Athletes and GLP-1s: What You Need to Know

WADA Status: Not Currently Banned

As of 2025, GLP-1 receptor agonists (semaglutide, tirzepatide, liraglutide) are not on the World Anti-Doping Agency Prohibited List. They are not classified as performance-enhancing drugs and are not subject to therapeutic use exemption (TUE) requirements.

That said, transparency matters. Athletes subject to drug testing should disclose all medications to their team physicians and anti-doping authorities, even for substances not on the prohibited list.

The Muscle Loss Problem for Athletes

The primary concern for athletes—especially those in power, strength, or team sports—is lean mass loss during GLP-1 therapy.

For a 100 kg athlete who loses 15 kg on semaglutide, approximately 4-6 kg of that loss is muscle. That's meaningful for sports where absolute strength matters.

Sport-Specific Considerations

Training Implications During GLP-1 Therapy

1. Energy Availability

GLP-1s create a significant caloric deficit—that's how they work. For athletes, this poses training challenges:

• Reduced glycogen stores: Lower carbohydrate intake can impair high-intensity training capacity
• Relative Energy Deficiency in Sport (RED-S): Severe caloric restriction can cause hormonal disruption, impaired immunity, and overtraining susceptibility
• Training adaptations: Muscle building is compromised in caloric deficit regardless of medication

2. Recovery Nutrition

Post-workout nutrition is critical for adaptation. GLP-1-induced appetite suppression makes this difficult:

3. Hydration

GI side effects (vomiting, diarrhea) can cause dehydration—dangerous for athletes, especially in heat. Monitor hydration status carefully during training and competition.

4. Timing Around Competition

Most sports medicine physicians recommend against active dose titration during competitive seasons. Options include:

• Off-season use: Use GLP-1s during off-season when training load is lower
• Maintenance dosing: If already stable on GLP-1, continue at current dose rather than increasing
• Competition pause: Some athletes pause medication 2-4 weeks before major competitions to allow appetite normalization

Strategies to Preserve Performance

Resistance Training is Non-Negotiable

Athletes on GLP-1s should maintain or increase resistance training volume. This is the most effective intervention for preserving lean mass during weight loss.

Protein Intake Strategies

When appetite is suppressed, prioritize protein-rich foods first. Use whey protein shakes as needed—liquid calories are often easier to consume when appetite is low.

Slower Titration for Athletes

The standard 4-week titration schedule may be too aggressive for athletes who need to maintain training. Consider:

• 6-8 weeks at each dose level
• Stopping at lower maintenance doses (e.g., 1.0mg semaglutide instead of 2.4mg)
• Prioritizing body composition over scale weight

Body Composition Monitoring

Athletes should track more than scale weight during GLP-1 therapy:

• DEXA scans: Gold standard for tracking lean mass vs fat mass changes
• Strength metrics: Track key lifts to detect performance decline
• Body circumference: Waist, hip, chest, arm, thigh measurements
• Performance testing: Sport-specific metrics (sprint times, power output, VO2max)

If lean mass is declining faster than acceptable, consider reducing GLP-1 dose, increasing protein intake, or pausing therapy.

What Professional Athletes Are Doing

Anecdotally, GLP-1 use is increasing among professional athletes, particularly in:

• Retired athletes struggling with post-career weight gain
• Off-season weight management in weight-conscious sports (jockeys, wrestlers, boxers)
• Linemen in American football managing long-term health after playing career
• Endurance athletes seeking incremental power-to-weight improvements

Few active elite athletes have publicly discussed GLP-1 use during competitive careers, though this may change as medications become more normalized.

Recreational Athletes: Different Calculus

For recreational athletes—weekend warriors, masters competitors, fitness enthusiasts—the considerations differ:

For a 45-year-old recreational runner with obesity, losing 15 kg (even with some muscle) may dramatically improve running enjoyment, reduce knee pain, and reduce cardiovascular risk—worth the performance tradeoffs.

When to Avoid GLP-1s as an Athlete

GLP-1 therapy is likely not appropriate for athletes who:

• Are in competitive season with upcoming major events
• Have a normal or near-normal body composition (not medically indicated)
• Compete in weight classes and are at risk of losing strength advantage
• Have history of eating disorders (GLP-1s require medical supervision in this population)
• Cannot tolerate reduced caloric intake during training
• Are unwilling to maintain resistance training during therapy