In recent years, glucagon-like peptide-1 receptor agonists (GLP-1RAs) have emerged as powerful allies in the fight against obesity and type 2 diabetes mellitus (T2DM).

These medications, including semaglutide (Ozempic, Wegovy, Rybelsus), liraglutide (Saxenda), and tirzepatide (Mounjaro), have shown remarkable efficacy in managing these conditions.

However, while they offer substantial benefits, they also present a new set of challenges, particularly concerning nutritional health.

The Double-Edged Sword of Appetite Suppression

GLP-1RAs work by suppressing appetite and delaying gastric emptying, which can lead to significant weight loss and improved:

• Glycaemic control
• Lipid profile
• Liver function (LFTs)
• Renal (kidney) function

However, these mechanisms can also inadvertently reduce the intake and absorption of essential nutrients, potentially leading to micronutrient deficiencies.

Key Nutritional Deficiencies to Watch For

A recent analysis of studies involving 480,825 adults on GLP-1RA therapy highlighted several common nutritional deficiencies:

• Vitamin D Deficiency: The most frequently observed deficiency, affecting 7.5% of users at six months and increasing to 13.6% at twelve months.
• Iron Depletion: Users had 26%–30% lower ferritin levels compared to those on SGLT2 inhibitors. Over 60% consumed less than required calcium and iron.
• Protein and Calcium: Insufficient intake linked to lean mass loss.
• Thiamine and Cobalamin: Deficiencies increase over time.

The Importance of Nutritional Monitoring

Given these findings, it is crucial for patients on GLP-1RA therapy to undergo targeted nutritional assessments.

Healthcare providers should consider individualised laboratory evaluations to identify and address potential deficiencies early.

Moving Forward

While causality between GLP-1RA therapy and nutritional deficiencies is not fully established, these insights highlight the importance of a comprehensive approach to patient care.

As GLP-1RAs continue to rise in popularity, understanding their full impact on nutritional health becomes increasingly important.

For those managing obesity and T2DM with GLP-1RAs, staying informed and proactive can help maximise benefits while minimising potential drawbacks.

Recommended Blood Testing

A full range of blood tests is available at: www.wishingwellhealth.co.uk

We recommend:

• Nutrition Blood Test
  
• Advanced Essential Blood Test
  

Organic nutritional supplements also available.

Reference

Information based on a review of 60 studies:

Micronutrient and Nutritional Deficiencies Associated With GLP-1 Receptor Agonist Therapy: A Narrative Review

Jorge Urbina, Luis Eduardo Salinas-Ruiz, César Valenciano, Benjamin Clapp
First published: 19 January 2026

https://doi.org/10.1111/cob.70070