GLP-1 side effect management: prevent muscle loss and MSK costs

GLP-1 medications have transformed the landscape of obesity care. For benefits leaders and health plans, they offer a rare promise: a clinically proven intervention that can deliver meaningful weight loss across at-risk populations.

But that weight loss comes at a hidden cost — one that doesn’t show up on the prescription data, but does show up in your MSK claims.

That cost is lost lean muscle mass.

Muscle is essential for metabolism, movement, and protection against injury. Yet up to 39% of lean body mass is lost during GLP-1 usage. That lean mass loss increases pain, fall risk, and disability rates — driving a quiet second wave of claims that erode the ROI of GLP-1 investments.

Before analyzing how to prevent lean muscle loss in detail, let’s first cover the range of potential side effects of GLP-1 medication

What are the side effects of GLP-1s?

GLP-1 receptor agonists, including semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound), are commonly prescribed for weight loss. Their most well-known side effects include:

• Nausea, vomiting, diarrhea, constipation
• Appetite suppression leading to low nutrient intake
• Headaches, fatigue, dizziness
• Gallbladder issues, pancreatitis (in rare cases)
• Injection site reactions

These effects often show up early in treatment and may fade over time. But that one hidden side effect grows more severe the longer it goes unaddressed: loss of lean muscle mass.

How soon do GLP-1 side effects start?

• Gastrointestinal issues tend to appear within hours or days
• Appetite suppression leads to caloric restriction and fatigue within weeks
• Muscle loss builds silently, especially in sedentary members

Muscle loss doesn’t trigger a pharmacy flag or a diagnostic code, so it often goes unnoticed. The impact shows up later in the form of back pain, falls, joint instability, or disability claims. This can lead to costly downstream musculoskeletal care and even surgical intervention.

Lean muscle loss is the GLP-1 side effect you can’t afford to ignore

Weight may drop. But prescribing GLP-1 medication without movement support leaves a patient at high risk of lost lean muscle mass. 

These effects don’t appear on pharmacy claims. But they’re showing up in rising musculoskeletal (MSK) costs across GLP-1 populations.

To manage GLP-1 side effects effectively, health plans and employers need a clear strategy to preserve lean muscle mass — and structured movement is the foundation.

Lean muscle retention is the best defense against MSK risk

When members lose weight through appetite suppression alone, the body sheds both fat and muscle. Without strength-building movement, GLP-1 users risk losing high proportions of lean muscle mass. 

But muscle isn’t excess — it’s essential.

Benefits of lean muscle mass

• Protects the joints and spine by absorbing impact and stabilizing movement
• Reduces fall risk by supporting balance and coordination
• Injury prevention through balance and joint stabilization
• Fuel metabolisms by burning energy even at rest
• Prevents functional decline and supports everyday activities

During GLP-1-induced weight loss, Up to 39% of lean body mass is lost during GLP-1 usage, especially in inactive users. Losing this tissue slows metabolism, which means fat returns more quickly if the member discontinues the medication.

That muscle isn’t easy to regain and the results are dangerous for patients and insurers alike:

• Metabolism slows → weight rebound risk increases
• Fall risk increases → MSK claims rise
• Strength drops → long-term care exposure grows
• Functional impairments → long-term disability risk

This isn’t hypothetical. Sarcopenia (progressive loss of muscle tissue) doesn’t often show up as a line item on a claim. But its consequences do. These effects are well-documented in clinical literature:

• Sarcopenia contributes to 33% of chronic pain in older adults
• It increases fall risk by 60%
• In people with sarcopenic obesity (low muscle, high fat), disability risk jumps 2.5x

GLP-1s accelerate sarcopenia without a plan to prevent muscle loss, employers are setting themselves up for a second wave of downstream claims and costs.

Sarcopenia adds nearly $900 in excess healthcare costs per member per year.

GLP-1 medications accelerate muscle loss

This is especially true in inactive users

This muscle loss side effect is amplified when members are already physically inactive. And for most, that’s the case:

• Only 1 in 4 U.S. adults meet CDC activity guidelines for aerobic and muscle-strengthening movement
• Within the Sword Move population:

Muscle loss is such a dangerous side effect of GLP-1s, but it’s also one of the most preventable.

The solution is straightforward.

Structured movement plans should be built into all GLP-1 treatment programs to encourage positive behaviour change, develop physical activity habits, and prevent muscle loss.

Movement is great medicine for managing GLP-1 side effects

GLP-1s suppress appetite, but they don’t help patients retain muscle when weight is lost.

Without structured movement plans or regular physical activity to support weight loss, patients become metabolically unhealthy and put themselves at risk of injury. Movement isn’t just a helpful adjunct to medication. For GLP-1 users, physical activity is a clinical protection mechanism.

Structured physical activity:

• Preserves lean muscle mass to support metabolism
• Reduces fall and injury risk by strengthening stabilizing muscles
• Builds habits that help members transition successfully after discontinuing medication

Healthcare providers can proactively embed movement into a GLP-1 weight loss care model to prevent the dangerous side effect of lean muscle loss — before it becomes a downstream cost driver.

Add Move to GLP-1 treatment for sustainable weight loss

Sword Move solves the GLP-1 muscle loss problem at scale.

Move’s digitally delivered physical therapy program allows patients to complete their exercises at a time and place that suits their life. 

What does Move provide for GLP-1 patients?

• Personalized strength-building movement plans
• Expert clinical support and supervision
• Real-time tracking via wearable sensors or smart devices
• Ongoing adjustments based on progress, capacity, and risk

What improvements does Move deliver?

• 69% of previously inactive and insufficiently active members become “active or healthy active” in 10 weeks
• 4.5 sessions/week completed on average
• Sedentary time for previously inactive and insufficiently active members reduced by 1 hour 22 minutes/day
• 74% report feeling moderately or much better

These changes directly counteract the downstream risks of GLP-1 muscle loss.

Move helps members build strength, retain muscle, and increase resilience, while allowing employers to track outcomes, reduce MSK claims, and protect GLP-1 ROI.

GLP-1 preauthorization of movement plans: drive sustainable weight loss

Many providers use Move as a preauthorization mechanism for a period of 8-10 weeks to help their members develop regular physical activity habits. 

With that support, some members can:

• Build enough metabolic and physical progress to delay or skip GLP-1 medication altogether
• Better prepare for the demands of therapy
• Develop foundational movement habits to retain muscle and support long-term health

This is the core value of preauthorized movement plans: they screen for readiness, create behavior change, and protect against the significant risk of downstream musculoskeletal conditions and costly medical interventions.

The smarter GLP-1 side effect management strategy

Effective GLP-1 benefit design requires a prevention-first approach. Here’s what leading plans are implementing now to protect spend, improve healthcare outcomes, and optimize ROI:

1. Audit MSK and fall-related claims

Look 6 to 12 months post-GLP-1 initiation to identify pain, physical therapy, and fall-related ER visits.

2. Flag at-risk members

Watch for signs of rapid weight loss with low activity, poor refill adherence, and new MSK complaints.

3. Require structured movement alongside medication

Prescribing GLP-1s without movement is like cutting calories without nutrients. The plan is incomplete and the longer-term results can be damaging and costly.

4. Choose vendors who track real outcomes

Work with partners who provide reporting on:

• Activity level improvement
• Functional change
• Sedentary time
• Member-reported well-being

Only then can you turn side effect management from a cost center into a measurable ROI engine.

Sword Move: the movement multiplier your GLP-1 program needs

GLP-1s suppress appetite, but they aren’t designed to retain muscle mass. 

Movement protects against the common risk of lean muscle loss, helping patients to retain and build strength. 

Sword’s Move closes the clinical gap left by GLP-1s, giving members structured movement programs to retain strength and lean muscle mass. Move is the ideal support to a GLP-1 prescription as patients will build new physcial activity habits to protect long term health outcomes.

Employers and health insurers alike can maximize GLP-1 investment with speed and scale by combining Move with all GLP-1 prescriptions. 

FAQ: Managing the side effects of GLP-1 medications

Is muscle loss really that common on GLP-1s? Yes. Clinical data shows up to 39% of lean body mass is lost during GLP-1 usage, particularly in inactive individuals.

Can structured movement really offset the risk? Yes. Clinical and real-world data support movement as a lean mass preservation strategy. It also builds daily behavior change that protects long-term outcomes.