRB-approved
  • Patients followed for approximately 6 months from the time of transition from initial levothyroxine to alternate levothyroxine therapy. Patients expected to undergo clinical evaluation every 4-6 weeks
  • Patients must be ≥18 years with confirmed hypothyroidism and currently being treated with levothyroxine tablet therapy and who meet one or more of the following criteria:
    • Unable to achieve hypothyroid symptom control or to reach target TSH levels with initial therapy as documented by two T4/TSH tests in the prior 13 weeks (≤1 value can be at sub-therapeutic level)
    • Unable to tolerate initial therapy for one of the following reasons:
      • Diagnosis of celiac disease
      • Ongoing use of a PPI (patient reported)
      • H. pylori infection as confirmed by diagnostic testing
    • Willing to switch to an alternate levothyroxine therapy

  • Study conducted in geographically dispersed, community-based endocrinology practices
  • Patients serve as their own controls
  • Patients take alternate therapy daily for 6 months or as clinically indicated after transition

Study in progress

To learn more about a levothyroxine free of dyes, gluten(wheat starch), alcohol, lactose, and sugar, click here.