Weight-loss injections linked to severe nutrient deficiencies in 38% of patients

New weight-loss injections like semaglutide and tirzepatide are growing in popularity, but concerns about malnutrition risks have emerged. A recent study found that 38% of patients using these drugs showed signs of nutrient deficiencies, compared to just 9% in the control group. German health guidelines now stress the need for careful medical supervision when prescribing them for obesity treatment.

The study highlighted several nutritional shortfalls linked to GLP-1 receptor agonists. After six months, 7.5% of users developed vitamin D deficiency, rising to 13.6% after a year. Over 60% also consumed less calcium and iron than recommended, with vitamin D intake averaging just 20% of the advised amount.

Iron deficiency was particularly common, with ferritin levels dropping 26 to 30% lower than in patients on other diabetes drugs. Reduced thirst from the injections further raised dehydration risks. Protein and calcium shortages also led to muscle loss, while deficiencies in thiamine and cobalamin worsened over time. German S3 guidelines now recommend these drugs only alongside diet, exercise, and behavioural therapy. They warn that low-carb diets, often paired with the injections, can deepen nutrient gaps. However, the guidelines do not specify routine lab tests for long-term users, leaving doctors to adjust care individually.

Patients prescribed weight-loss injections must now receive dietary counselling to prevent deficiencies. The findings underscore the need for regular monitoring, particularly for vitamin D, iron, and calcium. Without proper guidance, long-term use could heighten malnutrition risks.