Protecting Muscle and Bone on GLP-1 Medications

As part of our ongoing GLP-1 series at Legacy Community Health, we’re committed to supporting every patient’s whole health. GLP-1 medications are increasingly used to manage blood sugar and assist with weight loss, but they come with less obvious risks, particularly to muscle and bone health.

Understanding these risks is key to protecting your strength and long-term well-being while benefiting from your treatment.

The Hidden Consequences of Rapid Weight Loss

GLP-1 medications do a great job helping many people lose weight and manage Type 2 diabetes. But losing weight quickly can sometimes cause side effects you might not expect, like missing out on important nutrients such as protein, calcium, and vitamin D, changes in hormones that keep your bones strong, and even bone loss that happens faster than your body can rebuild.

These changes can reduce bone density and increase fracture risk, especially in women over 40 and older adults.

Who Should Use GLP-1 Medications?

Clinical guidelines recommend GLP-1s for individuals who:

• Have Type 2 diabetes needing blood sugar control
• Have a BMI over 30
• Have a BMI between 27–29.9 with weight-related health issues such as high blood pressure

Some people use GLP-1s primarily for weight loss without full awareness of potential side effects, which may lead to unintended health issues.

Why Muscle and Bone Matter

When people lose weight quickly, they often lose muscle along with fat, weakening the body’s foundation. Muscle supports metabolism, strength, and bone stability.

“GLP-1 inhibitors reduce appetite, so patients eat less and lose weight, but it’s not just fat that’s lost,” says Sean Barrett, RD, of Legacy Community Health. “Up to 40% of weight lost can be lean body mass, which includes muscle, bone, water, and skin. Lean mass is metabolically active. It helps burn calories even at rest. More muscle lowers the risk of chronic conditions like diabetes and heart disease.”

Muscle tissue also supports vital organs such as the heart, bladder, intestines, and blood vessels.

Strong bones are essential to staying active and healthy, yet their loss often goes unnoticed. Research shows that even if you eat enough protein, cutting calories too much can still harm your bone health, though protein does help protect your muscles.

“A low-calorie and high-protein diet accentuates the detrimental impact that calorie restriction has on bone,” Barrett adds. A high-protein diet is beneficial for muscle mass. However, significant bone deterioration can happen.

What Can We Do About It?

Protecting muscle and bone health while on GLP-1 medications requires a balanced approach:

• Stay Active. Weight-bearing and resistance exercises like walking, jogging, and strength training are crucial to preserving muscle and strengthening bones, especially during weight loss.
• Eat Smart. A diet rich in protein, calcium, and vitamin D supports muscle maintenance and bone health. Consulting a dietitian can help tailor your nutrition to your needs.
• Keep Track. Start with a baseline bone density scan (DXA) and follow up regularly if you use GLP-1s long term to monitor bone health.

“Adequate protein and regular resistance training are key to reducing muscle and bone loss,” says Barrett. “Calcium, vitamin D, magnesium, and vitamin K2 also play important roles. The encouraging part is that bone loss from rapid weight loss can often be managed or even reversed with proper care.”

Supplements That May Help

To address potential nutrient gaps, consider:

• Vitamin B12 for nerve and blood cell health
• Vitamin D for bone strength and insulin regulation
• Iron for energy and oxygen delivery
• Calcium to maintain bone density
• Omega-3s for heart health and cholesterol balance
• Multivitamins to fill overall nutritional gaps

What This Means for You

GLP-1 medications can be powerful tools for managing diabetes and supporting weight loss, but they’re not a standalone solution. They work best when combined with proper nutrition, physical activity, and regular monitoring.

“GLP-1s are only one part of the weight loss equation,” says Neha Agrawal, Pharm.D., AAHIVP, Director of Clinical Pharmacy Services at Legacy. “Without proper diet and exercise, patients may face complications like osteoporosis or sarcopenia.”

She emphasizes the importance of labs before and during therapy: “Patients on GLP-1s for weight loss should get baseline labs done before starting therapy, and repeat them regularly as recommended by their provider.”

At Legacy, pharmacists are available to counsel patients at retail locations. Clinical Pharmacy Specialists also prescribe GLP-1s in collaboration with providers.

“We offer comprehensive support—monitoring labs, vitals, and side effects—to guide patients through every step of their GLP-1 journey,” Dr. Agrawal says.

Thinking about starting a GLP-1, or already on one? Partner with your Legacy care team to protect not just your weight goals, but your overall health, strength, and mobility.