Can Mounjaro impact your energy levels?

Like Wegovy, Mounjaro has become a hugely popular weight loss treatment in recent years.

While it uses a different active ingredient (a medication known as tirzepatide, rather than semaglutide, which is found in Wegovy), it’s also delivered in pen form, with a pre-filled injectable that helps users lose weight over time. 

Mounjaro works by curbing your appetite and slowing gastric emptying (the process where food moves from your stomach to your small intestine), ideally reducing overall calorie intake.

If you’re already on Mounjaro, or you’re in the process of researching its potential for weight reduction, you might be curious whether it can affect your energy levels.

As it turns out, it can — but thankfully, there are ways to manage Mounjaro-induced fatigue. Here’s what you need to know.

Why does Mounjaro make you tired?

Like most medications, Mounjaro isn’t without its potential side effects.

Some of the most frequent include nausea, vomiting, indigestion, decreased appetite, constipation, diarrhoea, stomach discomfort, and injection site reactions like redness and irritation [1].

In rare cases, it can cause severe stomach pain and thyroid tumours, including thyroid cancer.

But that’s not to say they’re the only side effects of Mounjaro.

Tiredness or fatigue is a fairly common concern, even though it hasn’t officially been noted in Mounjaro’s clinical trials. (The medication is still fairly new, and studies are still ongoing on its side effects and long-term impacts.)

Experts aren’t entirely sure why Mounjaro causes fatigue, but there are a few solid theories. Some of the main ones include:

It’s a side effect of other side effects

If you’re experiencing a more common side effect like nausea, vomiting or diarrhoea, it’s entirely possible that fatigue could be a consequence of these.

For instance, if you’re vomiting a lot, you might become dehydrated, a condition that can make you feel incredibly low in energy.

You might have hypoglycemia

Hypoglycemia (low blood sugar) can make you feel tired.

On its own, Mounjaro doesn’t typically lead to low blood sugar, but if you have diabetes and you’re taking Mounjaro alongside other diabetes medications such as insulin or sulphonylurea, you have an increased risk of hypoglycemia [2].

You may not be eating much

The whole point of Mounjaro is to reduce your appetite, leading to fewer calories being consumed.

Calories provide your body with energy, so if you’re not getting as many of them, your metabolism may slow down to conserve energy. In turn, you might feel unusually tired.

Tirzepatide could be interacting with your cycles

The active ingredient in Mounjaro, tirzepatide, works by affecting your hypothalamus — the part of the brain that controls hunger and appetite.

But the hypothalamus also has another very important role: regulating your sleep-wake cycle.

Given its impact on the hypothalamus, it’s entirely possible that taking Mounjaro could disrupt your usual sleep patterns and make you feel tired.

How long can Mounjaro fatigue last?

The length of time Mounjaro fatigue lasts varies from person to person.

For some, it can stick around for 1 or 2 days after each injection, others have ongoing tiredness for weeks and others still never experience it at all.

This is because several factors influence its duration, including overall health, sleep patterns, age, diet, activity levels, and hydration.

That being said, tiredness is typically only temporary and improves as your body adjusts to the medication. (You’ll be glad to know that other side effects like nausea and vomiting are often short-lived too!)

However, if you notice the fatigue lingering beyond 4 or so weeks, reach out to your doc for advice.

Your dose might be too high or there may be another underlying cause or condition causing exhaustion.

How to manage Mounjaro fatigue

So, how can you manage the fatigue? The ideas below aren’t totally foolproof, and you may still experience some tiredness while taking the medication, but they could help to minimise it.

Get enough sleep

It probably goes without saying that if you’re not getting enough shut-eye, your fatigue is likely to be worse. 

Try to get to bed at the same time each night and aim for 7-9 hours of sleep (the amount recommended for adults) [3].

Adequate sleep also offers a bunch of physical and mental health benefits like reduced risk of chronic diseases such as type 2 diabetes and stroke; improved heart health; better mood and cognitive function; and even a higher chance of maintaining a healthy weight [4].

Create a sleep-friendly environment

Ensure your bedroom is conducive to rest to encourage a decent night’s sleep. This means:

• Reducing brightness, perhaps with blackout curtains or blinds, especially before bed
• Keeping your room cool and using breathable bedding made from cotton, linen or bamboo
• Maintaining good airflow in the room
• Minimising noise, either with a white noise machine or earplugs
• Implementing a quiet wind-down routine about an hour before bed — reading a book or meditating can help.

Limit your caffeine intake

While we’re not necessarily telling you to give up coffee, it could be worth limiting your caffeine intake.

Caffeine is a stimulant that temporarily makes you feel more alert and energetic, and consuming too much of it or having it late in the day can disrupt your ability to fall asleep. 

Experts recommend sticking to a maximum of 400mg of caffeine each day, ideally spread across the day to prevent energy crashes, and avoided after midday [5].

For reference, there are about 96mg of caffeine in a cup of brewed coffee, 64mg in a single shot of espresso, 62mg in a cup of instant coffee, 47mg in a cup of black tea, 28mg in a cup of green tea, and 22mg in a can of cola.

And your light exposure

Blue light is emitted from screens like your phone, tablet, and telly.

It can be problematic because it interferes with the production of melatonin, the hormone that makes you sleepy and keeps your sleep cycles in check.

Your body produces melatonin when it’s dark to prepare you for sleep. But if it’s exposed to too much blue light, melatonin production decreases and it can make it more difficult to fall asleep.

Your best bet is to avoid screens for about an hour before bedtime.

Consume enough protein

Protein is a great macronutrient to include in your diet because it builds muscle, makes you feel fuller for longer, and may help combat Mounjaro fatigue.

This is due to protein’s ability to provide a steady release of energy and avoid blood sugar swings that can contribute to lethargy.

Several factors determine how much protein you need, like your age, activity levels and body weight. However, if you want to lose weight, a popular guideline is to aim for 30g of protein with each meal.

Maintain a balanced diet

Try to limit your intake of certain foods and drinks that can cause energy fluctuations, like those that are high in sugar.

Prioritise complex carbs such as oats and whole grains, alongside plenty of fresh fruit and veg and healthy fats.

Big portions and skipping meals can also lead to energy swings. Instead, smaller meals and snacks across the day can keep your energy levels consistent.

They deliver a steady dose of calories, stabilising your blood sugar and preventing energy spikes (and the inevitable crash).

Stay hydrated

Hydration is key to good health because it supports cell function, healthy digestion,  and even body temperature. It may also help you deal with Mounjaro tiredness, as it can bolster your energy levels. 

The NHS recommends aiming for 6-8 glasses of fluids each day to stay hydrated [6]. This can include water, tea, coffee, low-fat milk, and low or no-sugar drinks.

Just make sure to up your intake if you’re exercising a lot, as working out makes you lose fluids.

Move more

Exercise may already be a part of your weight loss regimen, but here's another good reason to move your body: it can sustain your energy levels.

It boosts blood flow to deliver oxygen and nutrients to your muscles and tissues, plus it improves your cardiovascular health. 

Exercise also makes your muscles work better, which can mean that certain activities don’t leave you feeling as depleted.

There are lots of exercises that can boost your energy levels, including moderate-intensity cardio (such as cycling, jogging, dancing, or brisk walking), resistance training (including bodyweight exercises and weight-lifting), and even stretching and yoga.

Schedule some rest time

Even after implementing these tips, you may still notice feelings of fatigue on Mounjaro. 

If you can, give yourself regular rest time whenever tiredness strikes. Enjoy a quiet day at home, take part in restorative activities like yoga, reading and meditation, or simply remain horizontal on the sofa.

Chat to your doc

If the lethargy is becoming unbearable or you’re not noticing an improvement over time, make an appointment with your doctor.

They can assess whether there’s something else going on with your health and help you find other ways to manage the fatigue.

You should also seek immediate medical attention if you experience a severe allergic reaction or other serious side effects like low blood sugar, kidney or gallbladder problems, thyroid issues, pancreatitis (inflammation of the pancreas), severe abdominal pain, or changes to your vision.

Lose weight the sustainable way with Juniper

Looking to lose weight? With Juniper's Weight Reset Programme, you get weight loss advice at your fingertips and unlimited consultations with a healthcare provider, so you can use Mounjaro with confidence and ease.

On top of the weight loss drugs, you get access to unlimited support from our expert dietitians, a strength and cardio exercise plan to help you maintain muscle mass as you lose weight, tracking tools to keep you motivated, and access to a private community of women on the same journey as you.

Designed by UK clinicians, this programme gives you the tools you need to make informed decisions, so you can not only lose weight but keep it off well into the future.