BACKGROUND
Hypothyroidism is common and is diagnosed by thyroid blood tests. Overt hypothyroidism occurs when the TSH is high and the FT4 levels is low. Subclinical hypothyroidism happens when the TSH is high and the FT4 level is still normal. This condition affects about 4–10% of adults. It is more common in older adults, affecting about 15–20% of people over age 60. Hypothyroidism is treated by thyroid hormone replacement, most often with levothyroxine.

Levothyroxine remains one of the most frequently prescribed medications in the United States. Much of this increase in levothyroxine treatment likely is driven by treatment of subclinical hypothyroidism. However, research shows that many mild TSH increases in older adults are temporary and return to normal without treatment. Studies have also found that levothyroxine often does not improve common symptoms such as tiredness or high cholesterol in these patients. As a result, some people may be taking thyroid medicine without getting much benefit. Taking too much thyroid hormone can also increase the risk of atrial fibrillation (an abnormal heart rhythm) and bone loss.

This study looked at whether older adults could safely reduce or stop taking levothyroxine if done so in a planned and closely monitored way.

THE FULL ARTICLE TITLE
Ravensberg J et al. Discontinuation of levothyroxine in adults aged 60 years or older. JAMA. Epub 2026 Apr 6:e262864; doi: 10.1001/jama.2026.2864. PMID: 41941226

SUMMARY OF THE STUDY
The study included adults age 60 and older from 58 primary care practices in the Netherlands. Participants had been taking only levothyroxine at a stable dose of 150 mcg (μg) per day or less for at least one year. Their starting TSH level had to be below 10 mIU/L. People were not included if they had previously had their thyroid removed, received radioactive iodine treatment, had radiation to the neck, or were taking medicines that affect thyroid function.

Levothyroxine doses were lowered by 12.5 to 50 mcg at least every six weeks. Before each dose reduction, blood tests checked thyroid function. The dose was lowered only if the TSH stayed below 10 mIU/L and the FT4 level remained normal. Participants also had to agree before each dose change. The goal was to see how many people could completely stop levothyroxine while keeping normal thyroid function. The study included 370 people with an average age of 70.5 years, and 80% were women.

After one year:

• About one in four participants (95 people) stopped levothyroxine completely and still had normal thyroid function.
• About one in three reduced their dose by at least 50%.
• Nearly two-thirds of people taking 50 mcg per day or less were able to successfully reduce or stop their medication.

People who lowered or stopped their medication did not report worse thyroid symptoms, more fatigue, or a lower quality of life compared with the start of the study.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
The results suggest that many older adults taking levothyroxine may be able to lower their dose or stop the medication without causing harm. This may reduce the risk of side effects from taking too much thyroid hormone, such as abnormal heart rhythms and bone loss.

People taking lower doses of levothyroxine were the most likely to stop the medication completely. Even people taking higher doses were often able to safely reduce their dose. Anyone thinking about lowering or stopping levothyroxine should work closely with their healthcare provider. The dose should be reduced slowly, with regular blood tests and monitoring for symptoms.

The study followed participants for one year. Longer studies are still needed, but the results suggest that many older adults may continue to do well after reducing or stopping levothyroxine.

— Marjorie Safran, MD

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