New Issue: Science’s Impossible Questions. Read Now

Novel Thyroid Hormone Treatment Could Help Shed Pounds

Join Our Community of Science Lovers!


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


Some 31 million Americans are currently considered obese. Despite increasing public awareness of the problem, the number of people suffering from obesity is on the rise and scientists continue to search for safe and effective pharmaceutical treatments. To that end, findings published online this week by the Proceedings of the National Academy of Sciences could help. Researchers report the discovery of a chemical that selectively stimulates a thyroid hormone in animals without the deleterious side effects that similar therapies have.

Previous research had shown that administering thyroid hormones can speed metabolism, lower cholesterol levels and bolster weight loss. But unwanted side effects, particularly rapid heartbeats, often accompany the procedure. Gary Grover of Bristol-Myers Squibb and his colleagues investigated the two hormone receptors involved in mediating these effects, TR-beta and TR-alpha. They found that mice lacking the TR-alpha receptor experienced a much smaller heartbeat increase than control animals did in response to thyroid hormones. The other effects, such as lowered cholesterol and increased metabolism were similar between both groups.

The team next administered a chemical known as KB-141, which stimulates only TR-beta, to normal mice, rats and monkeys. Animals in all three groups exhibited decreased cholesterol levels and weight loss without increased heart rate. Although the findings are very preliminary, the authors conclude that KB-141 and related compounds "may offer several types of therapeutic potential and are candidates for further exploration."

Subscribe to Support Independent Journalism

Great science journalism requires human expertise, time, effort and creativity. And it costs money. That’s why I and the journalists here at Scientific American hope you’ll join our community.

When you subscribe, you are supporting staff and freelance journalists who are passionate about telling science stories that are true, important and compelling. Our editors and reporters are often experts in their fields, which means they understand the nuances of big discoveries and can untangle the breakthroughs from the hype. With a subscription, you are also supporting rigorous fact-checking to ensure the words we publish are precise and accurate. And you’re supporting original illustrations, graphics and photos that bring you closer to an advanced laboratory, an ice sheet in Antarctica or a space mission in orbit. You’re helping us craft other types of high-quality journalism as well: Our newsletters are carefully written, edited and curated by staffers you have or will come to know and love. Our Science Quickly podcast is based on original reporting, collaboration with editors and scientists and exacting production.

Subscriptions keep this engine running so we can continue to deliver thoughtful, rigorous and independent science journalism to you. In an era of viral misinformation, this work is crucial. If you value what we do, I hope you’ll consider joining us as a subscriber

Thank you,

Jeanna Bryner, Editor in Chief, Scientific American

Subscribe