Less fat inside muscle does not necessarily mean more muscle

The short answer

Liraglutide reduced fat within thigh muscle in one MRI analysis. Muscle volume also fell, and the study did not measure strength.

What did researchers examine?

This secondary analysis included 128 adults with usable scans before and after treatment. Participants had overweight or obesity without diabetes; 92% were women.

They received daily liraglutide, targeting 3 mg, or placebo alongside diet and activity advice. Follow-up was typically 36 weeks.

What changed?

Compared with placebo, liraglutide reduced the proportion of fat within thigh muscle by an adjusted 0.24 percentage points. That is not a 24% reduction.

Thigh muscle volume was also 0.29 liters lower relative to placebo. A measure adjusted for body size did not show a clear difference between groups.

Why does that distinction matter?

Muscle fat, muscle size and muscle strength describe different things. These scans cannot tell us whether participants became stronger or moved more easily.

Only people with usable follow-up scans entered this analysis, and predominantly female participation limits generalization. This was a secondary study, not a complete treatment-benefit or safety assessment.

Novo Nordisk funded the parent trial.