An international team of researchers warns that hundreds of thousands of patients might be unnecessarily taking prescription drugs to treat thyroid problems.

The researchers analyzed data from 21 trials that involved a total of 2,192 participants, most of whom are over the age of 65. They found that those who have subclinical hypothyroidism do not appear to gain any benefit from hormone therapy.

They published the study in The BMJ on Tuesday, May 14.

Hypothyroidism Being Overtreated

Hypothyroidism, or mild underactive thyroid problem, occurs when the thyroid glands do not produce enough thyroid hormones to meet the body's needs. The thyroid hormone controls how the body uses energy and affects every organ, including the heart.

People who have the disease might experience weight gain, joint and muscle pain, constipation, slow heart rate, thinning hair, depression, goiter, and others.

Hypothyroidism affects one in 20 people. The disease is more common among older adults and women.

Patients diagnosed with hypothyroidism are often prescribed lifelong daily pills that would replace their missing thyroid hormone.

However, the researchers found that medication that the drugs rarely improve symptoms of hypothyroidism such as weight gain, low mood, and tiredness. They said that almost all adults diagnosed with subclinical hypothyroidism will not see any benefit from taking the daily pills.

Lifelong Treatment Is Not For Everybody

The researchers noted that in the United Kingdom, the current guidelines acknowledge that some patients with hypothyroidism might not need treatment. However, they added that trying daily pills might be worthwhile.

The researchers argued that taking lifelong daily pills and attending check-ups could be burdensome, especially if it would not ease symptoms of the disease.

"It can be reasonable to try the tablets for a few months and see how the patient feels," said Mark Vanderpump of the Society for Endocrinology to the BBC. "You do not have to commit someone to lifelong treatment."

"Thyroid disease is being overtreated currently but it's premature to make a recommendation not to treat young people on the basis of the available evidence," added Simon Pearce of Newcastle University. "Some will feel better on treatment."

Despite their findings, the researchers stressed that patients should not stop taking their medication. They should first consult with their doctors at their next routine medication review before making any changes on their own.