GLP-1 for Athletes FAQ: 30 Questions Answered

This page answers the 30 most common questions athletes ask about GLP-1 medications. Each answer draws on published research and my personal experience as a competitive endurance athlete using GLP-1 (tirzepatide/Mounjaro). For the full story, start with my GLP-1 journey pillar page.

Getting Started

What is GLP-1 and how does it work for weight loss?

GLP-1 (glucagon-like peptide-1) receptor agonists are injectable medications that mimic a natural gut hormone. They reduce appetite by acting on brain receptors that control hunger and satiety, slow gastric emptying so you feel full longer, and improve insulin sensitivity. The two most prescribed are semaglutide (brand names Ozempic and Wegovy) and tirzepatide (Mounjaro and Zepbound).

For athletes, the relevant mechanism is appetite suppression combined with improved metabolic signaling. You eat less because you genuinely feel less hungry — not because you are white-knuckling a calorie deficit. This makes GLP-1 fundamentally different from traditional dieting, where willpower eventually runs out.

Who prescribes GLP-1 for athletes?

Any licensed physician can prescribe GLP-1 medications, but the quality of care varies. Endocrinologists and obesity medicine specialists understand the pharmacology best. Sports medicine doctors understand training demands best. Ideally, you want a provider who understands both — but that combination is rare.

Telehealth weight-loss clinics offer convenience but often follow a one-size-fits-all protocol. If you train 10+ hours per week, you need a prescriber who will consider your fueling requirements and adjust dosing accordingly, not just titrate to the maximum dose.

How much does GLP-1 cost per month?

Brand-name semaglutide (Wegovy) lists at $1,300-1,400/month. Tirzepatide (Zepbound) runs $1,000-1,100/month. Insurance coverage has expanded significantly — many plans now cover these medications with a qualifying BMI (30+ or 27+ with comorbidities).

Compounded semaglutide from specialty pharmacies costs $200-400/month and is legal in most jurisdictions while brand-name supply shortages persist. Athletes using microdoses spend even less because the supply lasts longer.

Is GLP-1 safe for endurance athletes?

GLP-1 medications have been studied in clinical trials involving over 30,000 patients. The safety profile is well-established for the general population. For athletes specifically, the concerns are practical rather than pharmacological: can you eat enough to fuel training? Will GI side effects disrupt your sessions? Will you lose too much lean mass?

There is no evidence that GLP-1 causes harm to the cardiovascular, musculoskeletal, or metabolic systems in healthy athletes. In fact, the STEP-HFpEF trial showed cardiovascular benefits. Monitor bloodwork regularly and work with your physician.

How quickly will I see results?

Appetite reduction is typically noticeable within 1-2 weeks. Scale weight usually begins dropping by week 2-4. On my protocol — tirzepatide 2.5mg/week — I went from 94.5kg to approximately 90kg at measurement over 5 weeks, with body fat moving from 13.0% to 11.3%. The rate depends on starting weight, dose, and training load. Slower loss preserves more lean mass — do not rush the process.

Training on GLP-1

Can I maintain high training volume?

Yes. GLP-1 does not impair cardiovascular function, muscle contractility, or aerobic capacity. The challenge is entirely nutritional — you need to eat enough to support your training even when you are not hungry. Athletes who plan meals by the clock rather than by hunger signals maintain full volume.

The adjustment period during the first 2-3 weeks of each dose increase is the hardest. Some athletes reduce training intensity (not volume) during these windows. By week 4 at a stable dose, most report normal training quality.

Does GLP-1 affect VO2max?

GLP-1 does not directly affect absolute VO2max (L/min). However, weight loss improves relative VO2max (ml/kg/min) because you are dividing the same aerobic output by a lower body mass. For a runner, this translates directly to improved running economy and faster paces at the same heart rate. A 5% weight loss with maintained fitness can yield a 3-5% improvement in race pace at equivalent effort.

How does GLP-1 affect strength training?

GLP-1 does not impair strength directly. The risk is indirect: appetite suppression leads to under-eating, which leads to inadequate protein, which leads to muscle loss. The solution is resistance training 2-3x per week and aggressive protein targeting (1.8-2.4g/kg/day). Athletes who maintain both typically preserve strength within 5-10% of pre-GLP-1 levels during the weight loss phase.

When should I inject relative to training?

Inject on your rest day or easiest training day. GLP-1 medications (both semaglutide and tirzepatide) peak in blood concentration around 24-72 hours post-injection, which is also when side effects are strongest. I inject tirzepatide on Friday evenings. Evening timing means I sleep through the initial peak, and by Saturday morning I feel normal for my long sessions. Pick a consistent day and time each week — consistency matters more than optimization.

Will I have low energy during training?

Some athletes report lower perceived energy in the first month, but this is usually attributable to under-fueling rather than a direct pharmacological effect. GLP-1 does not deplete glycogen stores or impair mitochondrial function. If you feel flat during training, the first thing to check is whether you ate enough in the previous 24 hours. Proactive fueling — eating by schedule, not by hunger — resolves this for most athletes within 3-4 weeks.

Racing on GLP-1

Should I stop GLP-1 before a race?

For short races (5K-half marathon), most athletes continue their normal protocol since fueling demands are manageable. For marathon and Ironman, some athletes skip their injection 1-2 weeks before race day to normalize gastric emptying. This is a personal decision based on how significantly GLP-1 affects your ability to absorb race nutrition. Practice your exact race nutrition protocol in training to know whether you need to adjust.

How does race day fueling change?

GLP-1 can slow gastric emptying, which may delay carbohydrate absorption during exercise. Key adaptations: start fueling earlier, prefer liquid calories over gels, and use smaller, more frequent doses. That said, the impact varies by medication and dose. On tirzepatide 2.5mg, I have had zero issues absorbing 100+ grams of carbohydrates per hour on the bike. Do not assume you will have problems — test your exact race nutrition protocol in training and adjust only if needed. For the full protocol, see my race day fueling guide.

Can I run a marathon on GLP-1?

Yes. The improved power-to-weight ratio from weight loss often more than compensates for any fueling adjustments. The non-negotiable requirement is testing your race nutrition plan in at least 3-4 long training runs. Do not try anything new on race day. On GLP-1 (whether semaglutide/Ozempic or tirzepatide/Mounjaro), the fundamentals do not change — practice everything first. See my race results for data.

What about triathlon and Ironman?

Triathlon is the most complex discipline for GLP-1 athletes because of the duration and multi-sport fueling demands. The bike is your primary fueling window — and also where GI issues from GLP-1 tend to be worst (aero position, vibration, heat). I am racing IM 70.3 Da Nang on May 10 and Challenge Roth on July 6, both on tirzepatide. My approach: Friday evening injection timing, 100+ grams of carbs per hour on the bike with liquid nutrition, and thorough testing of every race-day element in training first.

Does GLP-1 affect HYROX performance?

HYROX races last 60-90 minutes for competitive age-groupers, making fueling demands moderate. A pre-race meal and one mid-race gel is usually sufficient. The weight loss benefits are significant — every station in HYROX (running, sled push, sled pull, wall balls, lunges) benefits from lower body weight. GLP-1 athletes often see their biggest HYROX improvements not from aerobic gains but from carrying less weight through the workout stations.

Body Composition

How much muscle will I lose?

Without intervention, clinical data shows 25-40% of weight lost on GLP-1 is lean mass. The medication matters: tirzepatide shows approximately 75% fat / 25% lean mass loss versus semaglutide's roughly 60% fat / 40% lean mass. With proper intervention — resistance training, protein at 1.8-2.4g/kg/day, maintained training load — athletes can do better than these averages. My circumference measurements on tirzepatide show stable thigh and arm measurements while waist dropped 2cm and belly dropped 3.5cm, and my FTP improved from 261W to 281W. Track your body composition data and see my muscle preservation protocol.

How much protein do I need?

I target 140-190g of protein per day, which works out to roughly 1.6-2.1g/kg at my current weight. This is higher than general recommendations because you are simultaneously losing weight and training hard. Spread protein across 4-5 meals for optimal absorption. When appetite is low, protein shakes, Greek yogurt, and cottage cheese are efficient sources. On GLP-1 (whether semaglutide/Ozempic or tirzepatide/Mounjaro), protein is the single most important macronutrient to protect. Prioritize it at every eating occasion.

Should I get DEXA scans?

DEXA is the gold standard for body composition tracking and costs $50-150 per scan. If accessible, get a baseline before starting GLP-1 and scan every 8-12 weeks. I do not use DEXA — I track weekly circumference measurements (waist, belly, hips, thighs, arms) alongside body fat estimates and power data. This combination tells me where the loss is happening. If your limb measurements hold steady while your trunk measurements decrease, you are losing fat where you want to. If limbs are shrinking too, investigate your protein intake and resistance training volume.

What is the optimal body fat for racing?

Competitive age-group targets: 8-15% for men, 16-23% for women. I went from 13.0% to 11.3% on my GLP-1 protocol, which puts me in a good range for Ironman-distance racing — low enough for meaningful power-to-weight improvement (2.76 to 3.04 W/kg), high enough to maintain immune function and recovery. Going below 8% impairs health for most athletes. Use your data to find your optimal range rather than chasing arbitrary numbers.

How fast should I expect to lose weight?

Target 0.5-1% of body weight per week for optimal lean mass preservation. For reference, I went from 94.5kg to approximately 90kg over 5 weeks on tirzepatide 2.5mg — roughly 0.9kg per week, which is close to 1% at my starting weight. My power output improved simultaneously (FTP 261W to 281W), suggesting the loss was primarily fat. If you are losing faster than 1% per week with declining performance, your caloric deficit may be too aggressive.

Side Effects

What are the worst side effects for athletes?

The three most commonly reported for endurance athletes: (1) reduced appetite making it hard to hit daily calorie and protein targets, (2) nausea during exercise disrupting training quality, and (3) delayed gastric emptying interfering with race nutrition absorption. My experience on tirzepatide 2.5mg was excellent — only first-injection nausea, which resolved once I switched to Friday evening timing. Side effect severity varies by medication and dose. GI symptoms affect 40-50% of users in the first month but resolve for most within 6-8 weeks. For the full management protocol, see my side effects guide.

Can it cause nausea during exercise?

Yes, especially during the first month and during high-intensity sessions. The delayed gastric emptying means food sits in your stomach longer — and vigorous exercise with a full stomach is a recipe for nausea. Wait 2-3 hours after eating before intense exercise, favor liquid pre-workout nutrition, and reduce intensity during the initial adjustment period. Most athletes find exercise-related nausea resolves within 4-6 weeks at a stable dose.

How long do side effects last?

Most GI side effects peak 24-72 hours after injection and are most intense during the first 4-8 weeks of treatment. Each dose increase restarts the adjustment period for 2-3 weeks. By month 3 at a stable dose, most athletes report minimal ongoing side effects. Approximately 5-10% of users experience persistent symptoms that do not resolve, which usually indicates the dose is too high. Dose reduction or switching to microdosing resolves this for most.

How do I manage GI issues while training?

Eat smaller, more frequent meals. Favor liquid calories when solid food is unappealing. Avoid high-fat and high-fiber foods before training. Inject on rest days. Keep a food-symptom diary. Use ginger chews or peppermint tea for mild nausea. Reduce portion sizes rather than skipping meals entirely. If symptoms persist beyond 8 weeks, discuss dose adjustment or switching medications with your physician. Do not suffer in silence — there are options.

Can I drink alcohol on GLP-1?

Most athletes find alcohol tolerance drops significantly on GLP-1. The medication slows alcohol absorption, leading to unpredictable intoxication levels. Combined with the already- negative effects of alcohol on training recovery, sleep quality, and body composition goals, most competitive athletes on GLP-1 substantially reduce or eliminate alcohol. This is not a medical prohibition — it is a practical reality that most athletes discover quickly.

Regulations and Ethics

Is GLP-1 banned by WADA?

No. As of 2026, GLP-1 receptor agonists are on WADA's Monitoring Program but are not on the Prohibited List. They are legal in and out of competition. No Therapeutic Use Exemption (TUE) is required. WADA is collecting data and could reclassify them in future years. For the full regulatory analysis, see my WADA and ethics page.

Would it show up on a drug test?

Standard anti-doping panels do not test for GLP-1 receptor agonists because they are not prohibited. If WADA were to ban them, detection methods would need to be developed and validated. Semaglutide has a 7-day half-life, meaning it would be detectable for several weeks. Currently, there is no testing and no risk of a positive result for GLP-1 use.

What are the rules for age-group competition?

Age-group athletes in WADA-signatory sports follow the same prohibited list as professionals. Since GLP-1 is not prohibited, it is legal at all competition levels. HYROX has no anti-doping program at the age-group level. Most local road races and non-sanctioned events have no drug testing. The rules are straightforward: GLP-1 is currently permitted everywhere.

Is using GLP-1 to reach race weight cheating?

This is a values question, not a regulatory one. GLP-1 is a legal, prescribed medication. Endurance sport also allows caffeine, altitude training, carbon super shoes, and professional coaching — all conferring measurable advantages. The line between "treatment" and "enhancement" is blurry when weight loss simultaneously treats obesity and improves race performance. My position: follow the rules, be transparent, train hard, and let your results speak for themselves.

Should I tell my coach?

Yes. Your coach needs to know because GLP-1 directly affects fueling strategy, recovery timelines, body composition changes, and training tolerances — all things a coach manages. A coach who does not know you are on GLP-1 cannot properly adjust your nutrition plan or race-day strategy. This is about effective coaching, not about ethics. Your medical decisions are private, but your coach is part of your performance team and needs accurate information to do their job.

Frequently Asked Questions

What is GLP-1 and how does it work for weight loss?

GLP-1 (glucagon-like peptide-1) receptor agonists are injectable medications that mimic a natural gut hormone. They reduce appetite by acting on brain receptors that control hunger and satiety, slow gastric emptying so you feel full longer, and improve insulin sensitivity. The two most common are semaglutide (Ozempic/Wegovy) and tirzepatide (Mounjaro/Zepbound). They were originally developed for type 2 diabetes but are now widely prescribed for weight management.

Who prescribes GLP-1 for athletes?

Any licensed physician can prescribe GLP-1 medications. In practice, endocrinologists, sports medicine doctors, and obesity medicine specialists have the most experience with these drugs. Some athletes use telehealth weight-loss clinics, but I recommend working with a physician who understands endurance training demands. You need someone who will consider your fueling needs, not just your BMI.

How much does GLP-1 cost per month?

Brand-name semaglutide (Wegovy) costs $1,300-1,400/month without insurance. Tirzepatide (Zepbound) runs $1,000-1,100/month. Many insurance plans now cover them with a BMI qualification. Compounded semaglutide from specialty pharmacies costs $200-400/month and is legal in most jurisdictions. Some athletes on lower microdoses spend even less because the supply lasts longer.

Is GLP-1 safe for endurance athletes?

GLP-1 medications have robust safety data from clinical trials involving tens of thousands of patients. The primary concerns for athletes are not unique safety risks but practical ones: reduced fueling ability, GI distress during exercise, and potential lean mass loss. There is no evidence that GLP-1 causes cardiac, musculoskeletal, or metabolic harm in healthy athletes. Work with your physician and monitor bloodwork regularly.

How quickly will I see results from GLP-1?

Most people notice reduced appetite within the first 1-2 weeks. Measurable weight loss typically begins by week 2-4. On my protocol — tirzepatide (Mounjaro) 2.5mg/week — I went from 94.5kg to approximately 90kg at measurement over a 5-week protocol, with body fat dropping from 13.0% to 11.3%. Total weight loss depends on starting weight, dose, and training load. Athletes targeting 4-5kg of fat loss at a conservative dose can expect to reach their goal within 5-8 weeks.

Can I maintain high training volume on GLP-1?

Yes, but it requires attention to fueling. The main challenge is not a direct effect on training capacity — GLP-1 does not impair cardiovascular or muscular function. The challenge is eating enough to support your training load when your appetite is suppressed. Athletes who proactively plan meals and use liquid calories generally maintain full training volume. The first 2-3 weeks of each dose increase are the hardest.

Does GLP-1 affect VO2max or aerobic capacity?

There is no evidence that GLP-1 directly affects VO2max or aerobic capacity. However, weight loss improves relative VO2max (expressed as ml/kg/min) because the denominator decreases. An athlete who loses 5kg without losing fitness will see a meaningful improvement in relative VO2max, which translates to better running economy and faster race times at the same effort level.

How does GLP-1 affect strength training?

GLP-1 does not directly impair strength or muscle contractile function. The concern is indirect: caloric deficit combined with appetite suppression can lead to inadequate protein intake, which accelerates lean mass loss. Athletes who maintain resistance training 2-3x/week and consume 1.8-2.4g protein per kg body weight can largely preserve strength. Some athletes report reduced motivation to eat post-workout, which requires conscious effort to override.

When should I time my GLP-1 injection relative to training?

Inject on your rest day or easy day. Both semaglutide and tirzepatide are weekly injections. I inject tirzepatide (Mounjaro) on Friday evenings, which keeps the peak side effect window clear of my weekend long sessions. Evening injection timing also helped eliminate first-dose nausea — I sleep through the peak GI window. Pick a consistent day and time that works around your hardest training sessions.

Will GLP-1 cause low energy during training?

Some athletes report lower energy in the first 2-4 weeks, primarily because they are eating less due to appetite suppression. This is not a pharmacological effect on energy systems — it is simply under-fueling. The solution is proactive fueling: eat on a schedule rather than relying on hunger cues, prioritize pre-workout meals even if you are not hungry, and use liquid calories if solid food feels unappealing. Most athletes adapt within a month.

Should I stop GLP-1 before a race?

This depends on the race distance and your tolerance. For races under 90 minutes (10K, half marathon), most athletes continue their normal protocol because fueling demands are lower. For marathons and Ironman events, some athletes skip or reduce their dose 1-2 weeks before the race to ensure normal gastric emptying for race-day nutrition. Discuss this with your physician — abruptly stopping can cause rebound appetite and GI changes.

How does GLP-1 change race day fueling?

GLP-1 slows gastric emptying, meaning gels and carbohydrate drinks take longer to absorb. Practical adaptations include: starting fueling earlier, favoring liquid over solid calories, and using smaller, more frequent doses of carbohydrate. That said, impact varies by medication and dose. On tirzepatide 2.5mg, I have had no issues absorbing 100+ grams of carbs per hour during long bike sessions. Test your exact race nutrition protocol in training before assuming you need to reduce intake.

Can I run a marathon on GLP-1?

Absolutely. The keys are: test your race nutrition extensively during long training runs, start fueling early, and have a backup plan if your stomach rebels. The improved power-to-weight ratio from weight loss often more than compensates for any fueling complexity. On GLP-1 (whether that is semaglutide/Ozempic or tirzepatide/Mounjaro), the same fundamentals apply — practice your exact race nutrition protocol in training before race day.

What about triathlon and Ironman on GLP-1?

Triathlon adds complexity because you are fueling across three disciplines over many hours. The bike leg is the primary fueling window, and GI issues from GLP-1 can be worse on the bike due to position and vibration. Many triathletes time their injection 4-5 days before race day, use liquid nutrition exclusively on the bike, and switch to gels only on the run when absorption improves. Practice your exact race nutrition protocol in at least 3-4 long training sessions.

Does GLP-1 affect HYROX performance?

HYROX races last 60-90 minutes for competitive athletes, which means fueling demands are moderate. Most athletes on GLP-1 can complete HYROX with minimal fueling adjustments — a pre-race meal 2-3 hours before and one gel mid-race is typically sufficient. The weight loss benefits for HYROX are significant because the event includes running, sled push, sled pull, and wall balls — all movements where lower body weight is advantageous.

How much muscle will I lose on GLP-1?

Without intervention, clinical data shows 25-40% of weight lost on GLP-1 can be lean mass. The medication matters: tirzepatide (Mounjaro) shows approximately 75% fat / 25% lean mass loss, versus semaglutide (Ozempic/Wegovy) at roughly 60% fat / 40% lean mass. With resistance training 2-3x/week and protein at 1.8-2.4g/kg, athletes can do even better. My circumference data on tirzepatide shows stable thigh and hip measurements while losing trunk fat — consistent with the clinical ratios.

How much protein do I need on GLP-1?

More than you think. I target 140-190g of protein per day (roughly 1.6-2.1g/kg at my current weight), prioritizing protein at every meal. This is challenging with suppressed appetite, so protein shakes and high-protein snacks become essential tools. Spreading intake across 4-5 meals rather than concentrating it in 1-2 large meals improves absorption and reduces GI stress. On GLP-1 (whether semaglutide/Ozempic or tirzepatide/Mounjaro), protein is the single most important macronutrient to protect.

Should I get DEXA scans while on GLP-1?

DEXA is the gold standard for tracking body composition and costs $50-150 per scan. If accessible, get a baseline before starting GLP-1 and scan every 8-12 weeks. I do not use DEXA — I track circumference measurements (waist, belly, hips, thighs, arms) weekly alongside body fat estimates and power output data. This combination tells me where the loss is happening. If your thigh and arm measurements are dropping alongside your waist, you are likely losing lean mass. If limb measurements hold while trunk measurements decrease, you are on track.

What is the optimal body fat percentage for racing?

General targets for competitive age-group endurance athletes are 8-15% for men and 16-23% for women. I went from 13.0% to 11.3% over my GLP-1 protocol, which put me in a good range for Ironman-distance racing without going dangerously low. Going below 8% can impair immune function, hormone production, and recovery. GLP-1 can help you reach the lower end of a healthy range, but it should not be used to push into unsustainable territory. Track your data and work with your physician.

How fast should I expect to lose weight on GLP-1?

For athletes, slower is better. A rate of 0.5-1% of body weight per week preserves more lean mass than rapid loss. For an 85kg athlete, that is 0.4-0.85kg per week. Clinical trial averages show 5-7% body weight lost at 3 months and 12-17% at 12-15 months on full doses. Athletes on lower doses or microdoses will lose less but often preserve more muscle. Patience is a feature, not a bug.

What are the worst side effects of GLP-1 for athletes?

The most commonly reported side effects for athletes are nausea (can prevent fueling during training), reduced appetite (makes hitting calorie and protein targets difficult), and delayed gastric emptying (alters race nutrition absorption). My experience on tirzepatide (Mounjaro) 2.5mg was minimal: first-injection nausea only, which resolved completely after I switched to evening injections on Fridays. Side effect severity varies significantly by medication, dose, and individual. GI symptoms typically resolve within 4-8 weeks at a stable dose.

Can GLP-1 cause nausea during exercise?

Yes, particularly during the first 2-4 weeks and during high-intensity exercise. Exercising with food in your stomach is more likely to cause nausea because GLP-1 slows gastric emptying. Strategies that help: wait 2-3 hours after eating before intense sessions, use liquid rather than solid pre-workout nutrition, reduce intensity during the initial adjustment period, and time injections away from hard training days.

How long do GLP-1 side effects last?

Most GI side effects peak 24-72 hours after each injection and are most intense during the first 4-8 weeks of treatment or after each dose increase. By month 2-3 at a stable dose, most athletes report significant improvement. A small percentage (5-10%) experience persistent nausea that does not resolve, which usually means the dose is too high. If side effects are intolerable after 6-8 weeks, discuss a dose reduction with your physician.

How can I manage GI issues while training on GLP-1?

Practical strategies: eat smaller, more frequent meals instead of large ones. Favor liquid calories when solid food is unappealing. Avoid high-fat and high-fiber foods before training (they slow gastric emptying further). Inject on rest or easy days. Keep a food-symptom diary to identify trigger foods. Use ginger or peppermint for mild nausea. If GI issues persist beyond 6-8 weeks, discuss dose adjustment with your physician.

Can I drink alcohol on GLP-1?

Technically yes, but most athletes find alcohol tolerance is significantly reduced on GLP-1. Many report feeling intoxicated faster and experiencing worse hangovers. GLP-1 slows alcohol absorption, which can lead to unpredictable blood alcohol levels. From a training perspective, alcohol impairs recovery and sleep quality. Most competitive athletes on GLP-1 significantly reduce or eliminate alcohol — the combination of reduced tolerance and training demands makes it impractical.

Is GLP-1 banned by WADA?

No. As of 2026, GLP-1 receptor agonists (semaglutide, tirzepatide) are on WADA's Monitoring Program but NOT on the Prohibited List. This means they are legal for use in and out of competition in all WADA-signatory sports. No Therapeutic Use Exemption is required. WADA is collecting data on prevalence and could move them to the banned list in future years, but there is no indication this is imminent.

Would GLP-1 be detected in a drug test?

Standard anti-doping panels do not currently test for GLP-1 receptor agonists because they are not prohibited substances. If WADA were to ban them, validated detection methods would need to be developed. Semaglutide has a half-life of approximately 7 days and would likely be detectable in blood for several weeks after the last injection. For now, there is no testing and no detection risk because there is nothing to detect against.

What are the rules for age-group competition?

Age-group athletes in WADA-signatory sports (World Athletics, World Triathlon, UCI) follow the same prohibited list as professionals. Since GLP-1 is not on the prohibited list, it is fully legal at all competition levels. HYROX does not have an anti-doping program at the age-group level. Most local running events and non-sanctioned races have no drug testing whatsoever. The rules are clear: GLP-1 is permitted.

Is using GLP-1 to reach race weight considered cheating?

This is an ethical question without a clear answer. GLP-1 is a legal, prescribed medication used under medical supervision. Many endurance athletes also use caffeine, altitude tents, carbon-plated shoes, and expensive coaching — all legal advantages. The distinction between "medical treatment" and "performance enhancement" is blurry when the medical treatment produces a performance benefit. My view: follow the rules, be transparent, and let others draw their own conclusions.

Should I tell my coach that I am using GLP-1?

Yes. Your coach needs to know because GLP-1 affects fueling, recovery, and body composition — all of which impact training prescription. A coach who does not know you are on GLP-1 cannot properly adjust your nutrition plan, manage your weight loss rate, or modify race-day fueling strategy. This is not about ethics — it is about giving your coach the information they need to coach you effectively. Medical privacy is important, but your coach is part of your performance team.