Body Composition · GLP-1

GLP-1 Muscle Loss
Risk Calculator

Calculate your risk of losing lean muscle on Ozempic, Wegovy, or tirzepatide — and get a personalised plan to protect it.

Muscle Retention Score
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/100
Daily protein target
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grams/day
Lean mass at risk
—
of weight lost
Est. muscle preserved
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lbs (projected)
Your personalised recommendations
Based on published research on lean mass changes during calorie restriction and GLP-1 treatment. Individual results vary. Not medical advice.
Based on your results
Protect your muscle while losing fat
GLP-1 programs that include nutritional support help you hit protein targets and preserve lean mass. These providers include clinical guidance alongside medication.
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Yucca Health
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Oral or injectable
Strut Health
From $199/mo
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About this calculator

Why muscle loss matters on GLP-1

GLP-1 medications produce rapid weight loss — but without proper intervention, a significant portion of that weight can be lean muscle mass rather than fat. Clinical trial data shows that approximately 25 to 40% of total weight lost on semaglutide without additional intervention is lean mass. This matters beyond aesthetics: muscle tissue drives your resting metabolic rate, and losing it makes weight maintenance harder after treatment ends.

The good news is this is largely preventable. Patients who combine adequate protein intake with resistance training preserve an estimated 10 to 15% more lean mass — shifting the muscle/fat loss ratio significantly in the right direction.

Key principle: Protein and resistance training are non-negotiable during GLP-1 treatment, especially in months 1 to 6 when weight loss is fastest and muscle loss risk is highest.

How the muscle retention score is calculated

Your score is based on four evidence-based risk factors for muscle loss during calorie-restricted weight loss:

  • Age — Sarcopenia risk increases after 50 and accelerates after 65. Older patients need higher protein intake and more emphasis on resistance training to preserve the same lean mass as younger patients.
  • Protein intake relative to body weight — The primary driver of muscle retention. Research consistently shows 0.7 to 1.0g protein per pound of goal body weight is the threshold for meaningful preservation.
  • Resistance training frequency — Progressive resistance training 2 to 3 times per week sends the strongest signal to maintain muscle tissue during a calorie deficit.
  • Rate of weight loss — Faster weight loss correlates with higher lean mass loss. A pace of 0.5 to 1.0 lbs per week is associated with the best muscle preservation outcomes.

The protein target explained

This calculator uses goal body weight rather than current body weight for the protein calculation. This is intentional — as you lose weight, your protein needs decrease, and basing targets on goal weight gives a more sustainable long-term number that doesn't require constant recalculation.

The range (0.7g to 1.0g per pound) reflects different need levels. Older patients, those losing weight rapidly, and those doing significant resistance training benefit from targets at the higher end of this range.

Frequently asked questions
Yes, some muscle loss is common on GLP-1 medications. Clinical trial data shows approximately 25 to 40% of total weight lost on semaglutide without additional intervention is lean mass. However, this can be significantly reduced to 15 to 25% with adequate protein intake of 0.7 to 1.0 grams per pound of goal body weight and regular resistance training two to three times per week. Patients who maintain protein targets and strength training preserve an estimated 10 to 15% more lean mass than those relying on medication alone.
Most GLP-1 clinicians recommend 0.7 to 1.0 grams of protein per pound of goal body weight per day while on semaglutide or tirzepatide. This is significantly higher than general dietary guidelines because GLP-1 medications suppress appetite so effectively that calorie intake often drops 30 to 50%, creating risk of muscle loss without intentional protein targeting. For a 200-pound person targeting 160 pounds, that is 112 to 160 grams of protein daily. Protein adequacy is particularly important during the first 6 months when weight loss is fastest.
Resistance training two to three times per week significantly reduces muscle loss during GLP-1 treatment. Studies show patients who combine resistance training with adequate protein intake preserve approximately 10 to 15% more lean mass than those on medication alone. Cardio alone does not protect lean mass as effectively as resistance training. Compound movements such as squats, deadlifts, rows, and presses are most effective because they stimulate the largest amount of muscle tissue.
A muscle retention score of 75 or above is considered good during GLP-1 treatment, indicating low risk of significant lean mass loss. Scores above 85 are excellent and reflect patients with optimal protein intake, regular resistance training, and moderate weight loss pace. Scores below 60 indicate elevated risk and warrant immediate dietary and exercise adjustments. The score is based on four key factors: age, daily protein intake relative to body weight, resistance training frequency, and rate of weight loss per week.
Yes. Creatine monohydrate at 3 to 5 grams daily has emerging evidence for lean mass preservation during GLP-1 treatment. Creatine supports muscle protein synthesis, reduces muscle breakdown during caloric restriction, and has an excellent safety profile. Several GLP-1 clinicians now routinely recommend creatine alongside resistance training as a muscle protection strategy. It is low-cost, widely available, and well-tolerated by most patients.
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