Pharmacists can help patients maintain muscle mass, meet their protein needs, and prevent nutritional deficiencies through evidence-based guidance that supports better overall health.
Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) such as semaglutide (Ozempic, Wegovy) and tirzepatide (Zepbound, Mounjaro) have transformed the approach to managing obesity and diabetes, resulting in significant weight loss and improved cardiovascular outcomes for patients. However, as with any rapid weight-loss strategy—including bariatric surgery and extreme low-calorie restricted diets—this process may be accompanied by lean muscle loss, inadequate protein intake, and nutrient deficiencies.1,2
Pharmacists are in a key position to support patients by offering evidence-based nutrition information that enhances therapy effectiveness and reduces potential health risks. By reinforcing protein goals, addressing micronutrient gaps, and encouraging healthy dietary patterns, pharmacists can support better health outcomes during GLP-1 therapy.
Research has shown that weight loss from GLP-1 RAs may include loss of lean muscle mass.3 These concerns are not unique to GLP-1 RA therapy but are inherent to any rapid weight-loss intervention and warrant careful monitoring by health care professionals. Preserving muscle mass is critical to maintaining metabolic health and physical function.4 Evidence supports recommending protein intake of 1.2 to 2.0 g/kg/day to reduce muscle wasting.5 Despite this, only about 43% of patients meet their minimum protein needs during GLP-1 therapy.5
Pharmacists should reinforce protein targets and encourage patients to choose high-quality protein sources such as lean meats, legumes, and dairy.6 Additionally, resistance training combined with adequate protein intake further aids muscle preservation.1,5,7 When comparing protein intake alone vs protein augmented with resistance training, significant improvements in muscle strength occurred only when resistance training was added.4
GLP-1 therapy can reduce appetite and cause gastrointestinal (GI) adverse effects such as nausea and vomiting, which may contribute to poor nutrient intake.7,8 Prevalence data already show high rates of deficiency in populations with obesity and type 2 diabetes—for example, vitamin D (80% to 90%), vitamin C (35% to 45%), and selenium (58%) in obesity, and vitamin B12 (22%) in diabetes.9 Other common deficiencies include calcium, magnesium, iron, and fat-soluble vitamins (A, D, E, K).7,9,10 Insufficiencies can occur before a true clinical deficiency and may not be detected by standard laboratory tests.
GLP-1 therapy may exacerbate already existing deficiencies in a patient when food intake is decreased. A 2025 multisociety advisory from leading nutrition and obesity organizations recommends that patients starting GLP-1 therapy receive a baseline nutrition and micronutrient assessment to identify deficiencies early and guide individualized recommendations.1 Pharmacists should recognize these nutrient gaps as contributors to fatigue, reduced immune function, and poor glycemic control. Asking about dietary intake during counseling and recommending appropriate laboratory testing or supplements can help bridge these gaps. Pharmacists are well-positioned to incorporate evaluation of micronutrient deficiencies into their community practice.
The Mediterranean diet, rich in whole grains, fruits, vegetables, nuts, legumes, olive oil, and fish, has proven cardiovascular benefits that complement GLP-1 therapy.9,11,12 Results from the landmark PREDIMED trial (ISRCTN35739639) showed a 30% relative risk reduction in major cardiovascular events in patients on a Mediterranean diet supplemented with extra-virgin olive oil or nuts.13 Results from other meta-analyses confirmed reductions in myocardial infarction, stroke, and risk of cardiovascular death in high-risk adults on the diet.11 For patients with type 2 diabetes, the Mediterranean diet can improve glycemic control and lower systolic blood pressure levels.9 Pharmacists can encourage this dietary pattern to support weight loss, cardiovascular health, and metabolic outcomes during GLP-1 use.
GLP-1 RAs are powerful tools for improving weight and cardiometabolic outcomes, but without proper nutrition support, patients may face preventable muscle loss and nutrient deficiencies.1,3,5,7 Pharmacists play a role in bridging the gap between pharmacologic treatment and sustainable lifestyle change. By emphasizing adequate protein, monitoring for micronutrient gaps, and encouraging evidence-based dietary patterns, pharmacists can help patients maximize the benefits of GLP-1 therapy while supporting long-term health.9,12,13
Abigail Knapp, BSPS, is a fourth-year pharmacy student at Cedarville University in Ohio who is interested in ambulatory care and functional medicine.
Melody Hartzler, PharmD, BCACP, BC-ADM, ABAAHP, is a board-certified ambulatory care pharmacist and a highly recognized expert in integrative and functional pharmacy practice.
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