Multivitamin Impact on Micronutrient Status in GLP-1 Users: A Randomized Trial (VITAGLP)

Erasmus University

Status: Invitation-only

Conditions: Weight Loss; Nutritional Deficiencies; Obese Patients; GLP - 1

Treatments: Dietary Supplement: Multivitamin Supplementation; Other: Placebo

Study type: Interventional

Funder types: Other

Identifiers

NCT07234916

ABR 2025 GLP (Other Identifier)

GLP-1-RCT-2025

Details and patient eligibility

About

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.

Enrollment: 246 estimated patients

Sex: All

Ages: 18 to 70 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• 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 criteria

• Known allergy or hypersensitivity to any components of the multivitamin supplement
• Current use of other vitamin or mineral supplements
• Pregnancy or planning pregnancy during the study period
• Patients who follow a vegan diet.
• Active malignancy or ongoing cancer treatment
• Severe kidney disease (eGFR <30 mL/min/1.73m²)
• Severe liver disease (Child-Pugh C)
• History of metabolic bariatric surgery
• Participation in other clinical trials within the past 3 months
• Any condition that, in the investigator's opinion, would interfere with study participation or compromise patient safety

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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246 participants in 2 patient groups, including a placebo group

Group A (Multivitamin Supplementation)

Experimental group

Description:

Participants in this group will receive a daily multivitamin supplement formulated to provide comprehensive micronutrient support. The supplement will be taken once daily with a meal for the 12-month intervention period following randomization.

Treatment:

Dietary Supplement: Multivitamin Supplementation

Group B (Placebo)

Placebo Comparator group

Description:

Participants in this group will receive a matching placebo that is identical in appearance, taste, and packaging to the active multivitamin supplement. The placebo will be taken once daily with a meal for the 12-month intervention period following randomization.

Treatment:

Other: Placebo