Do GLP-1s Cause Muscle Loss? (And How to Prevent It)

This post may contain affiliate links, which means I may earn a small commission at no additional cost to you if you choose to purchase through them. I only recommend products I personally use and trust.

This content is for educational and informational purposes only and does not constitute medical advice. Always consult your healthcare provider before beginning any medication, nutrition, or exercise program.

When I was on the phone with my doctor asking all the questions I could think about starting a GLP-1, my first question was how do I avoid losing muscle. She told me this is one of the first fears women Google after starting a GLP-1:

• Am I losing muscle?
• Is this ruining my metabolism?
• Will I look smaller but softer?
• Will the weight come back worse if I decide to get off of this?

Here’s exactly what she told me: GLP-1 medications do not directly cause muscle loss. But rapid weight loss without adequate protein and resistance training can increase the risk. She made me promise nothing about my diet or exercise routine would change.

Where the Fear of Muscle Loss (and Muscle Gain) Really Comes From

For the past 30 years, women have been conditioned to fear two things at the same time: gaining weight… and gaining muscle. In the 90s and early 2000s, thinness was the goal—cardio-heavy, low-fat, “toning” but never “building.”

When you lose weight, no matter how you do it, your body loses a combination of fat mass, water, and lean mass (which includes muscle). That’s not a GLP-1 issue. It’s biology.

Where GLP-1 enters the conversation is appetite suppression: some women unintentionally eat far less than they realize—especially protein. The risk isn’t the medication itself. It’s not protecting muscle intentionally.

Here are the facts plain and simple:

• Muscle is not bulk.
• Muscle is metabolic protection.
• Muscle is insulin sensitivity.
• Muscle is blood sugar stability.
• Muscle is longevity.
• Muscle is freedom.

Why Muscle Matters So Much

Did you know muscle supports:

• Resting metabolic rate
• Insulin sensitivity
• Blood sugar regulation
• Long-term fat loss maintenance
• Strength and bone density

Especially for women with PCOS and insulin resistance, muscle is protective. Losing muscle while losing fat can slow metabolism over time, which is why strategy matters. This isn’t just about aesthetics. It’s about metabolic health.

How to Prevent Muscle Loss on GLP-1

There are three non-negotiables I’m focusing on:

1) Adequate Protein Intake

Most women on GLP-1 are often advised to aim for 0.7–1g per pound of goal body weight (or 1.6–2.2g/kg). For many women, that’s roughly 100–150g per day.

2) Strength Training (Minimum 3x Per Week)

Resistance training signals your body: “Keep this tissue.” Without that signal, your body may shed muscle alongside fat. It doesn’t need to be extreme—just consistent.

3) Manage Cortisol & Overtraining

Consistently high stress can make blood sugar regulation harder and may increase vulnerability to breakdown over time. One tip my doctor gave me was shifting from high-stress incline sessions to walking with a weighted vest—more resistance, less overwhelm.

How I Monitor Muscle Without Spiraling

My doctor recommended a smart fitness scale weekly (not daily) so I can track trends without turning it into self-judgment.

• Lean mass trends
• Body fat percentage
• Visceral fat
• Hydration levels

The Bigger Picture

GLP-1 medications can regulate appetite and improve insulin sensitivity, but they don’t erase your responsibility to fuel and stimulate your body properly. Sustainable fat loss is slower, steadier, and supported—no starvation, no overtraining, no panic. Just the plan… and the truce.

References

• Weinheimer EM et al. Effect of weight loss on lean body mass. Am J Clin Nutr. 2010.
• Longland TM et al. Higher protein intake preserves lean mass during hypocaloric dieting. Am J Clin Nutr. 2016.
• Rosmond R. Stress and metabolic syndrome. Psychoneuroendocrinology. 2005.
• Joseph JJ, Golden SH. Cortisol and metabolic disease. Curr Diabetes Rep. 2017.
• Drucker DJ. Mechanisms of Action of GLP-1. Cell Metab. 2018.
• Nauck MA, Meier JJ. Incretin hormones. Diabetes Obes Metab. 2019.