Starting a weight loss injection can raise plenty of questions, and one we hear regularly is whether Mounjaro causes fatigue. If you have been researching your options and wondering how tiredness compares across different treatments, you are not alone. Understanding what to expect from each medication can help you feel more prepared before beginning your journey.
Weight loss injections work in different ways, and their side effect profiles can vary. Fatigue is reported with several of these treatments, though how commonly it occurs and how it presents can differ depending on the medication.
If you would like to explore which weight loss treatment may be suitable for you, contact us or book a consultation with the team at Mendus Pharmacy in Pembroke.
Does Mounjaro Make You Tired?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, meaning it targets two hormones involved in appetite and blood sugar regulation. Fatigue is listed as a recognised side effect, and some people do report feeling more tired, particularly during the early weeks of treatment or following a dose increase.
The tiredness associated with Mounjaro is often thought to be connected to reduced calorie intake, as the body adjusts to consuming less food. Nausea, which is also common, can contribute to low energy levels.Common side effects of tirzepatide include nausea, diarrhoea, vomiting, and decreased appetite, all of which can indirectly contribute to feelings of fatigue.
For most people, fatigue tends to settle as the body adjusts to the medication. However, if tiredness is persistent or severe, it is important to speak with a healthcare professional.
How Does Fatigue Compare Across Weight Loss Treatments?
Fatigue is not unique to Mounjaro. Several weight loss medications list tiredness or low energy among their possible side effects. Below is a comparison of five commonly used treatments and how tiredness features within their side effect profiles.
| Medication | Active Ingredient | How It Works | Fatigue Reported? | Other Common Side Effects |
|---|---|---|---|---|
| Mounjaro | Tirzepatide | Dual GIP and GLP-1 receptor agonist | Yes, particularly early in treatment | Nausea, diarrhoea, vomiting, reduced appetite |
| Wegovy | Semaglutide | GLP-1 receptor agonist | Yes, reported by some users | Nausea, constipation, headache, dizziness |
| Saxenda | Liraglutide | GLP-1 receptor agonist | Yes, fatigue is a listed side effect | Nausea, vomiting, diarrhoea, headache |
| Mysimba | Naltrexone and bupropion | Acts on appetite and reward pathways in the brain | Yes, fatigue and sleep disturbance reported | Nausea, headache, dizziness, insomnia |
| Xenical | Orlistat | Lipase inhibitor, reduces fat absorption | Less commonly reported | Oily stools, frequent bowel movements, stomach cramps |
As shown above, fatigue appears across the majority of these medications, though the mechanism and frequency can differ. Xenical tends to be associated with digestive side effects rather than energy-related ones, whereas the injectable GLP-1 treatments are more frequently linked with tiredness, particularly during dose escalation periods.
Why Do These Medications Cause Tiredness?
There are several reasons why weight loss medications may contribute to fatigue:
- Reduced calorie intake caused by appetite suppression can lower energy levels
- Nausea and gastrointestinal discomfort can be physically draining
- The body requires time to adjust to changes in hormone signalling
- Blood sugar fluctuations, particularly in early treatment, may affect energy
- Disrupted sleep, which is reported with some medications such as Mysimba, can contribute to daytime tiredness
Understanding why tiredness occurs can make it easier to manage during the adjustment period. Staying well hydrated, eating balanced meals within your recommended intake, and maintaining a regular sleep routine may all help.
Tips for Managing Fatigue During Weight Loss Treatment
Click on each tip to uncover ways to ease side effects of Mounjaro.
Stay hydrated throughout the day
Dehydration can worsen fatigue. Aim to drink enough water throughout the day, particularly if you are experiencing nausea or gastrointestinal symptoms that may affect fluid intake. If you have increased exercise to support your medication journey, it is even more important to stay hydrated.
Eat regular, balanced meals
Even with a reduced appetite, it is important to eat nutritious meals that support your energy levels. Focus on protein, wholegrains, and vegetables to maintain steady energy throughout the day.
Allow time for adjustment
Many side effects, including tiredness, tend to ease as your body adjusts to the medication. This is particularly true following dose increases, where a short period of fatigue may be expected before settling.
Speak to a healthcare professional if symptoms persist
If fatigue is ongoing, severe, or affecting your daily life, it is important to seek professional advice rather than continuing without support. There may be adjustments that can help.
Frequently Asked Questions
Does Mounjaro make you more tired than Wegovy?
Both medications list fatigue as a possible side effect. Individual experiences vary, and tiredness linked to both Mounjaro and Wegovy is often related to reduced appetite and the body’s adjustment to treatment rather than a direct effect of the drug itself.
How long does fatigue last on Mounjaro?
For most people, tiredness is more noticeable during the first few weeks or following a dose increase. It often improves as the body adjusts. If it continues beyond this point, speaking with a clinician is advisable.
Is Xenical less likely to cause tiredness?
Xenical (orlistat) works differently to injectable treatments and is not commonly associated with fatigue in the same way. Its primary side effects relate to digestion and fat absorption. That said, any significant dietary change can affect energy levels.
Can Mysimba affect sleep as well as cause tiredness?
Yes. Mysimba contains bupropion, which can affect sleep patterns in some people. Insomnia and sleep disturbance are listed among its possible side effects, which may in turn contribute to daytime fatigue.
Should I stop taking my medication if I feel tired?
You should not stop taking prescribed medication without speaking to a healthcare professional first. If fatigue is a concern, seek advice so that your treatment can be reviewed appropriately.
A Note Before You Read On
This blog is intended as a general guide only and does not constitute medical advice. Side effects vary between individuals, and suitability for any weight loss treatment should be assessed by a qualified healthcare professional. Please contact us or visit us in Pembroke for personalised advice.
Speak to Our Team in Pembroke
Choosing a weight loss treatment is a personal decision, and understanding how each option may affect you is an important part of that process. Fatigue is a recognised side effect across several treatments, but it is manageable for most people and often improves over time.
Our team in Pembroke is here to help you explore your options and find an approach that works for you. Whether you have questions about Mounjaro, Wegovy, Saxenda, or any other treatment, we are happy to help.
Reach out to us today or book a consultation with Mendus Pharmacy to get started.