Navigating GLP-1 Use in Athletes: Balancing Metabolic Benefits With Performance Risks

Ahead of the Sports Pharmacy Summit, taking place April 10 and 11 in Fort Lauderdale, Florida, this preconference spotlight features insights from Jessica Beal-Stahl, PharmD, director of clinical services at Hobbs Pharmacy and a clinical sports pharmacist, on the evolving role of glucagon-like peptide-1 (GLP-1) receptor agonists in athletic populations. Drawing on clinical expertise and lived experience, this perspective highlights the balance between therapeutic benefit and potential performance-related risks.

This conversation has been lightly edited for clarity.

Jessica Beal-Stahl, PharmD: In my community pharmacy practice, I work closely with high school, collegiate, and masters athletes, and we have seen a significant rise in GLP-1 agonist use, particularly in the masters population. In some cases, these medications have been life-changing—improving metabolic parameters, reducing systemic inflammation, and helping women with PCOS [polycystic ovary syndrome], endometriosis, or weight-related osteoarthritis. When appropriately indicated and monitored, the impact can be profound.

However, I have also seen the other side—rapid weight loss in already-lean athletes, unintended lean mass loss, disrupted fueling patterns, and psychological strain related to appetite suppression. My perspective is also informed by personal experience; I struggled with an eating disorder in college and understand the complex relationship between food, performance, and identity in sport. That experience provides both empathy and caution when counseling athletes on medications that alter hunger and body composition.

Because of this intersection of sport, pharmacology, community practice, and lived experience, I approach GLP-1 use in athletes with both optimism and vigilance—recognizing therapeutic potential while remaining protective of metabolic resilience, mental health, and long-term performance sustainability.

Pharmacy Times: From your perspective, what are the most important clinical considerations when GLP-1s are used by athletes (eg, gastrointestinal adverse effects, hydration/electrolytes, energy availability, timing around training/competition)?

Beal-Stahl: The athletic cultural narrative is predictable: Lighter must mean faster; leaner must mean better. At present, there are no peer-reviewed trials directly examining the effects of GLP-1 agonists on athletic performance in trained populations. What we have instead is mechanistic reasoning, indirect clinical data, and emerging concern. In sport, absence of evidence is not evidence of safety.

One concerning [adverse] effect is changes in body composition and lean mass, including loss of muscle mass, especially if nutrition or protein intake is inadequate. For athletes, lean mass is not cosmetic. It is glycogen storage. It is force production. It is metabolic flexibility. It is endocrine signaling.

The most significant concern in athletic populations is not simply muscle loss—it is energy availability. GLP-1 agonists blunt hunger signaling. In sedentary populations, this facilitates caloric reduction. In athletes, hunger serves a protective physiological role. Hunger is not weakness. In athletes, it is data.

Blunted appetite can lead to inadequate pretraining fueling, reduced carbohydrate intake during prolonged sessions, insufficient postexercise protein intake, and chronic low energy availability. Low energy availability underpins the pathophysiology of Relative Energy Deficiency in Sport (REDs), characterized by impaired menstrual function, decreased bone density, altered thyroid function, suppressed metabolic rate, mood disturbance, and impaired recovery.

When pharmacologic appetite suppression is layered onto performance culture—particularly in female athletes and weight-sensitive sports—the risk profile shifts. Suppressing that signal without structured nutritional oversight risks unintended endocrine and musculoskeletal consequences.

Delayed gastric emptying, nausea, early satiety, reflux, and altered bowel patterns are among the most common adverse effects of GLP-1 therapy. In athletic settings, these are not minor inconveniences. Delayed gastric emptying may impair tolerance to precompetition meals, reduce carbohydrate oxidation during endurance events, or increase the risk of nausea or vomiting during high-intensity training or competition. Even mild, persistent nausea often leads to subconscious caloric restriction, further compounding energy deficits.

Reduced food intake combined with gastrointestinal adverse effects increases the risk of dehydration and electrolyte imbalance. For endurance athletes training in heat or high-volume blocks, this may impair thermoregulation, plasma volume expansion, and cardiovascular stability. Structured hydration planning becomes essential, as reliance on hunger and thirst cues may no longer be reliable.

Exercise-engaged populations already demonstrate higher vulnerability to appearance-driven behaviors and image-performance conflation. The availability of pharmacologic appetite suppression may reinforce disordered fueling patterns under the guise of optimization.

An athlete who fears hunger cannot trust her physiology. In female athletes, particularly, perfectionism, aesthetic pressure, and body surveillance are well-documented contributors to low energy availability. Clinical conversations must therefore extend beyond weight to include mental resilience, literacy, and body autonomy.

GLP-1 agonists play an important, evidence-based role in the management of metabolic disease. But in athletes—particularly those without metabolic pathology—the risk-benefit calculus changes.

Pharmacy Times: What role can pharmacists play in counseling athletes or patients who are highly active on safe use, risk mitigation, and avoiding inappropriate or nonmedical use?

Beal-Stahl: When I think about the pharmacist’s role in counseling highly active individuals—whether competitive athletes, tactical professionals, or simply high-performing individuals—I see our role as far more than medication experts. We are stewards of physiology.

In sport, medications are rarely neutral. They intersect with training load, recovery, endocrine balance, body composition, and psychology. When an athlete asks about using something—whether it’s a GLP-1 agonist, peptide, stimulant, or high-dose supplement—our responsibility is not simply to confirm that it’s “allowed” or “within dosing range,” but to contextualize risk within performance.

Highly active individuals often approach medications through a performance lens: How will this make me better, leaner, faster, or more efficient? But pharmacology doesn’t always align with performance goals—and in some cases, it can undermine them.

As pharmacists—especially in sports pharmacy and community practice—we are uniquely positioned to recognize that nuance. Slowing down and asking more insightful questions is critical. An athlete may present with a desire for weight loss, but deeper conversation often reveals a need for control or a response to external pressure, without full consideration of how weight loss may impair performance.

Risk mitigation starts with physiology literacy. When counseling on medications like semaglutide or tirzepatide, we must translate clinical data into athletic consequences. Smaller does not automatically mean better; underfueled and undermuscled athletes often perform worse, recover more slowly, and break down faster.

We also need to screen proactively for low energy availability and Relative Energy Deficiency in Sport. Appetite suppression layered onto high training volume can quietly drive endocrine disruption. Missing or irregular menstrual cycles, for example, are not benign—they are physiological feedback. Blunting that signal pharmacologically without structured nutritional support is not optimization; it is interference.

In community practice, we have a unique longitudinal view. We see refill patterns, body weight trends, [adverse] effect complaints, and questions about supplements between physician visits. That visibility allows us to intervene early, before small compromises compound into larger issues.

Avoiding inappropriate or nonmedical use requires clinical confidence. Exercise-engaged populations are at higher risk for appearance-driven decision-making and performance-enhancing experimentation. Social media has normalized pharmacologic appetite suppression and off-label performance strategies in ways that often lack clinical nuance.

Sometimes our role is to say what others won’t: There is no evidence that this improves performance in healthy athletes, and there is plausible evidence that it may impair it. We are not only protecting athletes from prohibited substances, but also from legal ones that may be misaligned with their physiology.

Ultimately, the pharmacist’s role is to reanchor the conversation to physiology, performance longevity, and health integrity—translating pharmacology into practical strategy, identifying risk, advocating for proper fueling, and helping normalize strength over smallness.

Pharmacy Times: Are there any red flags or situations where you’d strongly recommend closer monitoring or discontinuation (eg, rapid weight loss, dehydration risk, concomitant medications, history of eating disorders)?

Beal-Stahl: Yes, there are situations in which I would recommend closer monitoring, dose adjustment, or even discontinuation of GLP-1 receptor agonists. This is an important question because in athletes and highly active individuals, the threshold for “acceptable [adverse] effects” should be lower than in sedentary populations because performance, bone density, endocrine stability, and recovery are tightly linked to adequate energy availability, injury risk, performance, and lean mass preservation.

Rapid weight loss—particularly more than 1% to 1.5% of body weight per week—visible muscle loss, declining strength metrics, or recurrent soft tissue injury are red flags that lean mass may be disproportionately affected.

I am also highly cautious if I see signs of low energy availability or REDs, such as menstrual irregularities, persistent fatigue, mood changes, elevated resting heart rate, or recurrent illness. I feel that those with disordered eating or prior eating disorders need to be more closely screened and work with a team, as pharmacologic appetite suppression in this context can reinforce maladaptive patterns or distorted body images/pressures.

Appetite suppression in an athlete is not simply weight management; it is endocrine manipulation in a system already stressed by training. Seeing athletes on other appetite-suppressing drugs, such as stimulants, would make me want to have a deeper conversation and assess risks and plan ahead for the athlete before starting.

Significant gastrointestinal intolerance, inability to maintain hydration, orthostatic symptoms, or elevated creatinine would also prompt reassessment, particularly in endurance athletes training in heat.

Concomitant use of diuretics, SGLT-2 inhibitors, stimulants, or medications with narrow therapeutic windows warrants closer monitoring due to compounded dehydration or altered absorption risks.

For athletes, but also anyone, if the therapy begins to compromise muscle, bone, hormonal stability, or mental health, that is the moment to pause and recalibrate.