A recent large-scale retrospective study by Butsch et al. (2025), sheds critical light on an often-overlooked aspect of GLP-1 receptor agonist (GLP-1RA) therapy: the risk of micronutrient deficiencies and muscle loss. 

Study Overview

The analysis included over 460,000 U.S. adults initiating GLP-1RA therapy (2017–2022), with 80.5% diagnosed with type-2 diabetes and 44.9% with obesity. The medications studied included dulaglutide (38.4%), semaglutide (28.8%), and liraglutide (28.4%).  

To isolate the effect of GLP1 medication, the researchers compared people using GLP-1 medication with similar people who only used metformin (another diabetes medicine). They made sure both groups were alike in age, health, and other factors. 

To assess the role of dietician care, they looked at the results separately for those who had seen a dietitian and those who hadn’t.  

Clinical Implications

GLP-1RA users are at higher risk for deficiencies compared to similar patients on metformin alone. This highlights the need for:

• Routine monitoring of key micronutrients during GLP-1 treatment. 

• Timely use of nutritional therapy with fiber-rich, adequate protein and micronutrient content may help optimize nutritional status, mitigate loss of muscle mass, and improve overall health.

The authors advocate for integrating dietitians into obesity care, emphasizing individualized protein intake (1.2–1.5 g/kg/day where appropriate) and resistance-based physical activity to mitigate muscle loss. 

Underestimation of Nutritional Risks

The true extent of nutritional deficiencies and muscle loss in GLP-1RA users is likely underestimated in this study, as the authors themselves acknowledge. The study relied on claims data, which only captured diagnosed and billed deficiencies — missing over-the-counter supplement use, out-of-pocket dietitian visits, and subclinical cases. Moreover, only 28.8% of patients used semaglutide (with others on less potent medication) and less than half had obesity, meaning actual deficiency risks in real-world practice may be significantly higher. 

Why This Matters

These findings likely represent just the tip of the iceberg, reinforcing the need for proactive screening, nutrition support, and multidisciplinary care in patients receiving GLP-1 therapy.

Take-Home Message

While GLP-1 receptor agonists are highly effective for weight and glycemic control, they can silently contribute to micronutrient deficiencies and muscle loss—risks that are often underdiagnosed and likely underestimated. Routine nutritional screening, early dietitian involvement, and individualized supplementation strategies should be integrated into care pathways to safeguard long-term health outcomes in patients on GLP-1 therapy.

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