Am I losing muscle on Ozempic / Wegovy, and how do I tell?

This is the quiet fear in every GLP-1 forum, and it's a legitimate one. When you lose weight quickly — which is exactly what these drugs are good at — a meaningful share of that loss can come from lean muscle rather than fat, especially if your protein intake has cratered (appetite suppression makes this easy) and you're not doing any resistance training.

The classic warning signs: the scale is dropping nicely, but you feel weaker, flatter, more tired, or you've gone 'skinny-fat' — smaller but softer. If the number on the scale is the only thing improving while your strength and shape are going the wrong way, muscle loss is the likely culprit.

The fix is straightforward but non-negotiable: hit a protein target (around 1.6 g/kg of your goal body weight is a common, evidence-based aim), lift weights two to three times a week so your body has a reason to hold onto muscle, and don't lose faster than roughly 1% of body weight per week. The drug creates the calorie deficit; your job is to aim that deficit at fat.

Crucially, you have to measure body composition, not just weight, to know it's working. Calqulate.net's free Body Fat and Lean Body Mass calculators let you watch muscle versus fat, and the GLP-1 Progress Tracker in Calqulate Vitals flags when you're losing weight too fast for it to be all fat.