Although insomnia and sleep disturbance are not listed as common side effects in official prescribing information for Mounjaro [3], some patients report changes to their sleep after starting treatment. These range from difficulty falling asleep to vivid dreams or restless nights.

This article explores what’s known from clinical evidence, the possible biological mechanisms, and practical strategies you can use if your sleep is affected.

What is Mounjaro?

Mounjaro is a once-weekly injectable treatment containing tirzepatide, a dual agonist of two naturally occurring gut hormones:

• GLP-1 (glucagon-like peptide-1)‍
• GIP (glucose-dependent insulinotropic polypeptide)
  

These hormones regulate blood sugar, slow gastric emptying, and reduce appetite. In large-scale trials (SURPASS and SURMOUNT programmes), tirzepatide helped patients with type 2 diabetes and obesity achieve significant weight loss while improving glycaemic control [5], [6].

Like all medications, Mounjaro can cause side effects, but its benefits in metabolic health are well established.

Is insomnia a recognised side effect?

In phase 3 clinical trials, the most common side effects were gastrointestinal — nausea, diarrhoea, constipation, vomiting, and decreased appetite (FDA, 2022). Sleep disturbance was not reported as a frequent adverse event.

However, post-marketing reports and patient anecdotes suggest some individuals notice:

• Trouble falling asleep
  
• Waking multiple times during the night
  
• Light or restless sleep
  
• Vivid or unusual dreams
  
• Early waking and feeling unrefreshed
  

For many, these changes are temporary, improving as the body adapts to treatment.

3. Why might Mounjaro affect sleep?

Although no trial has shown a direct causal link between Mounjaro and insomnia, several plausible indirect mechanisms exist:

a) Gastrointestinal discomfort

Common side effects like nausea, bloating, or reflux can make it harder to fall asleep — particularly if they peak in the evening or on injection day [4].

b) Blood glucose fluctuations

Tirzepatide improves insulin sensitivity and reduces appetite. Lower caloric intake can lead to lower nocturnal glucose levels in some people, potentially triggering restlessness or early waking [2].

c) Hormonal changes from weight loss

Rapid or significant weight loss can alter leptin, ghrelin, and cortisol levels — all hormones that influence appetite and sleep–wake cycles [7].

d) Changes in daily routine

Appetite suppression may shift mealtime patterns. Eating much earlier than usual, or skipping dinner, can affect circadian rhythm and sleep quality.

e) Psychological adjustment

Starting a potent new medication for weight loss can bring heightened anticipation or anxiety, which may temporarily affect sleep onset or depth.

What does the research say?

Currently, there are no dedicated studies on Mounjaro and sleep outcomes. However, indirect evidence from GLP-1 receptor agonist research offers clues:

• A 2023 review suggested that while GLP-1 drugs are not classed as sleep medicines, their effects on metabolic and hormonal pathways could influence sleep regulation [9].
  
• Weight loss interventions, including pharmacological ones, have been linked to improvements in obstructive sleep apnoea severity, but transitional sleep disturbance during active weight loss has been observed [1].
  

5. Patient experiences

While not clinical evidence, patient reports highlight some common themes:

“The first two weeks on Mounjaro, I was awake at 3am every night. Now I sleep through and feel better rested.”

“My dreams have been wild since I started. I think it’s because my dinners are smaller now.”

“I had reflux at night after injection day, so I switched to morning injections  it helped.”

Practical strategies for better sleep on Mounjaro

If your sleep has changed since starting Mounjaro, these strategies may help:

• Change injection timing – Try injecting earlier in the day to reduce evening nausea or reflux.
  
• Optimise your evening meal – Have a light, balanced dinner with protein, fibre, and complex carbs 2–3 hours before bed.
  
• Support stable blood sugar – A small pre-bed snack (e.g. Greek yoghurt with berries) can prevent early waking from hunger. Some supplements, such as our Fibre Complex, can also support long-term blood sugar control.
  
• Maintain consistent sleep hygiene – Go to bed and wake up at the same times each day. Reduce screen time before bed.
  
• Create a wind-down routine – Reading, stretching, or meditation can help prepare your body for sleep. A daily sleep supplement, like Habitual's Deep Sleep Complex, can also be a nice addition to your bedtime routine.
  
• Stay hydrated — strategically – Drink enough during the day, but reduce intake close to bedtime to avoid nocturnal bathroom trips.
  
• Manage reflux or bloating – Avoid lying down immediately after eating; elevate your upper body slightly if reflux is a problem.
  
• Track patterns – Keep a diary of injection days, mealtimes, and symptoms to share with your clinician.
  

When to seek medical advice

Contact your healthcare provider if you experience:

• Persistent insomnia lasting more than a few weeks
  
• Severe or worsening night-time nausea
  
• Signs of low blood sugar (shakiness, sweating, confusion)
  
• Mood changes or heightened anxiety
  
• Ongoing reflux or abdominal pain
  

Your prescriber may adjust your dose, injection day, or suggest supportive measures.

The role of sleep in weight loss

Good sleep isn’t just about rest, it supports the very goals Mounjaro is designed to achieve:

• Poor sleep raises ghrelin and lowers leptin, increasing hunger [7].
  
• Sleep restriction reduces insulin sensitivity [8].
  
• Sleep deprivation increases cortisol, which can hinder fat loss.
  

Protecting your sleep is therefore a crucial part of sustaining your progress on Mounjaro.

Final thoughts

Mounjaro isn’t officially recognised as a cause of sleep disturbance, but anecdotal evidence shows some people experience temporary changes. These are often manageable with simple adjustments to timing, diet, and bedtime routine.

If disrupted sleep is affecting your quality of life, speak to your healthcare provider, with the right approach, you can enjoy both the metabolic benefits of Mounjaro and the restorative power of a good night’s sleep.

‍