Multivitamins for Adults With Obesity Who Take GLP-1 Weight Loss Medicines
Tests a multivitamin versus placebo on vitamin levels in adults taking GLP-1 medicines.
Plain-language title generated from the registry record
Registry title: Multivitamin Impact on Micronutrient Status in GLP-1 Users: A Randomized Trial
Key facts
- Where
- Amersfoort and Rotterdam, NetherlandsSee the 2 sites
Could this be for you?
Answer for yourself. This is not a decision: only the study team can say whether you can take part.
- Are you between 18 and 70 years old?
Source: NCT07234916, who can take part
Where in Netherlands
- WeightWorks ClinicsAmersfoort, NetherlandsNo longer taking part
- Erasmus MCRotterdam, NetherlandsNo longer taking part
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Trial details
- Who runs it
- Erasmus Medical Center
- Trial code
- NCT07234916
- Record updated
- 19 November 2025
- Original description
Rationale: Glucagon-Like Peptide-1 (GLP-1) receptor agonists have emerged as effective treatments for obesity and associated medical conditions. However, patients may be at risk of micronutrient deficiencies during therapy due to reduced appetite, altered gastrointestinal physiology, and weight loss. Multivitamin supplementation is commonly prescribed to mitigate these risks, but the necessity and efficacy of multivitamin use in GLP-1 users remain debatable, as some clinicians advocate for routine supplementation while others do not.Read full original descriptionShow less
The Impact of Multivitamin Supplementation on Micronutrient Levels in GLP-1 Users: A Randomized, Double-Blind, Placebo-Controlled Trial
Rationale: Glucagon-Like Peptide-1 (GLP-1) receptor agonists have emerged as effective treatments for obesity and associated medical conditions. However, patients may be at risk of micronutrient deficiencies during therapy due to reduced appetite, altered gastrointestinal physiology, and weight loss. Multivitamin supplementation is commonly prescribed to mitigate these risks, but the necessity and efficacy of multivitamin use in GLP-1 users remain debatable, as some clinicians advocate for routine supplementation while others do not.
Objective: To assess the differences in micronutrient levels between patients who use multivitamin supplements while on GLP-1 therapy and those who do not, to provide evidence on the necessity and benefits of supplementation.
Study Design: Randomized, double-blind, placebo-controlled trial. Study Population: Adults with obesity (BMI ≥30 kg/m² or ≥27 kg/m² with obesity-associated medical problems) currently using GLP-1 receptor agonists for at least 3 months with stable dosing.
Intervention:
* Group A (Intervention): Multivitamin supplementation while on GLP-1 therapy * Group B (Control): Matching placebo while on GLP-1 therapy Main Study Parameters/Endpoints: The primary outcomes are the differences in serum levels of Vitamin B12, Vitamin D, and Ferritin between the multivitamin and placebo groups after 12 months of supplementation while on GLP-1 therapy.
Nature and Extent of the Burden and Risks: Participants will undergo blood sampling at four timepoints: baseline (before starting GLP-1 therapy), at randomization (3 months of stable GLP-1 therapy), and at 6 and 12 months post-randomization. The risks associated with the study are minimal and primarily related to blood sampling and potential side effects of multivitamin supplementation. The burden includes time commitment for study visits and daily supplement intake.
Inclusion: Age ≥18 to 70 years; Start with the use of Tirzepatide GLP-1 receptor agonists and for at least 3 months with stable dosing before randomization; BMI ≥30 kg/m² or ≥27 kg/m² with obesity-associated medical problems (such as type 2 diabetes, hypertension, or dyslipidemia) at the start of GLP-1 therapy; Willing and able to provide informed consent; Able to comply with study procedures and follow-up visits; Own vitamins should be completely discontinued 2 weeks before the start.
Exclusion: Known allergy or hypersensitivity to any components of the multivitamin supplement; Active malignancy or ongoing cancer treatment; Severe liver disease (Child-Pugh C); History of metabolic bariatric surgery; Any condition that, in the investigator's opinion, would interfere with study participation or compromise patient safety; Severe kidney disease (eGFR <30 mL/min/1.73m²); Current use of other vitamin or mineral supplements; Pregnancy or planning pregnancy during the study period; Patients who follow a vegan diet; Participation in other clinical trials within the past 3 months.