Feeling shaky on Mounjaro (tirzepatide) is a symptom that requires careful evaluation, as it may indicate hypoglycaemia or other medication-related effects. Mounjaro is a dual GIP and GLP-1 receptor agonist licensed in the UK for type 2 diabetes mellitus, and whilst it carries a lower intrinsic risk of low blood glucose compared to some antidiabetic agents, shakiness can occur—particularly when combined with sulphonylureas or insulin. Understanding the causes, recognising warning signs, and knowing when to seek medical advice are essential for safe and effective treatment. This article explores why shakiness occurs, how to manage it, and when professional review is needed.

Why Mounjaro Can Cause Shakiness

Mounjaro (tirzepatide) is a dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist licensed in the UK for the treatment of type 2 diabetes mellitus. Tirzepatide is also available under the brand name Zepbound for weight management in adults with obesity or overweight with weight-related comorbidities. The medication works by enhancing insulin secretion in a glucose-dependent manner, suppressing glucagon release, slowing gastric emptying, and reducing appetite. These mechanisms collectively improve glycaemic control and promote weight loss.

Shakiness whilst taking Mounjaro can arise through several pathways related to its pharmacological action. The most clinically significant cause is hypoglycaemia (low blood glucose), particularly when Mounjaro is used in combination with other glucose-lowering medications such as sulphonylureas or insulin. Although Mounjaro's glucose-dependent mechanism means it carries a lower intrinsic risk of hypoglycaemia compared to some other antidiabetic agents, the risk increases substantially when used alongside medications that independently cause hypoglycaemia.

Additionally, the gastrointestinal effects of Mounjaro—including nausea, vomiting, and reduced appetite—may affect nutritional intake. In some cases, particularly when combined with insulin or sulphonylureas, significantly reduced caloric consumption may contribute to lower blood glucose levels, potentially triggering symptoms such as tremor and shakiness. Alcohol consumption can also precipitate or worsen hypoglycaemia and shakiness.

Rapid weight loss can contribute to feelings of weakness and tremulousness, particularly during the initial titration phase when the body is adjusting to both the medication and changes in eating patterns. Understanding these mechanisms is essential for both patients and healthcare professionals to appropriately identify and manage shakiness during Mounjaro therapy.

Recognising Low Blood Sugar (Hypoglycaemia) on Mounjaro

Hypoglycaemia is formally defined as a blood glucose level below 4.0 mmol/L, though symptoms may occur at slightly higher levels in some individuals, particularly those with chronically elevated glucose levels. Recognising the signs and symptoms of hypoglycaemia is crucial for patient safety, as untreated episodes can progress to severe hypoglycaemia with loss of consciousness or seizures.

Common symptoms of hypoglycaemia include:

• Autonomic symptoms: Tremor or shakiness, sweating, palpitations, anxiety, and hunger

• Neuroglycopenic symptoms: Confusion, difficulty concentrating, visual disturbances, weakness, drowsiness, and behavioural changes

• General symptoms: Headache, dizziness, and nausea

Patients taking Mounjaro should be particularly vigilant if they are also prescribed sulphonylureas (such as gliclazide) or insulin, as the combination significantly increases hypoglycaemia risk. The MHRA and manufacturer guidance suggest considering dose reduction of these concomitant medications when initiating Mounjaro to mitigate this risk.

If you suspect hypoglycaemia, immediate management is essential. Check your blood glucose level if possible using a home glucose meter. If the reading is below 4.0 mmol/L, or if testing is unavailable but symptoms are present, follow the '15-15 rule': consume 15–20 grams of fast-acting carbohydrate (such as five glucose tablets, 150–200 ml of non-diet fruit juice, or four to five jelly babies), wait 15 minutes, then recheck your glucose. Avoid chocolate or fatty foods as these slow sugar absorption. If levels remain low or symptoms persist, repeat the treatment. Once blood glucose normalises, consume a longer-acting carbohydrate such as a slice of bread or a biscuit to maintain stability.

For severe hypoglycaemia where a person is unconscious or unable to swallow safely, glucagon (injection or nasal spray) may be needed. Family members or carers should be taught how to administer this emergency treatment.

Patients experiencing recurrent hypoglycaemic episodes should contact their GP or diabetes specialist nurse promptly for medication review and dose adjustment. Do not drive if you are experiencing hypoglycaemia symptoms or are at risk of hypoglycaemia, and follow DVLA guidance regarding diabetes and driving.

Other Causes of Shakiness While Taking Mounjaro

Whilst hypoglycaemia is the most concerning cause of shakiness in patients taking Mounjaro, several other factors may contribute to tremor or feelings of unsteadiness that are not directly related to low blood glucose levels.

Dehydration and electrolyte imbalance can occur secondary to the gastrointestinal adverse effects commonly associated with Mounjaro, particularly nausea, vomiting, and diarrhoea. These symptoms are most pronounced during the initial weeks of treatment and following dose escalation. Inadequate fluid intake combined with fluid losses can lead to dehydration, which may manifest as shakiness, dizziness, and weakness. Maintaining adequate hydration—aiming for approximately 2 litres of fluid daily unless otherwise advised—is important during Mounjaro therapy.

Anxiety and stress may also present with physical symptoms including tremor, particularly in patients adjusting to a new medication regimen or experiencing concerns about potential side effects. Anxiety is not listed as an adverse reaction in the UK product information for Mounjaro, but anxiety symptoms can include tremor regardless of the cause.

Caffeine consumption can exacerbate feelings of shakiness, especially if dietary changes have altered your usual eating patterns. On an empty stomach or with reduced food intake, the stimulant effects of caffeine may be more pronounced.

Rapid weight loss, whilst often therapeutically beneficial, can temporarily affect energy levels and cause sensations of weakness or tremulousness as the body adapts to a lower caloric intake and changes in metabolic rate. This is generally self-limiting but should be monitored to ensure weight loss remains within safe parameters (typically 0.5–1 kg per week is considered sustainable).

Other medical conditions that can cause tremor or shakiness include thyroid disease, anaemia, infections, heart rhythm disturbances, and effects of other medications. If shakiness persists despite normal blood glucose readings and adequate hydration, further medical evaluation is warranted, which may include blood tests to check electrolytes, full blood count, and thyroid function.

When to Seek Medical Advice for Shakiness

Understanding when shakiness requires urgent medical attention versus routine review is essential for patient safety. Seek immediate medical attention (call 999 or attend A&E) if you experience:

• Loss of consciousness or seizures

• Severe confusion or inability to self-treat hypoglycaemia

• Persistent hypoglycaemia despite appropriate treatment

• Chest pain, severe palpitations, or difficulty breathing accompanying shakiness

• Signs of severe dehydration (reduced urine output, extreme thirst, sunken eyes, rapid heartbeat)

Contact your GP or diabetes specialist nurse within 24 hours if:

• You experience recurrent episodes of shakiness or confirmed hypoglycaemia

• You have any severe hypoglycaemic episode requiring assistance from another person

• You experience hypoglycaemia without warning symptoms

• Shakiness is accompanied by persistent vomiting or diarrhoea lasting more than 24 hours

• You are unable to maintain adequate fluid or food intake due to gastrointestinal side effects

• Blood glucose readings are consistently below 4.0 mmol/L despite medication adjustments

• Shakiness is significantly impacting your daily activities or quality of life

Arrange a routine appointment (within 1–2 weeks) if:

• You experience mild, intermittent shakiness without confirmed hypoglycaemia

• You have concerns about your medication regimen or side effect management

• You require education on hypoglycaemia recognition and self-management

• You are experiencing unexplained weight loss exceeding 1 kg per week

If you're unsure about the urgency of your symptoms, contact NHS 111 for advice.

Patients should maintain a symptom diary documenting episodes of shakiness, associated blood glucose readings (if available), timing in relation to meals and medication doses, and any accompanying symptoms. This information is invaluable for healthcare professionals when reviewing your treatment plan and making appropriate adjustments.

Remember that you should not drive for at least 48 hours after a severe hypoglycaemic episode and should follow DVLA guidance regarding diabetes and driving safety. Regular monitoring and open communication with your diabetes care team are fundamental to safe and effective Mounjaro therapy.

Managing and Preventing Shakiness on Mounjaro

Effective management of shakiness whilst taking Mounjaro involves both immediate symptom relief and longer-term preventative strategies tailored to the underlying cause.

For hypoglycaemia prevention:

• Regular meal timing: Establish consistent meal patterns to maintain stable blood glucose levels. Avoid prolonged fasting periods, particularly if taking concomitant glucose-lowering medications.

• Balanced nutrition: Despite reduced appetite, ensure meals contain adequate complex carbohydrates, protein, and healthy fats to provide sustained energy release.

• Medication review: If you are taking sulphonylureas or insulin alongside Mounjaro, your prescriber may need to reduce doses of these medications. Never adjust doses independently without medical guidance.

• Blood glucose monitoring: If you have access to a glucose meter, regular monitoring (particularly before meals and when symptomatic) helps identify patterns and guide management.

• Carry fast-acting carbohydrates: Always have glucose tablets, fruit juice, or sweets readily available to treat hypoglycaemia promptly.

• Alcohol awareness: Avoid drinking alcohol on an empty stomach and moderate your intake, as alcohol can increase hypoglycaemia risk.

For gastrointestinal symptom management:

• Gradual dose titration: Follow the prescribed dose escalation schedule as outlined in your treatment plan. Slower titration may reduce gastrointestinal side effects.

• Smaller, frequent meals: Eating smaller portions more frequently can help manage nausea whilst maintaining adequate nutrition.

• Adequate hydration: Sip fluids regularly throughout the day. Oral rehydration solutions may be beneficial if experiencing vomiting or diarrhoea.

• Avoid trigger foods: Identify and temporarily avoid foods that exacerbate nausea (often fatty, spicy, or strongly flavoured foods).

General wellbeing strategies:

• Moderate caffeine intake: Limit caffeinated beverages, particularly on an empty stomach.

• Adequate rest: Ensure sufficient sleep, as fatigue can exacerbate feelings of shakiness and weakness.

• Gradual physical activity: While exercise is beneficial, avoid sudden increases in activity intensity that might precipitate hypoglycaemia.

• Sick-day rules: If you're unwell with vomiting or diarrhoea, maintain fluid intake and seek medical advice if unable to eat or drink for more than 24 hours.

NICE guidance (NG28) emphasises the importance of individualised diabetes management with regular review and adjustment based on patient response and tolerability. Your healthcare team can provide personalised advice, arrange diabetes education programmes, and ensure your treatment plan optimises both efficacy and safety.

If you experience any suspected side effects from Mounjaro, report them to the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk). Patient education regarding hypoglycaemia recognition, prevention, and self-management is a cornerstone of safe Mounjaro therapy and should be reinforced at each clinical contact.

Frequently Asked Questions