National surveys estimate that about one in eight U.S. adults have now taken a GLP-1, whether for diabetes, weight loss or other indications. With the rapid expansion of GLP-1 use among the general population, it’s important that we take a look at how they may be impacting the health and fitness efforts of runners.
At first glance, prescription medications for weight loss or diabetes might seem far removed from the track, treadmill or pavement. However, they’ve quickly become part of many runners’ journeys. Thousands of people who never thought they could achieve their goal weight now have new hope through a method that has shown effective in many. Let’s break down what GLP-1 medications are, how they impact current runners, what new runners should know, and some of the known risks associated.
WHAT ARE GLP-1s (AND WHY THE BUZZ?)
GLP-1 stands for glucagon-like peptide-1, a hormone produced in your small intestine. It helps regulate blood sugar, triggers insulin release, slows digestion and promotes feelings of fullness. Medical researcher John Eng played a key role in the breakthrough to use of these medications when he made a discovery studying the venom of Gila monsters.[1]
GLP-1 receptor agonist medications mimic the glucagon-like peptide-1, giving your body similar metabolic signals. Because of this, they are effective for treating type 2 diabetes and, more recently, obesity.[2] Many people using GLP-1s lose 15–20% of their body weight when paired with lifestyle changes.[3]
As more people experience significant weight loss, interest in expanding exercise routines to include running has grown, so it’s important to understand how GLP-1s affect runners both established and new to the sport.
GLP-1s AND HOW THEY AFFECT PERFORMANCE
If you’re already a runner, GLP-1s may influence your training in several ways. For example:
- Easier impact on joints. If body weight has reduced, running may feel smoother, and joint strain can decrease.
- Better metabolic control. Improved blood sugar regulation may help prevent mid-run crashes and support steadier energy.
- Changes in appetite and fueling. Because GLP-1s reduce hunger and slow digestion, runners may need to plan fueling differently than in the past.
In short, current runners often notice meaningful changes — both positive and challenging — as their bodies adjust.
RISKS AND CONSIDERATIONS FOR ACTIVE RUNNERS
Although GLP-1s offer benefits, runners should watch for potential drawbacks:
- Muscle Loss and Strength Decline
Rapid weight loss often leads to reduced lean muscle mass.[4] Consequently, you may feel weaker or less stable on the run.
What to do:
- Increase protein intake
- Add resistance training 2-3 times a week
- Incorporate cross-training workouts and classes to support muscle maintenance and growth
- Digestive Issues and Fueling Challenges
GLP-1s slow digestion, which may make pre-run meals uncomfortable and cause GI issues during training. Because of this, runners may need to experiment with timing, lighter fueling options or liquid calories.
- Training Adjustments
Side effects like nausea or dizziness may be more noticeable during harder workouts. For runners, it is important to ease into your speedwork and prioritize hydration. In addition, recovery may be slower. If you’re under-fueling (even unintentionally), soreness lingers longer, hard workouts feel harder and back-to-back run days feel rough. Recovery requires adequate calories + protein + carbs — three things GLP-1s often reduce.
- Injury and Bone Stress Risk
Lower body weight + reduced intake can mean lower bone density over time and increased risk of stress fractures, which may be a concern for high-mileage runners or those with a history of RED-S (Relative Energy Deficiency in Sport).
- Performance Issues
Many runners notice slower race times, less pop/speed, and reduced motivation for hard efforts. The trade-off may be worth it if health is the main goal, but can be frustrating if performance matters.
A NEW WAVE OF FIRST-TIME RUNNERS
For some who have lost significant weight, GLP-1 medications are opening doors for people who previously thought running wasn’t possible. Weight, mobility or confidence barriers may have made running feel intimidating. Whereas now, reduced joint strain and improved energy make movement more accessible.
As a result, more women are:
- Starting walk/run intervals.
- Signing up for their first 5K. Learn more about training for your first 5K.
- Joining supportive running groups like Moms on the Run.
- Discovering the emotional and social benefits of being active.
Running becomes not just exercise, but a new expression of identity: “Maybe I really can do this.”
WHAT NEW RUNNERS SHOULD KNOW BEFORE STARTING
If you have the approval of your physician and you’re just beginning your running journey while on a GLP-1, a thoughtful approach increases your chance for success.
- Start Slow (and Celebrate Progress)
Your body is adjusting in multiple ways — including weight changes and metabolic shifts. Therefore, make gradual increases in running time/duration, distance and intensity. Running groups such as Moms on the Run offer running programs tailored to new runners.
- Fueling Still Matters
Even with a reduced appetite, your body needs energy for running. In addition, under-fueling can increase fatigue or injury risk. Learn more about runner nutrition.
- Strength Training Supports Injury Prevention
New runners benefit from building foundational strength — especially during rapid weight loss.
- Expect Some Trial and Error
You may need to adjust run timing, hydration or fueling as your body responds to the medication.
Ultimately, patience and consistency build confidence, capability and joy in running.
FINAL THOUGHTS
GLP-1 medications are having a powerful moment in health and wellness. For the best long-term results (whether you’re a seasoned runner or a brand-new one), it is important to pair medication with movement, strength, nutrition and a supportive community. Supportive running groups, such as Moms on the Run, help many women find this support.
Ultimately, GLP-1s may increase the desire to run, but running itself is what builds endurance, confidence and connection. And with the right coaching and community, every runner can find their stride.
References:
[1] The discovery and development of GLP-1 based drugs that have revolutionized the treatment of obesity | PNAS
[2] GLP-1 Agonists: What They Are, How They Work & Side Effects
[3] GLP-1 and health: Beyond weight loss in the Ozempic era
[4] Rapid weight loss can lead to loss of muscle mass | UCLA Health