A 39-year-old man experienced severe weakness and nerve damage after taking semaglutide (a popular weight loss medication) following stomach surgery. Doctors discovered he had dangerous deficiencies in thiamine and vitamin E—nutrients his body couldn’t absorb properly. When he stopped the medication and started taking supplements, his symptoms improved. This case highlights an important warning: when people combine weight loss surgery with weight loss drugs, they need extra careful monitoring for nutritional problems that could damage their nerves. Doctors need better guidelines to protect patients using multiple weight loss methods together.

The Quick Take

  • What they studied: What happens when someone takes semaglutide (a weight loss injection) after having weight loss surgery, and whether this combination increases the risk of dangerous nutrient deficiencies.
  • Who participated: One 39-year-old man who had stomach surgery and then started taking semaglutide injections for weight loss.
  • Key finding: The patient developed severe nerve damage caused by deficiencies in two important vitamins (thiamine and vitamin E). His symptoms improved after stopping the medication and taking vitamin supplements.
  • What it means for you: If you’re considering weight loss surgery or taking weight loss medications like semaglutide, especially if combining both treatments, ask your doctor about regular nutrient testing. This case suggests the combination may increase risks, though more research is needed. Don’t stop medications without medical guidance.

The Research Details

This is a case report—a detailed medical story about one patient’s experience. Doctors described what happened to a 39-year-old man step-by-step: his symptoms, test results, imaging scans, and treatment. He had undergone a type of stomach surgery called transoral outlet reduction, then started taking semaglutide (brand name Ozempic or Wegovy) for weight loss. Over three months, he developed severe weakness in his legs and couldn’t walk. When doctors increased his semaglutide dose, his symptoms got worse.

The doctors performed blood tests, which revealed he was severely deficient in thiamine (vitamin B1) and vitamin E. Brain and spine imaging showed some nerve inflammation but no major structural problems. Based on these findings, they concluded his nerve damage was caused by the vitamin deficiencies, not by a physical problem in his spine.

The treatment was straightforward: stop the semaglutide, start taking thiamine and vitamin E supplements, and do physical therapy. The patient improved significantly over the next month.

This case matters because semaglutide and similar medications are becoming very popular for weight loss, and many people are combining them with weight loss surgery. Doctors have good guidelines for monitoring nutrients after weight loss surgery alone, but they don’t have clear guidelines for people using both treatments together. This case suggests the combination might be riskier than either treatment alone.

This is a single case report, which is the lowest level of scientific evidence. It describes one person’s experience, not a pattern across many people. However, it raises an important safety concern that doctors should take seriously. The case is well-documented with clear medical records, test results, and imaging. The improvement after stopping the medication and adding supplements supports the diagnosis. More research with larger groups of patients is needed to confirm whether this is a common problem or a rare occurrence.

What the Results Show

The patient presented with severe weakness that made it impossible for him to walk. Physical examination showed significant weakness in both legs, especially in the feet and lower legs, along with loss of normal reflexes and decreased sensation. These symptoms developed gradually over three months after his stomach surgery and worsened when his semaglutide dose increased.

Blood tests revealed critically low levels of thiamine (vitamin B1) and vitamin E. These are essential nutrients that help nerves function properly. The patient’s spine imaging showed some mild inflammation of the nerve roots but no major blockages or structural damage that would explain his severe symptoms.

Once doctors stopped the semaglutide and started high-dose thiamine and vitamin E supplements, the patient’s condition improved. Within one month of hospitalization and physical therapy, his strength and sensation began returning to normal. This improvement strongly suggests the nerve damage was caused by the vitamin deficiencies rather than a structural spine problem.

The case highlights that the combination of weight loss surgery and semaglutide may create a ‘double hit’ to nutrient absorption. Weight loss surgery already reduces how much food people eat and can interfere with nutrient absorption. Semaglutide further reduces appetite and food intake. Together, these treatments may make it much harder for the body to get enough vitamins and minerals. The timing matters too—starting semaglutide soon after surgery may be particularly risky because the digestive system is still healing.

Thiamine deficiency is a known complication of weight loss surgery, and doctors have guidelines to screen for it. However, this case suggests that adding semaglutide to the mix may increase the risk significantly. Vitamin E deficiency is less commonly discussed in weight loss patients but can cause serious nerve damage. The combination of both deficiencies in one patient using both treatments is unusual and concerning. This case suggests that current monitoring guidelines for weight loss surgery patients may not be adequate when semaglutide is also being used.

This is only one patient’s story, so we cannot know how common this problem is. We don’t know if this would happen to most people using both treatments or if this patient had special risk factors. The case report doesn’t include information about the patient’s diet, whether he was taking supplements, or other health conditions that might have contributed. We don’t know what happens to other patients using semaglutide after weight loss surgery. Larger studies following many patients over time are needed to understand the real risks.

The Bottom Line

If you have had weight loss surgery and are considering semaglutide or similar medications, discuss this case with your doctor. Ask about getting blood tests to check your vitamin and mineral levels before starting the medication and regularly afterward. Make sure you’re taking recommended supplements after your surgery. If you’re already on both treatments, talk to your doctor about whether you need more frequent nutrient testing. Don’t stop semaglutide without medical guidance, but do report any new weakness, numbness, or difficulty walking immediately. (Confidence: This is based on one case, so recommendations are cautious.)

This is most important for people who have had weight loss surgery and are considering semaglutide or other GLP-1 medications. It’s also important for their doctors—including bariatric surgeons, weight loss specialists, primary care doctors, and dietitians. People considering weight loss surgery should know about this potential risk. People already taking semaglutide without surgery should be aware, though the risk appears lower. People with existing nerve problems or vitamin deficiencies should be especially cautious.

In this case, serious symptoms developed over three months. Improvement began within days of stopping the medication and starting supplements, with significant recovery over one month. However, nerve damage can sometimes take longer to fully heal. If you develop weakness or numbness, don’t wait—seek medical attention immediately.

Want to Apply This Research?

  • If using weight loss medications after surgery, track weekly: (1) any new weakness, numbness, or tingling in legs or feet, (2) ability to walk and climb stairs on a scale of 1-10, (3) dates of vitamin supplement doses taken, and (4) dates of medical appointments and lab work.
  • Set reminders to take all recommended vitamin supplements daily after weight loss surgery. If starting semaglutide, schedule a nutrition consultation and baseline blood work. Create a symptom log to share with your doctor at each visit. Set calendar alerts for regular follow-up appointments and lab tests.
  • Establish a baseline by getting blood tests for thiamine, vitamin E, and other key nutrients before starting semaglutide. Then schedule follow-up blood work every 3 months for the first year, then every 6 months. Track any new neurological symptoms in your app. Share your symptom log and supplement adherence data with your healthcare team at each visit. If symptoms develop, seek immediate medical attention rather than waiting for scheduled appointments.

This case report describes one patient’s experience and should not be interpreted as medical advice. If you are taking semaglutide, have had weight loss surgery, or are considering either treatment, consult with your healthcare provider before making any changes. Do not stop taking prescribed medications without medical guidance. Seek immediate medical attention if you experience new weakness, numbness, tingling, or difficulty walking. This information is educational and does not replace professional medical evaluation and treatment. Individual risks and benefits vary based on personal health factors that only your doctor can assess.