A new study indicates that GLP-1 medications, including semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound), may increase the risk of nutrient deficiencies among users. These drugs, typically prescribed for diabetes and obesity, often result in reduced food intake but could also impair the absorption of essential vitamins and minerals.
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The analysis, published in the February 2026 issue of Clinical Obesity, reviewed six studies involving 480,825 adults with diabetes, obesity, or both. Most findings originated from two large studies predominantly involving middle-aged and older adults. The study found that vitamin D deficiency was the most prevalent issue, impacting 13.6% of participants after 12 months, which included approximately 461,000 individuals, of whom 56% were female. Nutritional anemia was identified in 4% of participants, while deficiencies in iron and B vitamins were noted in 3.2% and 2.6%, respectively.
In a smaller study analyzing food intake among 69 GLP-1 users, it was found that 72% consumed less than the recommended amount of calcium, nearly two-thirds (64%) lacked sufficient iron, and only 1.4% met the vitamin D guidelines.
The researchers suggest that healthcare providers should consider nutritional deficiencies a common outcome of GLP-1 therapy and monitor patients' nutritional status. Dr. Robert Shmerling, senior faculty editor at Harvard Health Publishing, advises users of GLP-1 medications to ensure adequate intake of nutrients, particularly vitamin D, iron, and B vitamins, and to consider daily multivitamin supplements.