GLP-1 receptor agonists are widely prescribed in the UK for type 2 diabetes and weight management. Dizziness is a recognised side effect of these medications, though its frequency varies between products. This symptom may arise through several mechanisms, including low blood glucose (hypoglycaemia), dehydration from gastrointestinal effects, orthostatic hypotension, or reduced caloric intake. Understanding why dizziness occurs, how to manage it effectively, and when to seek medical advice is essential for patients taking GLP-1 medications. This article provides evidence-based guidance aligned with UK clinical practice, MHRA safety information, and NICE recommendations.

Can GLP-1 Medications Cause Dizziness?

Glucagon-like peptide-1 (GLP-1) receptor agonists are increasingly prescribed medications for type 2 diabetes and weight management in the UK. Dizziness is a recognised adverse reaction in the Summary of Product Characteristics (SmPCs) for several GLP-1 medications, though the frequency varies between different products.

Dizziness may occur through both direct and indirect mechanisms. GLP-1 agonists work by mimicking the action of the naturally occurring GLP-1 hormone, which stimulates insulin secretion in a glucose-dependent manner, suppresses glucagon release, slows gastric emptying, and reduces appetite. These effects can sometimes lead to symptoms of dizziness.

Several factors may contribute to dizziness in patients taking GLP-1 medications:

• Hypoglycaemia (low blood glucose) – particularly when GLP-1 agonists are used alongside other glucose-lowering medications such as sulphonylureas or insulin

• Dehydration – resulting from reduced fluid intake due to decreased appetite or from gastrointestinal side effects such as nausea, vomiting, or diarrhoea

• Orthostatic hypotension – a drop in blood pressure upon standing, which may occur due to volume depletion or rapid weight loss

• Reduced caloric intake – significant appetite suppression may lead to inadequate nutrition, potentially causing weakness and dizziness

The frequency and severity of dizziness vary between individuals and specific GLP-1 products. If you experience persistent or concerning dizziness, it's important to discuss this with your healthcare provider. The MHRA's Yellow Card scheme (yellowcard.mhra.gov.uk) allows patients and healthcare professionals to report suspected side effects, helping to build a comprehensive safety profile for these medications.

Managing Dizziness While Taking GLP-1 Medications

If you experience dizziness whilst taking a GLP-1 medication, several practical strategies can help manage this symptom and improve your overall treatment experience. These approaches address the most common underlying causes of dizziness in this context.

Maintaining adequate hydration is important. The gastrointestinal side effects commonly associated with GLP-1 agonists—including nausea, vomiting, and diarrhoea—can lead to fluid depletion. Aim to drink enough fluids throughout the day to keep your urine pale yellow. Small, frequent sips may be better tolerated than large volumes at once, particularly if nausea is present. If you have heart failure or kidney disease, follow your healthcare provider's specific guidance on fluid intake.

Monitoring blood glucose levels is essential if you're taking GLP-1 medications with insulin or sulphonylureas, or if you're experiencing symptoms of hypoglycaemia. Keep a record of your readings and note any episodes of dizziness. If your blood glucose falls below 4.0 mmol/L, treat immediately with 15–20g of fast-acting carbohydrate (such as glucose tablets, fruit juice, or sugary sweets), then recheck after 15 minutes, following NHS guidance on treating hypoglycaemia. Your GP or diabetes specialist nurse may need to adjust the doses of your other medications to reduce hypoglycaemia risk.

Nutritional adequacy should not be compromised despite reduced appetite. Focus on:

• Small, frequent meals rather than three large meals

• Nutrient-dense foods to ensure adequate vitamin and mineral intake

• Adequate protein to preserve muscle mass during weight loss

• Complex carbohydrates to maintain stable blood glucose levels

Managing orthostatic hypotension involves rising slowly from sitting or lying positions, allowing your cardiovascular system time to adjust. If dizziness persists, discuss with your healthcare provider before considering compression stockings or adjusting any blood pressure medications. Importantly, never reduce or stop insulin abruptly when starting GLP-1 therapy, as this carries a risk of diabetic ketoacidosis; any insulin adjustments must be clinician-led.

When to Seek Medical Advice About Dizziness

Whilst mild, transient dizziness may resolve with simple management strategies, certain symptoms warrant prompt medical attention. Understanding when to contact your GP or seek emergency care is crucial for patient safety.

Contact your GP or diabetes specialist nurse within 24–48 hours if you experience:

• Persistent dizziness that does not improve with hydration and dietary adjustments

• Recurrent episodes of dizziness, particularly if they interfere with daily activities

• Dizziness accompanied by frequent hypoglycaemia (blood glucose below 4.0 mmol/L on multiple occasions)

• Unexpected, very rapid, or concerning weight loss, or if you're unable to maintain adequate food intake

• Inability to maintain adequate fluid intake due to gastrointestinal side effects

• Dizziness associated with palpitations or irregular heartbeat

Seek immediate medical attention (call 999 or attend A&E) if you experience:

• Severe dizziness with loss of consciousness or near-fainting episodes

• Chest pain, shortness of breath, or severe palpitations accompanying dizziness

• Severe, persistent vomiting or diarrhoea leading to signs of dehydration (dark urine, dry mouth, confusion)

• Neurological symptoms such as slurred speech, visual disturbances, weakness, or severe headache—these may indicate conditions unrelated to your GLP-1 medication that require urgent assessment

• Severe abdominal pain, particularly if radiating to the back, which could indicate pancreatitis (a rare but serious adverse effect of GLP-1 agonists) – if you suspect pancreatitis, withhold your GLP-1 medication pending medical assessment

• Right upper abdominal pain with fever or yellowing of the skin/eyes, which could indicate gallbladder disease

Your healthcare provider will conduct a thorough assessment, which may include checking your blood pressure (both lying and standing), reviewing your blood glucose records, assessing your hydration status, and potentially ordering blood tests to evaluate kidney function and electrolyte balance. They may adjust your GLP-1 dose, modify other medications, or, in rare cases, consider discontinuing the GLP-1 agonist if the benefits no longer outweigh the risks.

Other Side Effects of GLP-1 Agonists to Monitor

Beyond dizziness, GLP-1 receptor agonists are associated with a range of side effects, most of which are mild to moderate and tend to diminish over time. Understanding these potential adverse effects enables patients to recognise them early and seek appropriate management.

Gastrointestinal side effects are the most commonly reported and include:

• Nausea (affecting 10–40% of patients, depending on the specific GLP-1 agonist)

• Vomiting and diarrhoea (less common than nausea but can contribute to dehydration)

• Constipation (due to slowed gastric emptying)

• Abdominal discomfort or bloating

These effects are typically most pronounced during treatment initiation and following dose increases. The gradual dose titration recommended in product SmPCs helps minimise gastrointestinal intolerance.

Injection site reactions may occur with subcutaneous GLP-1 formulations, presenting as redness, itching, or mild swelling at the injection site. Rotating injection sites and ensuring proper injection technique can reduce these reactions.

Hypoglycaemia risk is generally low with GLP-1 agonists when used as monotherapy, as their glucose-lowering effect is glucose-dependent. However, the risk increases significantly when combined with sulphonylureas or insulin, as noted in NICE guidance (NG28).

Rare but serious adverse effects require vigilance:

• Acute pancreatitis – presents with severe, persistent abdominal pain, often radiating to the back, accompanied by nausea and vomiting. This requires immediate medical assessment and discontinuation of the GLP-1 agonist.

• Gallbladder disease – rapid weight loss may increase the risk of gallstones, presenting as right upper quadrant abdominal pain, sometimes with fever or jaundice.

• Diabetic retinopathy complications – particularly noted with semaglutide, especially in patients with pre-existing retinopathy and those on insulin. Ensure your diabetic eye screening is up to date and report any new visual symptoms promptly.

• Acute kidney injury – typically associated with severe dehydration from gastrointestinal side effects; maintaining hydration is crucial.

Regular monitoring and open communication with your healthcare team are essential for optimising the benefits of GLP-1 therapy whilst minimising adverse effects. Report any suspected side effects to your healthcare provider and consider reporting them through the MHRA's Yellow Card scheme (yellowcard.mhra.gov.uk), including during pregnancy or breastfeeding.

Frequently Asked Questions