Does Mounjaro have caffeine? No, Mounjaro (tirzepatide) contains no caffeine or stimulant compounds. This prescription-only injectable medication is used to treat type 2 diabetes mellitus in adults and works through a unique dual-hormone mechanism. Some patients report increased energy after starting Mounjaro, but this relates to improved blood glucose control and weight management rather than stimulant effects. If you experience jitteriness or unusual alertness, discuss this with your healthcare provider, as these symptoms are not due to caffeine content. Patients can continue consuming tea or coffee as usual whilst taking Mounjaro, though moderation and avoiding high-sugar caffeinated drinks is advisable for optimal diabetes management.

Does Mounjaro Contain Caffeine?

No, Mounjaro does not contain caffeine. This is a common question among patients starting this medication, particularly those who may be sensitive to stimulants or monitoring their caffeine intake for other health reasons. Mounjaro (tirzepatide) is a prescription-only injectable medication used for the treatment of type 2 diabetes mellitus in adults, and it contains no caffeine or other stimulant compounds.

Some people report increased energy levels or changes in their usual patterns after starting Mounjaro. However, these effects may be related to improved blood glucose control and weight management rather than any stimulant properties. As blood sugar levels stabilise and if weight reduces, some individuals may feel more energetic.

If you experience symptoms such as jitteriness, rapid heartbeat, or unusual alertness after starting Mounjaro, these are not due to caffeine content and should be discussed with your healthcare provider, as they may indicate other effects of the medication or an unrelated condition.

Patients taking Mounjaro can continue to consume caffeine-containing beverages such as tea or coffee according to their usual habits, though moderation is always advisable. Be cautious with high-sugar caffeinated drinks like energy drinks or sweetened coffee, as these may affect your blood glucose control. No interaction between Mounjaro and caffeine is listed in the UK product information, but as with all aspects of diabetes management, discussing your diet with your healthcare team is recommended.

What Are the Active Ingredients in Mounjaro?

The sole active pharmaceutical ingredient in Mounjaro is tirzepatide, a synthetic peptide that mimics the action of two naturally occurring hormones in the body: glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). This dual-action mechanism makes Mounjaro unique among currently available diabetes medications, as it is the first approved dual GIP/GLP-1 receptor agonist.

Tirzepatide works by binding to and activating both GIP and GLP-1 receptors, which are found throughout the body, particularly in the pancreas, gastrointestinal tract, and brain. When blood glucose levels are elevated, tirzepatide stimulates the pancreas to release insulin whilst simultaneously suppressing the release of glucagon, a hormone that raises blood sugar. This glucose-dependent action means the medication primarily works when blood sugar is high, reducing the risk of hypoglycaemia (dangerously low blood sugar) compared to some other diabetes treatments.

Additionally, tirzepatide slows gastric emptying, meaning food moves more slowly from the stomach into the small intestine. This contributes to increased feelings of fullness and satiety, which can support weight management—an important consideration for many people with type 2 diabetes. The medication also appears to have direct effects on appetite regulation centres in the brain.

Mounjaro is available in pre-filled injection pens containing 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, or 15 mg of tirzepatide per dose. Treatment typically starts with 2.5 mg once weekly for 4 weeks, then increases in 2.5 mg steps as tolerated. The solution also contains inactive ingredients (excipients) to maintain the stability and pH of the solution. For a complete list of excipients, refer to the Patient Information Leaflet.

The medication is administered once weekly via subcutaneous injection into the abdomen, thigh, or upper arm. You should rotate injection sites each week to reduce the risk of skin reactions, and try to administer on the same day each week. If you miss a dose, take it within 4 days of the scheduled time; if more than 4 days have passed, skip that dose and take the next one at the regular scheduled time.

Common Side Effects of Mounjaro

Like all medications, Mounjaro can cause side effects, although not everyone experiences them. The most frequently reported adverse effects are gastrointestinal in nature, which is consistent with the medication's mechanism of action on the digestive system. Understanding these potential effects can help you manage them effectively and know when to seek medical advice.

Common gastrointestinal side effects include:

• Nausea – often most pronounced when starting treatment or increasing the dose, typically improving over time

• Diarrhoea – may occur intermittently, particularly in the first few weeks

• Vomiting – less common than nausea but can occur, especially if doses are increased too rapidly

• Constipation – some patients experience this rather than diarrhoea

• Abdominal pain or discomfort – usually mild to moderate

• Decreased appetite – whilst this contributes to weight loss, some patients find it excessive

• Indigestion or dyspepsia

These gastrointestinal effects are generally mild to moderate in severity and tend to diminish as your body adjusts to the medication. Eating smaller, more frequent meals, avoiding fatty or spicy foods, and staying well-hydrated may help reduce these symptoms.

Other reported side effects include:

• Injection site reactions (redness, itching, or swelling)

• Fatigue or tiredness

• Headache

• Dizziness

• Small increases in heart rate (seek advice if you experience persistent palpitations)

More serious but less common side effects warrant immediate medical attention. These include severe abdominal pain that doesn't resolve (which could indicate pancreatitis), persistent vomiting or diarrhoea leading to dehydration (which can affect kidney function), changes in vision (rapid improvement in blood glucose can temporarily worsen diabetic retinopathy), or signs of allergic reaction such as rash, swelling of the face or throat, or difficulty breathing. Hypoglycaemia is uncommon with Mounjaro alone but can occur if you're also taking other diabetes medications such as insulin or sulphonylureas.

You can report any suspected side effects to the MHRA Yellow Card Scheme at www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.

When to Speak with Your GP About Mounjaro

Regular communication with your GP or diabetes care team is essential when taking Mounjaro to ensure the medication is working effectively and safely. NICE guidance recommends ongoing monitoring of patients prescribed GLP-1 receptor agonists, including assessment of glycaemic control, weight, and tolerability.

You should contact your GP or healthcare provider if you experience:

• Severe or persistent gastrointestinal symptoms that don't improve after the first few weeks, particularly if they're affecting your nutrition or hydration

• Signs of pancreatitis – severe abdominal pain that may radiate to your back, often accompanied by nausea and vomiting

• Symptoms of hypoglycaemia – shakiness, sweating, confusion, rapid heartbeat, or extreme hunger, especially if you're taking other diabetes medications

• Persistent vomiting or diarrhoea that could lead to dehydration and kidney problems

• Changes in vision or eye problems, as rapid improvement in blood glucose can temporarily worsen diabetic retinopathy

• Symptoms of thyroid problems – a lump or swelling in your neck, hoarseness, difficulty swallowing, or shortness of breath (thyroid tumours have been observed in animal studies, though the relevance to humans is unknown)

• Signs of gallbladder problems – pain in the upper right abdomen, fever, yellowing of skin or eyes

• Allergic reactions – rash, itching, swelling, or difficulty breathing

Routine follow-up appointments are important to monitor your HbA1c levels (a measure of long-term blood glucose control), assess weight changes, and review your overall diabetes management plan. According to NICE guidance, if adequate glycaemic control isn't achieved or maintained with Mounjaro, or if the medication isn't tolerated, alternative treatment options should be considered.

You should also discuss with your GP if you're planning pregnancy, as Mounjaro is not recommended during pregnancy and should be discontinued at least one month before attempting to conceive. Effective contraception is advised while taking this medication. Similarly, inform your healthcare provider about all other medications you're taking, as dose adjustments may be needed, particularly for insulin or sulphonylureas, to reduce the risk of hypoglycaemia. Never stop taking Mounjaro without consulting your healthcare provider, as abrupt discontinuation may lead to worsening blood glucose control.

Frequently Asked Questions