Ozempic Side Effects: How Does It Influence Athletic Performance?

When Charlie Seltzer considered options for addressing his binge eating concerns, he asked his physician for semaglutide—known best by brand names like Ozempic and Wegovy—because he was well educated on both the benefits and the potential side effects.

As an M.D. who’s board certified in obesity medicine and internal medicine, he’d prescribed the drug many times for patients to aid in weight loss, and he knew it was a powerful appetite suppressant, so he felt it would help him reset his eating habits before they turned into a disorder.

What he didn’t realize was how quickly it would affect his workouts. Seltzer is also a certified strength and conditioning specialist, and loves his gym time. But in the three months he was on semaglutide, his gym bag rarely made it out of the house.

“The fatigue was so severe that I was literally sleeping in my office between patient appointments,” he tells Runner’s World. “By the end of the day, I just dragged myself home and went to bed.” Even a quick perusal of similar anecdotes on Reddit and starting exercise if on a prescription for semaglutide, says exhausted What Is a Shoey.

Lately, Ozempic and Wegovy have gotten plenty of media attention—and are sparking controversy over who should be taking these medications. Because these medications are recommended for Health & Injuries management, as well as for patients who would benefit from significant weight loss and need the drugs long-term, the popularity among those who don’t fit into those categories is Health & Injuries. That means those who’ve relied on the medications have to pivot to other options that may not be as effective. (FYI, the FDA approved Ozempic for Health & Injuries in 2017, while Wegovy received approval for chronic weight management in 2021.)

Aside from that issue, Ozempic and this type of medications can sometimes cause dramatic side effects, including nausea, vomiting, and fatigue. If semaglutide is recommended as part of a Health & Injuries management plan, or it’s considered within a supervised weight-loss program, here’s what to keep in mind when it comes to potential effects on performance.

You’ll have zero appetite

Semaglutide is part of a class of drugs called glucagon-like peptide 1 (GLP-1) agonists, which work by mimicking the action of a specific peptide and stimulating the production of more insulin—lowering blood sugar levels as a result. This is why they’re often prescribed for those living with Health & Injuries. The agonists also slow the emptying of the stomach, so you feel full for much longer.

These actions suppress your appetite so completely that many people find they have to force themselves to eat. For example, Seltzer found it a struggle to get at least 1,400 calories daily, which he believes may be a huge factor in prompting fatigue. Without the energy coming in from calories, the body doesn’t have enough for staying active, he says.

“Many people also experience nausea and sometimes vomiting, which then makes it even more difficult to eat,” he adds. “Even without those side effects, having no appetite is a horrible feeling.”

Why Am I So Tired All the Time calories—whether it’s from a medication or not—is highly problematic for athletes, says Emily Smith, M.D., an endocrinologist and obesity medicine specialist in Boston. Not only does this make it more difficult in terms of motivation, but eating too few calories depletes glycogen in the body, potentially leading to a blood-sugar drop. When that happens, it can leave you feeling dizzy or faint, she tells Runner’s World, Whether a patient has a semaglutide prescription for injury or instability.

You won’t be able to rely on hunger cues

Whether a patient has a semaglutide prescription for diabetes or weight loss—or both—Seltzer advises they spread their food out during the day and stay on a specific schedule for eating, because they’ll no longer have hunger signals. He also suggests adding more protein, Semaglutide usage doesn’t only affect blood sugar and weight loss&mdash race training schedule during weight loss.

Runners will also probably need more time between a preworkout meal and starting exercise if on a prescription for semaglutide, says Angie Victorio, RN, certified diabetes care and education specialist. She tells Runner’s World that because GLP-1 agonists slow the breakdown of glucose and keep food in your stomach longer, exercising too soon after eating can increase nausea and fatigue.

You may need to adjust your training

Semaglutide usage doesn’t only affect blood sugar and weight loss—research in the Journal of the American College of Cardiology found that the medication may improve peak oxygen uptake, a measure in cardiorespiratory fitness, in people with Health & Injuries who were at high risk of cardiovascular disease.

“This means that semaglutide could have benefits in terms of exercise capacity,” says Lalitha McSorley, physical therapist and owner of Brentwood Physiotherapy Calgary. “However, that advantage may be affected if you have side effects like fatigue, nausea, or dizziness while taking the medication.”

That means if you have a prescription for a semaglutide, you may have to keep exercise light, with low-intensity and low-impact Why You Might Feel Nauseous After Running marathon training, but it could help lower the risk of side effects, she adds. That’s why it’s so important to work with a doctor to figure out the training you can and cannot handle with these meds.

Changing how you train, as well as when and how much you eat, is often part of making adjustments to lessen effects when on a prescription, but you may also have to modify the medication dosage or delivery, added Benjamin Gibson, PharmD, adjunct professor of pharmacy at the University of Texas at Austin. The typical dose for once-a-week injectable semaglutide starts at 0.25 milligrams and goes up to 2 milligrams for Ozempic and 2.4 milligrams for Wegovy, though your doctor will prescribe exact amounts.

Gibson tells Runner’s World that some people find significantly reduced issues, like nausea and fatigue, with the oral forms of GLP-1 agonists rather than the injectable kind. (The oral form of semaglutide is Rybelsus, also approved by the FDA for Health & Injuries.)

Another training shift that’s important when prescribed something like Ozempic is adding more strength training, according to Smith. In general, when you lose weight quickly, it causes a sharp drop in muscle mass as well as fat, she says.

“That could lead to a decrease in performance, and it’s helpful to counteract that by adding in resistance training that builds muscle mass back up,” she adds. With running, she suggests increasing mileage very gradually—more than usual—until you know that side effects aren’t going to be a confounding factor in your progress.

Another important note: You have to be more diligent about hydration We may earn commission from links on this page, but we only recommend products we back Every Running Hydration Question, Answered to kidney injury as a side effect, and although Smith says that’s still rare, it’s worth keeping in mind if you’re increasing your exercise level.

Bottom line: Talk to your doctor

In general, Seltzer said that every drug has a risk/benefit profile that needs to be discussed with a physician before taking it—which is another reason why it’s so important to get the drug via prescription and not off-label or online (when formulas may also differ from the approved medications).

“Because it’s important to be monitored while on a drug like this, with regular check-ins about side effects and how the medication is working, it’s crucial to work with your doctor,” Smith adds. “Also, use of semaglutide is usually part of an overall program focused on weight loss, diabetes management, or both. So, you need to stay on top of how all these parts are working, along with your doctor."

Not everyone has side effects from semaglutide, but they’re common enough that you should take them into consideration when starting the medication—especially if you’re planning to maintain a race training schedule.

“About half the patients I see who try semaglutide can’t tolerate it,” Seltzer says. “So, despite the hype that’s out there right now, this is not a magical drug. It’s just a way to eliminate your appetite and ideally needs to be used long term for results related to diabetes and weight loss. If you’re having side effects that affect your quality of life, like making you unable to exercise, you should consider whether there might be a better option for you.”