Nearly 1 in 6 children on weight-loss jabs developed a nutrition problem within a year
What happened
GLP-1 medicines are the injections many people know by brand names linked to weight loss and type 2 diabetes. They work partly by making you feel full sooner and for longer. In adults they have been studied a great deal. In children and teenagers, much less. A new study has looked at what happens to younger patients. Researchers examined health records for 2,031 people aged between 10 and 17 in the United States. All of them had just started a GLP-1 medicine. None of them had a history of nutritional problems before they began. Within one year, 16.88% of them, close to one in six, were diagnosed with at least one nutritional deficiency or a related complication. The most common problem by far was vitamin D deficiency, found in 12.4%. Nutritional anaemia affected 1.55% and iron-deficiency anaemia 1.44%. The study also looked at whether these young patients were given dietary advice. Only 5% received nutrition counselling within 30 days of starting treatment. Fewer than a quarter had received it within six months. The work was published in the journal Nutrition in Clinical Practice in September 2026 by Kirk W. Kerr and colleagues, and was reported in the UK by The Pharmaceutical Journal.
Why this matters
Eating less is the point of these medicines. Eating less of everything is not. Children and teenagers are still growing. Bones are still laying down the mineral they will carry for life. Blood volume is expanding. The body's demand for iron, calcium, vitamin D and protein is higher during these years than it will be later on. A medicine that reduces appetite lands differently in a 14-year-old than in a 50-year-old. The second finding is arguably the more important one. The deficiencies are manageable. Vitamin D deficiency is easy to test for and easy to treat. But you have to look for it. Only 5% of these young patients got dietary advice in the first month. That is the gap. Not the medicine itself, but the care wrapped around it. In the UK, GLP-1 medicines for weight management in under-18s are prescribed in specialist services, under strict NICE criteria, not handed out routinely. That is a genuine safeguard. But the number of young people on these treatments is growing here too, and a growing private market means not every young patient is inside a specialist team.
What the evidence actually says
Be careful with what this study can and cannot tell you. It is a review of health records, not a trial. There was no comparison group of similar young people who were not taking a GLP-1 medicine. That matters, because vitamin D deficiency is already common in young people, especially in northern countries with little winter sunlight. Some of that 12.4% might have shown up anyway. There is also a detection effect. Someone who has just started a new medicine gets more blood tests. More testing finds more problems. A teenager not on treatment might have exactly the same low vitamin D level and never be tested. The medicines used were mostly liraglutide (78.6%), then dulaglutide (10.4%) and semaglutide (9.1%). That mix reflects US prescribing for this age group and may not match UK practice. And it was a one-year window. It tells us nothing about what happens over five years. So the honest reading is this. The study does not prove GLP-1 medicines cause nutritional deficiencies in children. It does show that among young people starting them, nutritional problems were common enough to be worth routine checking, and that checking and advice were mostly not happening.
Qurexa perspective
This is a story about the bit that happens after the prescription is written, which is the part we see every day. A medicine only works if it is taken correctly and reviewed regularly. Vitamin D is one of the clearest examples. It is inexpensive, widely available and easy to supplement, and the UK already advises that everyone consider a daily 10 microgram vitamin D supplement between October and early March, because we simply do not get enough sunlight. If a young person in your family is on a GLP-1 medicine, their pharmacist is a genuinely useful and free source of advice on supplements, timing, side effects and what to watch for. You do not need an appointment to ask. That conversation is worth having before a problem shows up, not after.
Practical advice
If your child or teenager has been prescribed a GLP-1 medicine, here is what is reasonable to do. Ask the prescribing team directly: what will you monitor, how often, and what blood tests will be done? A good specialist service will already have an answer. Ask for dietitian input. The study found most young patients never got it. You are allowed to ask. Protect protein, iron and calcium in a smaller appetite. When someone eats less overall, what they do eat has to work harder. Eggs, dairy, beans, fish and meat go further than snacks. Follow the UK vitamin D advice: a daily 10 microgram supplement in autumn and winter for everyone over one year old, and all year round for people who get little sunlight. Watch for tiredness that is out of proportion, breathlessness on stairs, pale skin, or bone and muscle aches. These can be signs of anaemia or low vitamin D. Report them. Do not stop the medicine on your own if you are worried. Speak to the prescriber or a pharmacist first.
What to know
In a study of 2,031 young people aged 10 to 17 starting GLP-1 medicines, 16.88% developed a nutritional deficiency or related problem within a year, most often low vitamin D. Only 5% received nutrition advice in the first month. The study cannot prove the medicines caused the deficiencies, and it was done in the United States, where prescribing differs from the UK. What it does show clearly is a gap in follow-up care that is easy and cheap to close. If a young person you care for is on one of these medicines, the useful questions are about monitoring, dietitian access and vitamin D. Ask them early. Sources: Nutrition in Clinical Practice, Kerr KW et al., 'Nutritional Deficiencies, Complications, and Nutrition Therapy/Counseling in Pediatric Patients Using GLP-1 Receptor Agonists', 2026, https://journals.sagepub.com/doi/10.1177/21532176261486979 ; The Pharmaceutical Journal, 'Children taking GLP-1s can be at risk of nutritional deficiencies, study finds', September 2026, https://pharmaceutical-journal.com/article/news/children-taking-glp-1s-can-be-at-risk-of-nutritional-deficiencies-study-finds ; NHS, 'Vitamin D', https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/ This article is for general information and does not replace advice from a doctor, pharmacist or other qualified healthcare professional.
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