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Weightlifting on GLP-1 Medications: Ozempic, Wegovy, Mounjaro, Zepbound

January 30, 2026

GLP-1 weight loss medications such as Ozempic, Wegovy, Mounjaro, and Zepbound have become widely discussed and used in Vienna, Austria, and around the world. These medications change the way appetite and eating behaviour work and help many people achieve significant weight loss.

However, weight loss by itself is not always a sign of improved health. Scientific evidence shows that when body weight falls rapidly from energy reduction, a meaningful proportion of that loss can include lean mass rather than fat mass. Lean mass includes muscle tissue, which is essential for strength, metabolism, daily function, and long term health outcomes. People using GLP-1 medications therefore need to understand how to protect lean tissue while pursuing weight loss.

Strength training is the clearest way to preserve lean mass during weight loss. In this article I explain the science behind weight loss with GLP-1 medications, the role of strength training, and provide a simple beginner training structure you can use.

Weight Loss With GLP-1 Medications and Lean Mass

Clinical trials of GLP-1 receptor agonists consistently show measurable changes in body composition. Body composition is commonly assessed using DXA scanning, which distinguishes fat mass from lean mass. Recent peer reviewed research shows that while most of the weight lost with GLP-1 treatment is fat tissue, a sizeable fraction can be lean tissue.

For example, data from trials of semaglutide (the active drug in Ozempic and Wegovy) and tirzepatide (the active drug in Mounjaro and Zepbound) show that weight loss can include lean mass and fat mass simultaneously. In a DXA substudy of the SURMOUNT-1 tirzepatide trial, total body weight dropped by about 21.3 percent, fat mass dropped by 33.9 percent, and lean mass dropped by 10.9 percent. In that study, lean mass loss made up about 26 percent of total weight loss with tirzepatide. Other analyses estimate that lean mass loss can be up to 30 or 40 percent of total weight loss in people using GLP-1 medications. These proportions vary by individual and dose. The consistent point in the scientific literature is that lean mass loss is not negligible.

Why Lean Mass Loss Matters

Loss of lean mass is not just a cosmetic issue. Skeletal muscle plays core roles in strength, mobility, and metabolic function. Having more muscle is linked to better physical performance, better glucose regulation, and lower risk of injury. In older adults, unintentional lean mass loss can lead to lower physical function and increased frailty.

When weight loss includes significant lean mass loss, people can experience lower strength, lower energy, and slower metabolism. This can make it harder to sustain activity and can reduce the daily function that matters most in real life.

GLP-1 medications reduce appetite and eating drive. That is part of how they work. But lower appetite can also make it easier to under-eat protein or calories overall, which increases the risk that the body removes lean tissue during weight loss.

Strength Training Preserves Lean Mass

The scientific evidence about structured resistance training shows that lifting weights sends a clear biological signal to the body that muscle tissue is needed. Resistance training causes mechanical and metabolic stress in muscle tissue that stimulates adaptations such as protein synthesis and cellular signalling that favour retention or growth of muscle.

Although randomized trials specifically testing resistance training plus GLP-1 therapy are still emerging, available evidence supports the general principle that strength training biases weight loss toward fat and away from lean mass. A recent case series published in 2025 showed that people on GLP-1 medications who deliberately combined strength training with higher protein intake were able to preserve or even increase lean mass while losing fat mass.

This evidence is supported by broader research in weight loss and exercise science showing that structured exercise during energy reduction improves functional outcomes and reduces loss of lean tissue compared with dieting alone.

Regulatory Framing: Lifestyle Still Matters

Regulatory authorities such as the European Medicines Agency list GLP-1 medications for weight management as an adjunct to a reduced-calorie diet and increased physical activity. This means that diet and physical activity are expected components of effective use of these medications. In Austria, national public health guidance also recommends at least two days per week of muscle strengthening activity for adults to support overall health, in addition to aerobic activity.

A Simple Beginner Strength Training Template

Below is a straightforward strength training structure that aligns with current activity guidelines and scientific evidence. This is not a prescription. It is a simple template that you can adapt to your skills, equipment, and schedule. The aim is to provide a consistent signal to your muscles during weight loss.

Weekly Structure

Pick one of the following options:

Option A: 2 days per week

  • Full-body strength sessions on two non-consecutive days

Option B: 3 days per week

  • Full-body strength sessions on alternate days

Suggested Movement Categories

In each session, include one exercise from each of the categories below:

  • Squat pattern: examples include goblet squat or split squat
  • Hip hinge pattern: examples include Romanian deadlift or hip hinge with dumbbells
  • Push pattern: examples include machine chest press or dumbbell press
  • Pull pattern: examples include lat pulldown or row
  • Carry or core: examples include farmer carries or anti-rotation core press

Sessions should be short and focused. Your goal is to complete sets that feel challenging without exhausting you for the next session. A practical rule is to choose a resistance where you feel you could perform two to three more repetitions at the end of each set.

How to Track Progress

Because body weight alone does not show what you are gaining or losing, use other indicators to track progress:

  • Strength performance in training sessions
  • Measurements (for example waist circumference)
  • Progress photos over time
  • Daily function such as carrying groceries or climbing stairs

Practical Considerations for People on GLP-1 Medications

If you are taking a GLP-1 medication, appetite suppression and variable energy levels can make training feel harder some days. That is normal. Adjust training timing and session length in ways that fit your energy pattern. Do not let low appetite erase protein intake for the day. Aim to include protein in meals early, when appetite is higher.

Safety Note

This article is a training and science guide, not medical advice. If you have diabetes, use glucose-lowering medications, or have any medical condition that affects exercise tolerance, speak with your clinician before beginning a new training program.

Conclusion

GLP-1 medications such as Ozempic, Wegovy, Mounjaro, and Zepbound help many people reduce body weight. However, a significant portion of weight lost can be lean mass rather than fat mass. Strength training is the clearest way to protect lean tissue while pursuing weight loss.

If you want to lose fat but maintain strength and physical function, strength training should be part of your plan.

For personalised, in-person strength training support in Vienna that helps you start lifting safely and effectively while using a GLP-1 medication, book a free 15 minute intro call.

References

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