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Around one in six children taking glucagon-like peptide-1 receptor agonists (GLP-1s) experiences a nutritional deficiency within the first year of treatment, according to the results of a US study.
Publishing their findings in Childhood Obesity on 17 September 2026, researchers analysed data from 2,031 patients in the United States aged between 10 years and 17 years, who had been started on GLP-1 therapy and had no prior history of nutritional deficiency.
Of these patients, nearly two thirds (62.6%, n=1,271) had obesity, more than two-thirds (67.2%, n=1,365) had a diagnosis of type 2 diabetes mellitus, a small proportion (5.1%, n=104) had prediabetes, and more than one-quarter (27.7%, n=563) had no recorded diabetes diagnosis.
The patients’ mean age was 15 years, while nearly two-thirds (61.5%, n=1,249) of participants were female. Liraglutide was the most commonly initiated GLP-1RA (78.6%) during the study, followed by dulaglutide (10.4%) and semaglutide (9.1%).
Within 180 days of beginning GLP-1RA treatment, one in ten (10.2%, n=207) patients were diagnosed with at least one nutritional deficiency, which increased to more than one in ten (16.8%, n=341) after one year, the researchers found.
The researchers also noted that the most frequently observed nutritional deficiency was vitamin D deficiency, with more than one in ten (12.4%, n=252) patients being diagnosed with this after 365 days of treatment, while the most common deficiency-related complication was nutritional anaemia, with a small proportion of patients (1.55%, n=31) diagnosed with this after one year.
These findings are consistent with previous studies linking GLP-1RA use in adults to reduced dietary intake and increased risk of micronutrient inadequacies, the study authors said.
They added: “Given the heightened nutritional needs of children and adolescents, proactive nutritional management at the time of GLP-1RA initiation may play a critical role in improving treatment safety, supporting growth and development, and promoting more favourable long-term health outcomes.”
In addition, less than one-quarter (23.3%, n=473) of the patients in the study had received nutrition therapy/counselling within 180 days of initiation, the researchers found.
Study author Justin Ryder, vice chair of research for the Department of Surgery at Ann and Robert H. Lurie Children’s Hospital of Chicago, said: “As appropriate paediatric use of GLP-1s becomes more widespread, we need to understand the risks during periods of rapid growth and pubertal development.”
Commenting on the study, Sukhi Basra, vice chair of the National Pharmacy Association, who also runs a weight-loss clinic, noted that in the UK only liraglutide (Saxenda; Novo Nordisk) is licensed for adolescents aged between 12 years and 17 years with a BMI of 30 or above, a body weight of over 60kg and only as part of a specialist paediatric weight management service.
“Semaglutide and tirzepatide remain adult-only medicines here. So this isn’t a case of GLP-1s broadly available to under-18s; it’s one specific medicine, in one specific licensed pathway, with wraparound multidisciplinary support built in by design,” she added.
“Within specialist paediatric services, dietetic and nutritional input isn’t an add-on: it’s part of the fabric of care from day one, because they’re not just treating a number on a scale, they’re safeguarding a child’s growth and development. What this study tells us isn’t new to anyone practising properly; it’s a reminder of why that structure exists, and why it must never be diluted, whatever setting a young person is being cared for in.”
Basra added: “I haven’t seen significant demand from under-18s in my own clinic, and given how narrow and specialist-led the UK pathway rightly is, I wouldn’t expect to.
“If anything, this study is a useful prompt to make sure that specialist infrastructure stays properly resourced as demand for GLP-1s grows more broadly.”
