Lighter but weaker? The hidden costs of Ozempic and weight-loss drugs for endurance athletes

Ozempic and other semaglutide medications have skyrocketed in popularity as weight-loss aids, with prescriptions surging by over 300% in the past year alone. Developed as a treatment for managing Type 2 diabetes, these medications have become household names in health and wellness circles as well. You may even know someone who's currently taking it—whether it's to control their blood sugar, shed a few pounds before their wedding or help slim down before the racing season.

Ozempic (semaglutide) is part of a class of medications known as GLP-1 receptor agonists, which were developed to help manage blood glucose levels in people with diabetes. Ozempic received FDA approval in 2017 and has since surged in popularity due to its weight-loss benefits, even among non-diabetic individuals. Ozempic works by mimicking the GLP-1 hormone, which regulates appetite. It suppresses appetite, slows gastric emptying and promotes feelings of fullness, often leading to reduced calorie consumption. When a person burns more calories than they consume, they are in a calorie deficit, which results in weight loss.

While these medications offer substantial health benefits for those who truly need them—such as managing Type 2 Diabetes or achieving significant weight loss when other methods have failed—their widespread adoption, now extending into endurance sports communities, raises an important question: are they safe for active individuals? Can Ozempic be a tool to help you achieve or maintain race weight?

Not all weight loss is the same

When we turn our focus to endurance athletes—such as long-distance runners, cyclists and triathletes—we know that high levels of energy are essential to compete and perform optimally. Achieving this depends heavily on proper nutrition, combined with muscular endurance, consistent training and adequate recovery.

Dr. Xavier Collazo, a DPT specialising in sports performance and rehabilitation at Tampa Bay Performance Physical Therapy, emphasises that the benefits of GLP-1 drugs must be carefully balanced against the potential risks, particularly for athletes.

“While these effects can be beneficial to those dealing with high BMIs or obesity, the endurance athlete, who requires large energy sources to perform and compete, will typically find that these effects would decrease performance to a degree,” he says.

“Not to mention the fact that when you lose weight, you do lose muscle, which is the driving force of all our movement."

In cycling, it’s long been believed that losing weight improves one's power-to-weight ratio a.k.a watts per kilogram. Thus, GLP-1 medications may seem like an appealing tool at first glance. However, these medications can cause muscle loss, which may negatively impact both your watts per kilogram and overall body composition. As a result, while the number on the scale might go down, your power output may decline alongside it.

The Risk of Under-fueling

Nutrition is a cornerstone of both performance and recovery. Protein is essential for muscle repair and growth, carbohydrates fuel energy needs, and healthy fats support brain function. With suppressed appetite comes the risk of under-fueling and potentially disrupting the body’s recovery processes, ultimately leading to a decline in performance.

Cycling demands a high caloric intake to sustain intense training and support recovery. The concern with Ozempic lies in its potent appetite-suppressing effects, which could cause one to unintentionally underfuel. This reduction of caloric intake can hinder the recovery process and increase the risk of overtraining and injury.

The Great Unknown

As GLP-1 medications become more widely used, research on their long-term effects is still in its early stages. With mass production and distribution relatively recent, there is much we have yet to understand about their broader implications.

“For now, in my personal opinion, I’d advise athletes to stick to more conventional methods of weight loss, working with nutritionists, dieticians, or simply structuring their training and intake better,” says Collazo.

“We know this will provide the best, natural result without the side effects of potential muscle loss, GI disturbance, and other long-term side effects that we are unaware of.”