---
title: Identification of Non-responders to Levothyroxine Therapy
nct_id: NCT03627611
overall_status: COMPLETED
phase: PHASE2
sponsor: Oslo University Hospital
study_type: INTERVENTIONAL
primary_condition: Hypothyroidism
countries: Norway
canonical_url: "https://parkinsonspathways.com/agent/trials/NCT03627611.md"
clinicaltrials_gov: "https://clinicaltrials.gov/study/NCT03627611"
ct_last_update_post_date: 2021-03-17
last_seen_at: "2026-05-12T06:33:39.785Z"
source: ClinicalTrials.gov (mirrored, no enrichment)
---
# Identification of Non-responders to Levothyroxine Therapy

**Official Title:** A Randomized Crossover Study, Examining Differential Effects of Levothyroxine and Liothyronine

**NCT ID:** [NCT03627611](https://clinicaltrials.gov/study/NCT03627611)

## Key Facts

- **Status:** COMPLETED
- **Phase:** PHASE2
- **Study Type:** INTERVENTIONAL
- **Target Enrollment:** 69
- **Lead Sponsor:** Oslo University Hospital
- **Collaborators:** Hormonlaboratoriet, Spesialistsenteret Pilestredet Park
- **Conditions:** Hypothyroidism, Biomarkers, Endocrine System Diseases
- **Start Date:** 2018-08-14
- **Completion Date:** 2020-06-22
- **CT.gov Last Update:** 2021-03-17

## Brief Summary

The purpose of this study is to assess differential effects of T4 and T3 on cell and tissue level

## Detailed Description

15-20% of the patients with hypothyroidism remain symptomatic, despite adequate thyroxine substitution. Endocrinologists are split in their opinion on combination therapy with T4 and T3 on patients with poorly regulated hypothyroidism. There are no objective means, by which to identify individuals who would benefit from combination therapy. The purpose of this study is to assess differential effects of T4 and T3 on body temperature, metabolism, muscle strength and brain function. The main aim is to try to identify biomarkers reflecting different effects of T4 and T3 on cell and tissue level.

## Eligibility

- **Minimum age:** 18 Years
- **Maximum age:** 65 Years
- **Sex:** FEMALE
- **Healthy Volunteers:** No

```
Inclusion Criteria:

* Poorly regulated hypothyroidism
* Female aged between 18 and 65 years
* Written informed consent obtained from the patient according to national regulations

Exclusion Criteria:

* Cardiovascular disease
* Chronic liver disease
* Chronic kidney disease
* Any other endocrinological disease
* Use of beta blockers
* Pregnant or lactating females
* Hormonal substitution other than T3 and T4
* Known psychiatric disease
```

## Arms

- **T4** (ACTIVE_COMPARATOR)
- **T3** (EXPERIMENTAL)

## Interventions

- **Levothyroxin** (DRUG) — 3 months
- **Liothyronine** (DRUG) — 3 months

## Primary Outcomes

- **Brown adipose tissue activation** _(time frame: 6 months)_ — Thermal imaging of supraclavicular fossa

## Secondary Outcomes

- **Body temperature** _(time frame: 6 months)_
- **Energy expenditure** _(time frame: 6 months)_
- **Muscle strength** _(time frame: 6 months)_
- **ThyPRO Questionnaire** _(time frame: 6 months)_
- **Mean levels of thyroid hormones** _(time frame: 6 months)_
- **SF-36 Questionnaire** _(time frame: 6 months)_
- **Fatigue Questionnaire** _(time frame: 6 months)_
- **New biomarkers** _(time frame: 6 months)_
- **Micro-RNA, miR-92a** _(time frame: 6 months)_

## Locations (1)

- Oslo University Hospital, Oslo, Norway

## Recent Field Changes (last 30 days)

- `status.overallStatus` — added _(2026-05-12)_
- `status.primaryCompletionDate` — added _(2026-05-12)_
- `status.completionDate` — added _(2026-05-12)_
- `status.lastUpdatePostDate` — added _(2026-05-12)_
- `design.phases` — added _(2026-05-12)_
- `design.enrollmentCount` — added _(2026-05-12)_
- `eligibility.criteria` — added _(2026-05-12)_
- `eligibility.minAge` — added _(2026-05-12)_
- `eligibility.maxAge` — added _(2026-05-12)_
- `eligibility.sex` — added _(2026-05-12)_
- `outcomes.primary` — added _(2026-05-12)_
- `outcomes.secondary` — added _(2026-05-12)_
- `armsInterventions.arms` — added _(2026-05-12)_
- `armsInterventions.interventions` — added _(2026-05-12)_
- `sponsor.lead` — added _(2026-05-12)_
- `sponsor.collaborators` — added _(2026-05-12)_
- `results.hasResults` — added _(2026-05-12)_
- `locations.oslo university hospital|oslo||norway` — added _(2026-05-12)_

---

*Canonical: https://parkinsonspathways.com/agent/trials/NCT03627611.md*  
*Source data (authoritative): https://clinicaltrials.gov/study/NCT03627611*  
*This page is a raw mirror with no AI summary, no editorial enrichment, and no Parkinson's-specific filtering.*