THE SCIENCE

What Happens to Your Muscles on GLP-1 Medications

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GLP-1 receptor agonists like semaglutide and tirzepatide work primarily by suppressing appetite. They are extraordinarily effective at it. Most patients experience a dramatic reduction in hunger, food noise, and caloric intake — often without consciously trying to "diet."

 

This is a strength. But it also introduces a risk that must be actively managed.

 

The muscle loss problem on GLP-1 therapy:

 

When the body is in a significant caloric deficit — which is common on GLP-1 medications — it draws on stored energy to meet its needs. In an ideal scenario, that energy comes entirely from stored fat. In practice, without the stimulus of resistance exercise, the body also breaks down lean muscle tissue for fuel. This process is called muscle protein catabolism.

 

Research on GLP-1 medications and body composition has raised important questions about the proportion of weight lost that comes from muscle vs. fat. A 2023 analysis of the STEP trials found that, on average, approximately 25–39% of total weight lost on semaglutide came from lean body mass — including muscle. At higher doses and greater rates of weight loss, this proportion can be even more significant.

 

For tirzepatide, the SURMOUNT trials showed similar patterns, with lean mass loss contributing to a portion of total weight reduction — though tirzepatide's dual GIP mechanism may offer some favorable effects on fat tissue metabolism specifically.

 

The clinical implications are real:

 

• Muscle loss lowers resting metabolic rate — every pound of muscle you lose reduces the number of calories your body burns at rest. This makes weight maintenance after treatment significantly harder.

• Loss of muscle leads to loss of strength and function — particularly relevant for older adults, where muscle mass is directly tied to independence, fall prevention, and quality of life.

• The "skinny fat" outcome — patients who lose large amounts of weight without resistance training often end up with a lower scale number but a higher body fat percentage relative to their lean mass. This is not a healthy metabolic outcome.

• Rebound risk — a reduced muscle mass means a reduced metabolic foundation. When patients eventually reduce or stop GLP-1 medication, a lower metabolic rate makes weight regain more likely and harder to reverse.

 

Strength training is the intervention that changes this equation entirely.

 

 

 

HOW RESISTANCE TRAINING PROTECTS YOUR RESULTS

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The Science of Strength Training During GLP-1 Therapy

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Resistance training — also called strength training or weight training — provides a direct anabolic (muscle-building) stimulus that counteracts the muscle protein catabolism promoted by caloric deficit.

 

When you engage in resistance exercise, your muscles are exposed to mechanical stress that signals the body to maintain and build muscle tissue. Combined with adequate protein intake, this signal is strong enough to shift the balance of weight loss away from muscle and toward fat — even in the context of GLP-1-mediated caloric restriction.

 

What the research shows:

 

A landmark 2024 study published in Obesity examined the effect of resistance training combined with GLP-1 receptor agonist therapy. Participants who added structured resistance training to their GLP-1 program lost significantly more fat mass and retained significantly more lean muscle compared to those who used medication alone. Their resting metabolic rates also declined less — meaning their bodies remained more metabolically efficient throughout the weight loss period.

 

Additional research from the broader field of dietary caloric restriction consistently demonstrates that resistance exercise is the most effective strategy for preserving lean mass during weight loss — more effective than aerobic exercise, dietary protein alone, or any supplement currently available.

 

Key benefits of resistance training on GLP-1 therapy:

 

• Muscle preservation — resistance training is the most evidence-supported tool for preventing lean mass loss during caloric restriction driven by GLP-1 medications

• Greater fat loss — by preserving metabolically active muscle tissue, patients who strength train lose proportionally more fat for every pound of total weight lost

• Metabolic protection — maintaining muscle prevents the drop in resting metabolic rate that makes weight regain so common after stopping GLP-1 medications

• Improved insulin sensitivity — resistance training independently improves insulin sensitivity through muscle glucose uptake, complementing the metabolic effects of GLP-1/GIP therapy

• Bone density protection — weight-bearing exercise is one of the most effective interventions for maintaining or improving bone density, which is particularly important for women in perimenopause or menopause

• Physical strength and function — patients who strength train during their GLP-1 program end their program not just lighter, but functionally stronger

• Body composition aesthetics — muscle gives the body shape, tone, and structure. Patients who strength train alongside GLP-1 therapy consistently report more satisfaction with how their body looks at the same scale weight compared to those who do not

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BENEFITS OF STRENGTH TRAINING ON GLP-1 MEDICATIONS

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Benefits of Adding Resistance Exercise to Your Weight Loss Program

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Combining GLP-1 therapy with consistent resistance training is not optional for optimal outcomes — it is the clinical standard of care. Here is what that combination delivers:

 

• Significantly greater reduction in body fat percentage compared to GLP-1 therapy alone

• Preservation of lean muscle mass — confirmed through DEXA body composition scanning included in Monaco's membership

• Improved resting metabolic rate, making long-term weight maintenance far more achievable

• Better blood sugar control through an independent mechanism — muscle tissue is a major site of glucose disposal

• Reduced cardiovascular risk through improvements in both weight and physical conditioning

• Stronger bones, reduced fracture risk, and improved posture

• Greater daily energy and reduced fatigue — muscle tissue is more metabolically efficient than fat tissue

• Improved mental health outcomes — resistance training has strong, independent evidence for reducing anxiety, depression, and improving overall mood and cognitive function

• Confidence that grows not just from the number on the scale, but from what your body can do

 

 

 

OUR GYM PARTNERSHIPS IN BAKERSFIELD

Local Fitness Access — Built Into Your Monaco Membership

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Monaco Aesthetics & Wellness has established partnerships with local Bakersfield fitness facilities to give Weight Loss Wellness Program members access to quality training environments at a special membership rate. Whether you prefer a traditional strength and conditioning gym, a group fitness format, or something in between, our goal is to match you with a local option that fits your training style and schedule.

 

Our gym partnerships are designed to evolve alongside our program — we continue to expand our network of local fitness partners to ensure every Monaco member has a convenient, affordable option for the resistance training that makes GLP-1 therapy work at its highest potential.

 

What to look for in a gym while on GLP-1 therapy:

 

• Access to free weights, resistance machines, or cable equipment for progressive overload training — the most important modality for muscle preservation

• A welcoming environment for all fitness levels, including beginners

• Coaching or instructional support, whether through staff, personal training, or structured group classes

• Consistency — the best gym is the one you'll actually go to

 

As a Monaco Weight Loss Wellness Program member, you'll receive special pricing at our partner gyms in Bakersfield — details provided at your program onboarding. Ask our team at your consultation about current gym partners and which option may be the best fit for you.

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WHO IS A GOOD CANDIDATE?

Who Should Prioritize Strength Training During GLP-1 Therapy?

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The honest answer: every patient on GLP-1 medications should incorporate some form of resistance training. But it is especially critical for:

 

• All GLP-1 patients — muscle loss during caloric restriction is a universal risk that applies regardless of which medication you're taking or how much weight you're losing

• Patients with significant weight loss goals — the larger the caloric deficit and the more weight you plan to lose, the more important resistance exercise becomes for preserving lean mass

• Women in perimenopause or menopause — hormonal changes during this life stage accelerate both muscle loss (sarcopenia) and bone density decline; resistance training counteracts both simultaneously

• Adults over 40 — sarcopenia (age-related muscle loss) begins as early as the mid-30s and accelerates with age; strength training is the primary intervention

• Patients with insulin resistance or pre-diabetes — muscle tissue is a major site of glucose uptake; building and maintaining muscle directly improves insulin sensitivity

• Patients concerned about aesthetics — those who want their weight loss to translate into a toned, strong physique rather than simply a smaller version of the same body composition

 

If you're unsure where to start, your Monaco coaching session is the right place to begin that conversation.

 

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WHAT TO EXPECT

Getting Started with Strength Training as a Monaco Program Member

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Starting Where You Are You do not need to be fit to begin strength training. Our local gyms that we hand picked accommodate all fitness levels — from patients who have never lifted weights to those returning to training after a long break. What matters is that you start, and that you progress consistently over time.

 

How Much Training Is Needed? Research suggests that 2–3 resistance training sessions per week is sufficient to produce meaningful muscle preservation and growth during GLP-1 therapy. Sessions do not need to be long — 30 to 45 minutes of focused resistance training, two to three times per week, is a clinically meaningful dose.

 

Protein: The Non-Negotiable Partner to Resistance Training Exercise provides the stimulus for muscle preservation. Protein provides the building blocks. During GLP-1 therapy, prioritizing adequate daily protein intake — typically 0.7–1.0 grams per pound of body weight — is essential for the muscle preservation benefits of resistance training to be fully realized. Monaco's supplement discount (20% off, included in your membership) makes meeting your protein targets more affordable throughout your program.

 

Tracking Your Progress with DEXA The only way to know for certain whether your strength training is protecting your muscle mass is through objective body composition measurement. Your two included DEXA scans — performed through Monaco's partnership with Body Fat Clinic in Bakersfield — give you exactly this data: a before and after comparison of your lean muscle mass, fat mass, and body fat percentage. This is the data that tells you your training is working — even when the scale isn't moving the way you expected.

 

What to Expect in the First Few Weeks New exercisers often experience initial soreness (delayed onset muscle soreness, or DOMS), particularly in the first one to two weeks. This is a normal, temporary response to new muscular stress and diminishes rapidly as the body adapts. Energy levels during this phase are also influenced by GLP-1-related caloric reduction — which is another reason starting at a manageable training volume and progressing gradually is the right approach.

 

 

 

RESULTS

What Happens When You Combine GLP-1 Therapy with Strength Training

The combination of GLP-1 medication and resistance training produces a body composition outcome that neither approach can achieve alone.

 

GLP-1 therapy creates the caloric deficit that drives fat loss at a rate that diet alone cannot sustain. Resistance training ensures that the weight being lost is fat — not muscle. DEXA scanning confirms this is happening. Protein and supplement support provides the nutritional foundation. Coaching keeps you accountable through the inevitable plateaus and difficult weeks.

 

Patients who commit to all of these components — medication, movement, nutrition, tracking, and support — consistently achieve the strongest results: meaningful reductions in fat mass, preserved or improved lean muscle, better metabolic health markers, and a body that not only weighs less but functions, feels, and looks genuinely different.

 

This is the Monaco program working at its highest potential. And it starts with understanding that the gym isn't optional — it's part of the medicine.

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WHY CHOOSE MONACO

Why Monaco's Integrated Approach to GLP-1 Therapy and Fitness Sets Us Apart

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Most medical weight loss programs prescribe medication and send patients home. Monaco's Weight Loss Wellness Program is built differently — because we know the evidence, and we know that medication alone is not the whole answer.

 

• Fitness access built into the membership — special pricing at our network of local Bakersfield gym partners removes the cost barrier between you and the resistance training your body needs

• DEXA scanning to confirm muscle preservation — not guessing; measuring. Your body composition data is part of your clinical record.

• Protein and supplement support — 20% off vitamins and supplements to help you meet the nutritional demands of active weight loss

• Coaching integration — your complimentary coaching session is the ideal place to build a movement plan that fits your starting point and lifestyle

• Medical oversight throughout — your GLP-1 dosing, nutrition recommendations, and program adjustments are informed by your body composition data and your activity level

• A philosophy rooted in long-term results — we measure success not just by how much weight you lose, but by what your body is made of when you're done losing it

 

Monaco Aesthetics & Wellness is located at 9510 Flushing Quail Rd, Suite 122 in Bakersfield, CA — and we've partnered with Bakersfield's best fitness facilities to make sure every patient in our program has the support they need to succeed completely.

 

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Strength Training + GLP-1 Therapy FAQ

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Do I really need to exercise if the medication is already helping me lose weight?

Yes — and the reason is body composition, not just weight. GLP-1 medications are highly effective at reducing caloric intake and promoting weight loss, but without resistance training, a significant portion of that weight can come from lean muscle mass. Losing muscle reduces your metabolic rate and increases the risk of weight regain after treatment ends. Resistance training is the most evidence-backed strategy for preventing this — and it's why Monaco has made gym access a component of every membership.

 

What kind of exercise is most important on GLP-1 therapy?

Resistance training — also called strength training or weight training — is the most important modality for muscle preservation during GLP-1-mediated weight loss.

Cardiovascular exercise (walking, cycling, aerobic training) supports heart health and caloric expenditure, but it does not provide the mechanical stimulus needed to maintain lean muscle mass. Ideally, patients incorporate both — but if you can only do one, prioritize resistance training.

 

How much protein do I need while on semaglutide or tirzepatide?

Most clinical guidelines for patients in active weight loss recommend 0.7 to 1.0 grams of protein per pound of body weight daily. Because GLP-1 medications reduce overall appetite and food intake, hitting this target requires intentional planning. Prioritizing protein at every meal, using protein supplements when needed, and using the Monaco member 20% supplement discount are all strategies our team will help you with.

 

I've never lifted weights before. Where do I start?

Our gym partners accommodate all fitness levels, including complete beginners. Some patients do best in a structured group fitness environment where coaching and community make showing up easier. Others prefer a traditional gym where they can learn at their own pace. Your Monaco coaching session is a great starting point for identifying which environment fits your personality and schedule — and our team can point you toward the right local partner for your needs.

 

Will I lose muscle even if I exercise?

With consistent resistance training and adequate protein intake, the goal is to minimize or eliminate net lean mass loss during GLP-1 therapy. Research confirms that patients who strength train during GLP-1-mediated weight loss retain significantly more lean mass than those who do not. Complete preservation of all lean mass during an aggressive weight loss phase is not always achievable, but the difference between training and not training is clinically significant — and measurable on DEXA.

 

Can strength training make me gain weight while I'm trying to lose it?

It's a common concern, and the answer is nuanced. Resistance training can cause initial water retention in muscles as they adapt, and muscle tissue is denser than fat — meaning it weighs more per volume. However, resistance training does not typically cause overall weight gain in a patient on GLP-1 therapy, because the caloric restriction created by the medication far outweighs any minor weight fluctuation from training adaptation. More importantly, DEXA scanning reveals what the scale cannot: if your fat is decreasing and your muscle is being maintained or growing, your program is succeeding — regardless of what the scale says on a given week.

 

How do I get the special gym membership pricing?

As a Monaco Weight Loss Wellness Program member, your special pricing at our partner gyms in Bakersfield is part of your membership. Details on current gym partners and how to access your discount will be provided at your consultation or program onboarding. Our network of gym partners continues to grow — ask our team for the most up-to-date list.

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Lose the Fat. Keep the Muscle. Build Something That Lasts.

GLP-1 therapy changes the equation for weight loss. Strength training changes what that weight loss is made of. Together, they deliver results that are not just impressive on a scale — but real, lasting, and functional.

 

Monaco's Weight Loss Wellness Program in Bakersfield, CA gives you both — medically supervised GLP-1 therapy, DEXA body composition tracking, and built-in access to the gym time that makes your results stick.