What is the issue?

Some people with heart failure have low levels of the thyroid hormone, triiodothyronine (T3).  T3 helps regulate how the body's cells use energy and plays an important role in heart function. People with heart failure who have low T3 levels often experience poorer health outcomes and may find physical activities more difficult.

Chief Investigator, Dr Salman Razvi, from Newcastle University explains:

'Low T3 levels are common in people with heart failure and are consistently associated with poorer symptoms, reduced exercise capacity and worse long-term outcomes.'

What is the aim of the study?

The trial aims to find out whether giving T3 tablets to people with heart failure and low T3 levels can improve their ability to exercise, symptoms, quality of life and heart function.

Dr Salman Razvi continues: “We still do not know whether correcting low T3 can improve patients' symptoms, quality of life and heart function.

“The T3-HF trial is the first large UK study designed to answer this important question and could potentially open up a completely new treatment approach for a substantial group of patients living with heart failure."

Why is this study needed?

Although low T3 levels are common in people with heart failure, it is not yet known whether giving T3 treatment improves symptoms or heart function. This study has been designed to answer that question safely and scientifically before any wider use of T3 treatment can be recommended.

What is the trial called?

‘Triiodothyronine treatment in patients with heart failure and low T3 levels.’

How will the trial work?

258 people with heart failure and low T3 levels will take either T3 tablets or placebo (dummy) tablets twice a day for 24 weeks.

This is a randomised double-blinded, placebo-controlled trial. This means half of the people will be given T3 tablets and the remaining half will be given a placebo. Participants will be randomly allocated to either the T3 tablets or dummy tablets, and will not be aware which kind they are being treated with.

Researchers will ask the participants about their physical activity levels, quality of life and heart function at the start and end of the trial.

After 12 weeks of taking the tablets, researchers will contact the participants to see how they are getting on and whether they have experienced any side effects.

This will help researchers assess whether taking T3 tablets over 24 weeks improves exercise capacity, symptoms, quality of life and heart function.

Where will trial run?

The 258 patients will be recruited from across 14 UK hospitals once the trial is open.

Who is the trial for?

The trial will be open to adults with heart failure with reduced ejection fraction (HFrEF) who have low T3 levels and no evidence of an untreated thyroid disorder.

Who isn’t the trial for?

People with existing thyroid diseases such as hypothyroidism or hyperthyroidism or on medications that could affect T3 levels such as amiodarone or lithium are not eligible.

How is the trial being funded?

The study is funded by the National Institute for Health and Care Research (NIHR) through its Efficacy and Mechanism Evaluation (EME) Programme. The study is sponsored by Newcastle upon Tyne Hospitals NHS Foundation Trust.

How are patients involved?

People with either heart failure, thyroid conditions or both have been involved in the study design to advise the trial team on trial design and patient resources, including the animation video. Two members of the public are part of the trial management group and another member of the public is on the trial steering committee.

How can I find out more?

We anticipate the trial will begin recruiting participants in late 2026.

Once the trial is open, we will share information about trial sites, full eligibility criteria, how patients can take part, trial updates and patients’ experiences of taking part in the study.