GLP-1 medications like semaglutide and liraglutide have become go-to tools for managing obesity and type 2 diabetes in children — but a new study published in Childhood Obesity suggests they may come with an underappreciated nutritional downside. Analyzing national claims data from over 2,000 children ages 10–17, researchers found that 16.8% were diagnosed with a nutritional deficiency within the first year of starting a GLP-1 drug.

Vitamin D deficiency was the most common issue (12.4%), a particularly worrying finding given that adolescence is a critical window for bone development, growth, and puberty. The concern is compounded by the fact that GLP-1s suppress appetite — potentially reducing intake of key nutrients like iron and calcium at exactly the wrong time.

By the Numbers

• 16.8% of children developed a nutritional deficiency within one year of starting GLP-1 therapy
• 12.4% were diagnosed with vitamin D deficiency specifically
• Only 5% received nutritional counseling within 30 days of starting treatment
• Fewer than 25% received counseling within 6 months
• Liraglutide accounted for 78.6% of prescriptions; semaglutide for 9.1%

Why it matters: As GLP-1 prescriptions for children grow, clinicians need to build nutritional monitoring and counseling into treatment plans from the start — not as an afterthought after deficiencies appear. The stakes during adolescent development are simply too high to wait.