People with higher muscle mass appear to experience slower brain ageing, according to new research presented at the Radiological Society of North America annual meeting, highlighting potential risks associated with weight-loss drugs that reduce both fat and muscle. The study, reported by the Financial Times, found that while losing visceral fat — the deep abdominal fat surrounding organs — is beneficial for brain health, maintaining muscle is a crucial contributor to cognitive vitality.
The research examined 1,164 healthy adults, with an average age of just over 55, using structural MRI scans to estimate brain age alongside whole-body MRI scans to assess muscle mass and visceral fat levels. An artificial intelligence algorithm analyzed relationships between these factors and found that participants with more muscle had lower brain ages, while a lower visceral fat-to-muscle ratio also correlated with better brain outcomes. Subcutaneous fat beneath the skin, however, showed no significant link to brain age.
Cyrus Raji, senior author and associate professor of radiology and neurology at Washington University School of Medicine, emphasized the implications for weight-loss therapies. “Losing fat — especially visceral fat — while preserving muscle volume would have the best benefit on brain ageing and brain health,” he said. The study may inform future research to determine optimal dosing of GLP-1 drugs, such as Ozempic, Wegovy, and Mounjaro, which have become widely used for obesity but can lead to the loss of lean body mass.
GLP-1 medicines were originally developed to treat diabetes, but millions now use them to lose weight. Studies suggest lean body mass can account for 15 to 40% of total weight lost with these treatments. Many drugmakers are developing next-generation obesity therapies aimed at better preserving muscle while reducing fat.
Henry Chung, a lecturer in physiology and nutrition at Essex University, described the study as “powerful” due to its large sample size and the combination of MRI scans with AI-calculated brain ages. He noted that the findings align with other research linking greater muscle mass to healthier metabolism, reduced inflammation, and slower physical ageing. “This specific research definitely strengthens the argument for being cautious with GLP-1 treatments,” he said, underscoring the importance of resistance training and adequate protein intake to protect muscle during weight-loss therapy.
The findings suggest that strategies targeting both fat reduction and muscle preservation could offer the most benefit for long-term brain and body health, raising critical considerations for the millions using GLP-1 medications.
