Semaglutide Plus Bariatric Surgery Led to Severe Nerve Damage From Nutrient Deficiencies | Research

The takeaway

A 39-year-old man developed severe lower body weakness and nerve damage from thiamine and vitamin E deficiencies while on semaglutide after bariatric surgery, highlighting risks of combining weight-loss therapies.

Thiamine + vitamin E deficiency → nerve damage
Combined appetite suppression from semaglutide plus malabsorption from bariatric surgery caused severe micronutrient deficiencies and lumbosacral polyradiculopathy

What the researchers found

A 39-year-old male on semaglutide (1.7 mg/week) following transoral outlet reduction surgery presented with severe bilateral lower extremity weakness, loss of reflexes, and sensory impairment. Laboratory testing revealed thiamine and vitamin E deficiencies. MRI showed cauda equina nerve root enhancement without structural abnormalities. He was diagnosed with lumbosacral polyradiculopathy due to micronutrient deficiencies.

Symptoms developed over 3 months and worsened after semaglutide dose increase. Treatment included semaglutide discontinuation, thiamine and vitamin E supplementation, and inpatient rehabilitation. Motor and sensory symptoms improved over the following month.

Why it matters

Millions of people are now using GLP-1 receptor agonists like semaglutide, and many have a history of or are considering bariatric surgery. This case highlights a potentially dangerous blind spot: there are established nutritional monitoring guidelines for bariatric surgery patients but almost none for GLP-1RA users, and no guidelines at all for patients using both. As combination weight-loss approaches become more common, nutrient monitoring becomes critical.

How the study worked

Single clinical case report. The patient underwent physical examination, laboratory serum testing for micronutrients, and lumbar MRI. Diagnosis was made based on the combination of neurological findings, documented nutrient deficiencies, and absence of structural abnormalities on imaging.

What this study cannot tell us

This is a single case report, representing the lowest level of clinical evidence. The relative contribution of bariatric surgery versus semaglutide to the nutrient deficiencies cannot be determined. The patient's dietary intake and compliance with post-surgical nutrition recommendations were not detailed. It's unclear whether semaglutide alone (without prior surgery) would pose similar risks. Long-term neurological outcomes were not reported.

How to read the evidence

This is a single case report published in an endocrine case reports journal. While it provides an important safety signal, it cannot establish incidence rates or causal mechanisms for the observed complications.

When this study was published

Published in 2025, this is a very timely case report addressing a rapidly emerging clinical scenario as GLP-1 agonist use expands among patients with bariatric surgery histories.

The bigger picture

The explosion of GLP-1 receptor agonist prescribing has created new clinical scenarios that weren't anticipated in original trials. Combining potent appetite suppressants with malabsorptive surgeries creates compound nutritional risk. This case is likely a sentinel event — as more post-bariatric patients receive semaglutide, similar complications may emerge, underscoring the need for specific monitoring guidelines.

Questions still open

Should routine micronutrient screening be required for all patients starting GLP-1 receptor agonists, especially those with a history of bariatric surgery?
Can semaglutide alone cause clinically significant nutrient deficiencies through appetite suppression, even without bariatric surgery?
What is the safe minimum time interval between bariatric surgery and initiating GLP-1 receptor agonist therapy?

Common questions

Why would semaglutide combined with bariatric surgery cause nutrient deficiencies?

Bariatric surgery physically changes the digestive tract, reducing the body's ability to absorb nutrients from food. Semaglutide dramatically reduces appetite, meaning patients eat significantly less. Together, less food intake plus reduced absorption creates a double hit that can lead to dangerous deficiencies in essential vitamins and minerals.

What are the warning signs of nutrient deficiencies while on weight-loss treatments?

Key warning signs include progressive weakness (especially in the legs), numbness or tingling, difficulty walking, fatigue, and vision changes. If you're on a GLP-1 agonist after bariatric surgery and notice any of these symptoms developing over weeks to months, seek medical attention promptly for nutritional evaluation.

Read the original research

Severe lumbosacral polyradiculopathy secondary to micronutrient deficiencies in a patient on semaglutide therapy following bariatric surgery.

Endocrinology, diabetes & metabolism case reports, 2025(3)

View on PubMed ↗Publisher’s paper ↗

Citation

Donigan, Emma C; Ingersent, Elizabeth; Wanberg, Erik J; Jegen, Dominika A; Passmore, Rachael. (2025). Severe lumbosacral polyradiculopathy secondary to micronutrient deficiencies in a patient on semaglutide therapy following bariatric surgery.. Endocrinology, diabetes & metabolism case reports, 2025(3). https://doi.org/10.1530/EDM-25-0072