Children taking GLP-1 medicines, which copy a gut hormone's fullness signal, need nutrition support when appetite falls. New research on GLP-1 nutritional deficiencies—children were the focus—puts a number on that concern. About 1 in 6 young patients received a deficiency or related-complication diagnosis within a year. A deficiency means the body lacks an essential nutrient.
The finding deserves attention. It does not prove that the medicines caused those diagnoses.
GLP-1 nutritional deficiencies—children in the new study
As of September 30, 2026, the day this article was written, a September 17 study in Childhood Obesity has highlighted a gap in early nutrition care. Northwestern's September 21 release brought the findings to wider attention.
Researchers examined insurance billing records for 2,031 U.S. patients ages 10–17 who started a GLP-1 medicine. None had a recorded deficiency or related complication during the previous six months. The records covered 2017–2022, rather than today's prescribing patterns.
| Diagnosis recorded after treatment began | Within 180 days | Within one year |
|---|---|---|
| Any nutrient deficiency or related complication | 10.2% | 16.9% |
| Vitamin D deficiency | 7.6% | 12.4% |
The paper also reported nutritional anemia in 1.55% within a year. That means too few healthy red blood cells because of nutrient shortages.
Nutrition visits were uncommon early on. Table 4 reports counseling or nutrition therapy for 5.8% within 30 days and 23.3% within 180 days. These are recorded services; ordinary food advice may not produce a separate billing claim.
What this means for an adult starting semaglutide
For adults starting semaglutide, a GLP-1 medicine, the useful lesson is to plan for smaller meals before hunger drops. A lower number on the scale cannot show whether meals still supply enough protein, vitamins, and minerals.
Adult evidence already points to the same concern. A 2025 study in Obesity Pillars examined 461,382 adults starting GLP-1 treatment. Just over 1 in 5, or 22.4%, had a deficiency or related-complication diagnosis within a year. Most had type 2 diabetes, a condition that raises blood sugar. That percentage is not a forecast for every adult seeking weight treatment.
Both studies were funded by Abbott. They provide a reason to assess nutrition, rather than evidence that a particular supplement prevents deficiencies.
Promise serves adults age 18 and older. Children need a care team focused on growth and development; the product options here relate to adult care.
Adult nutrition counseling: protein, vitamin D, iron, and B12
The 2025 joint nutrition advisory in the American Journal of Clinical Nutrition recommends assessing eating patterns before treatment and revisiting them during care. It emphasizes nutrient-rich foods, adequate protein, and strength exercise to support muscle. A registered dietitian, a trained nutrition professional, can make that plan fit someone's health and ordinary meals.
| Nutrient | Why an adult care team pays attention | Food sources to discuss |
|---|---|---|
| Protein | Supplies material for maintaining muscle | Eggs, yogurt, fish, tofu, beans, or lentils |
| Vitamin D | Helps the body absorb calcium for bone health | Fatty fish and milk or plant drinks with added vitamin D |
| Iron | Helps blood carry oxygen | Meat, beans, lentils, and cereals with added iron |
| Vitamin B12 | Supports nerves and healthy red blood cells | Animal foods and foods with added B12 |
Those are conversation topics, not a supplement prescription. Food intake, symptoms, existing conditions, and medicines help determine which tests or supplements make sense. Protein needs also vary; a fixed target copied from someone else can miss important health differences.
The same planning matters for adults considering tirzepatide, another medicine that affects fullness signals. It is a different treatment, and the pediatric study did not compare it with semaglutide. The semaglutide meal-plan guide offers an adult food framework that can be personalized with a care team.
What the children's study does not establish
A billing-code study counts diagnoses and services recorded for insurance. It does not measure every meal or blood nutrient level. An unrecorded deficiency could have existed before treatment began. There was no comparison group of children who weren't taking a GLP-1 medicine.
The sample also wasn't a study of modern Wegovy treatment alone. Nearly 4 in 5 patients used liraglutide, another GLP-1 medicine: 78.6%, compared with 9.1% using semaglutide.
Children who received nutrition counseling had more recorded deficiencies. The authors explain that a deficiency may prompt a referral, or extra testing may uncover one. That pattern cannot show that counseling causes harm or prevents deficiencies.
The findings also leave the age limits unchanged. The Wegovy prescribing information, marked “Revised: 06/2026,” covers injection treatment for obesity from age 12. The Zepbound label, marked “Revised: 8/2026,” covers adults; its safety and effectiveness in children have not been established. The separate semaglutide for children guide explains the younger-child trial news.
What adult follow-up needs to cover
A useful follow-up looks beyond weight. It can review what meals now look like, whether nausea is crowding out food, and whether strength or daily energy has changed. Food access matters too: a plan has to fit the person's budget, schedule, and preferences.
Persistent tiredness deserves assessment instead of an automatic vitamin prescription. The guide to semaglutide and tiredness covers other possible causes. Repeated vomiting, difficulty keeping fluids down, or much less urination needs prompt medical attention.
Some compounded GLP-1 preparations add a vitamin such as B12. An added vitamin is not evidence that a preparation prevents nutrient deficiencies. It does not replace an assessment of the rest of someone's diet.
Adult prescription decisions
Through Promise, semaglutide is dispensed as a compounded medication, which is different from an FDA-approved product: the formulation offered here is not FDA-approved. Compounding means a pharmacy prepares a medication for a particular prescription. FDA explains that compounded drugs do not receive its safety, effectiveness, or quality review before marketing.
A licensed provider may still prescribe a compounded formulation when appropriate; that decision is between the patient and the doctor. At Promise, a licensed provider reviews every request, and not everyone qualifies.
What to watch next
The next useful research would follow children on today's treatments, measure food intake and nutrient levels, and include a comparable untreated group. Studies assigning early nutrition support would help show whether that support changes outcomes.
For adults already discussing treatment, the immediate question is practical: who will review nutrition when appetite changes, and how will that review happen? A prescription and a nutrition plan need to stay connected throughout care.
