When it comes to GLP-1 medications like Mounjaro and Zepbound (tirzepatide), side effects like nausea and diarrhea usually get the most attention. But another common (and often overlooked) symptom is fatigue.

If you’re feeling more sluggish since starting tirzepatide, you’re not alone. Here’s why fatigue can happen, and what you can do to regain your energy while staying on track with your treatment.

Does Tirzepatide Cause Fatigue?

Yes, fatigue can be a side effect of tirzepatide—especially with Zepbound.

In clinical trials:

• 7% of people taking 15 mg reported fatigue
• 6% on 10 mg reported fatigue
• 5% on 5 mg reported fatigue
• Compared to just 3% on placebo

Although fatigue isn’t officially listed as a common side effect for Mounjaro, many patients report feeling unusually tired. Social media conversations and exit interviews from clinical trials also show that fatigue and sleep disturbances are frequently mentioned by people taking GLP-1medications in general (including tirzepatide, semaglutide, and others).

What fatigue feels like on tirzepatide: It’s often described as low-level exhaustion, sluggishness, or a lack of energy—distinct from regular tiredness.

Why Does Tirzepatide Make You Tired?

There are a few reasons why fatigue can happen:

1. Reduced calorie intake

Tirzepatide dramatically suppresses appetite. Research shows people consume almost 200 fewer calories per meal within the first eight weeks of treatment.Less food = less energy for your body to function.

2. Hormonal shifts

The way tirzepatide alters hormone signaling can reduce both appetite and available energy, explains Arthur Shektman, MD.If you're sensitive to blood sugar changes or dehydration, you may feel like you're "hitting a wall."

3. Dehydration and electrolyte imbalances

Tirzepatide can cause side effects like nausea, vomiting, and diarrhea—leading to fluid and electrolyte loss.Even without these symptoms, appetite suppression can cause people to forget to drink enough water, raising dehydration risk.

How to Manage Fatigue While Taking Tirzepatide

If you're feeling wiped out, here are practical strategies to boost your energy:

1. Stay Hydrated

Dehydration is a top cause of fatigue. Drink plenty of fluids throughout the day—even if you're not thirsty—and consider electrolyte enhanced drinks if you’re dealing with nausea, vomiting, or diarrhea.

Tip: Keep a water bottle with you and sip regularly.

2. Exercise Regularly

Physical activity is a proven energy booster. Start small:

• 20 minutes of low-to-moderate exercise (like walking) can make a big difference.
• Gradually increase intensity if you can.

Exercise also helps improve sleep quality, which can further ease fatigue.

3. Eat Smaller, Balanced Meals

Instead of large meals, aim for smaller, frequent meals to stabilize energy. Focus on foods that include:

• Healthy fats
• Lean proteins
• Complex carbohydrates (like whole grains and vegetables)

Balancing your blood sugar levels can prevent energy crashes.

4. Prioritize Restful Sleep

Fatigue may simply mean you're not getting enough or good-quality sleep. Try to get 7–9 hours per night and improve your sleep hygiene:

• Establish a calming bedtime routine (like progressive muscle relaxation)
• Practice mindfulness or meditation during the day
• Exercise regularly, preferably outdoors• Get natural light exposure during the day
• Keep your bedroom cool, dark, and quiet at night

5. Talk to Your Healthcare Provider

If fatigue persists even after making lifestyle changes, consult your healthcare provider. They may:

• Slow your dose escalation
• Test for other issues like anemia, thyroid problems, or medication interactions

Feeling fatigued while taking Mounjaro or Zepbound is common but manageable.By staying hydrated, eating wisely, moving your body, prioritizing sleep, and working with your healthcare team, you can minimize tiredness and stay on track with your weight loss or diabetes management goals.

Always listen to your body—and don’t hesitate to ask for support if you need it!