A study suggests that some people who take a popular weight-loss drug called semaglutide may lose more muscle than others, especially older adults and women.
The research also shows that eating more protein might help reduce this problem and protect muscle during weight loss.
The study was presented at ENDO 2025, the annual meeting of the Endocrine Society, held in San Francisco. This meeting often shares the latest research about hormones, metabolism, and diseases like diabetes and obesity.
Semaglutide is a medication used to help people lose weight. It works by copying the action of a natural hormone in the body called GLP-1. This hormone helps control appetite and digestion.
When people take semaglutide, they usually feel less hungry and eat less food. Their stomach also empties more slowly, which helps them feel full for a longer time. Because of this, many people can lose a significant amount of weight.
However, losing weight is not always simple. When people lose weight, they do not only lose fat. They can also lose muscle. Muscle is very important for the body. It helps people move, stay strong, and keep their balance. It also plays a key role in controlling blood sugar and keeping bones healthy.
The study was led by Dr. Melanie Haines from Massachusetts General Hospital and Harvard Medical School. She explained that losing too much muscle can have negative effects on health. It may lead to weaker bones, poorer blood sugar control, and a higher risk of frailty, especially in older adults.
In the study, researchers followed 40 adults with obesity over a period of three months. Out of these participants, 23 people were given semaglutide, while 17 people followed a structured lifestyle program called Healthy Habits for Life. This program focused on diet and healthy behavior changes rather than medication.
The researchers carefully measured how much weight each person lost and how much of that weight came from muscle, also called lean mass. The results showed that people taking semaglutide lost more weight overall compared to those in the lifestyle group. This is consistent with what doctors already know about the strong effects of this drug.
However, the study also found something important. In both groups, about 40 percent of the weight lost came from lean mass, including muscle. This means that muscle loss is a common part of weight loss, no matter how the weight is lost.
Even more importantly, the researchers found that some people were more likely to lose muscle than others. Among those taking semaglutide, women and older adults tended to lose more muscle. People who ate less protein also experienced greater muscle loss.
Protein is an essential part of the diet. It helps build and repair muscles and supports many important body functions. If people do not eat enough protein while losing weight, their bodies may break down muscle tissue for energy.
The study also showed that muscle loss could affect how well the body controls blood sugar. People who lost more muscle had smaller improvements in their HbA1c levels. HbA1c is a common test used to measure average blood sugar over several months. Lower HbA1c levels usually mean better blood sugar control.
This finding is important because semaglutide is often used not only for weight loss but also to help manage type 2 diabetes. If muscle loss reduces the improvement in blood sugar, it may limit some of the benefits of the treatment.
Dr. Haines suggested that increasing protein intake could be a simple and helpful strategy. By eating more protein, people may be able to protect their muscles while still losing fat. This could help them gain the full benefits of weight loss without the negative effects of losing too much muscle.
She also pointed out that more research is needed. Scientists still need to find the best ways to help people lose fat while keeping their muscle. This is especially important for women and older adults, who seem to be more at risk.
As weight-loss drugs like semaglutide become more widely used, understanding their full effects on the body is becoming increasingly important. While these medications can be very effective, it is clear that a balanced approach, including proper nutrition, is key to achieving the best health outcomes.
If you care about muscle, please read studies about factors that can cause muscle weakness in older people, and scientists find a way to reverse high blood sugar and muscle loss.
For more health information, please see recent studies about an easy, cheap way to maintain muscles, and results showing these vegetables essential for your muscle strength.
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