Starting Mounjaro: What the First Month Really Feels Like
If you’re considering starting Mounjaro or have just taken your first dose, you’re probably feeling a mix of excitement and nerves. I get it. After trying just about every weight loss method under the sun, from strict calorie counting to extreme workout plans, I know what it’s like to start something new with cautious optimism. This blog isn’t written by a medical expert, and I’m not here to give clinical advice. I’m simply sharing what I wish I’d known during my first month using Mounjaro. Whether you’re totally new to it or just curious about the early experience, I hope this helps.
The Basics: What Is Mounjaro and Why It’s Different
Mounjaro (tirzepatide) is a medication developed by Eli Lilly, primarily for people with type 2 diabetes, though it’s increasingly known for its role in weight management. It’s a once-weekly injection that mimics two hormones—GLP-1 and GIP—which help regulate blood sugar and reduce appetite. You’ve probably heard of Ozempic or Wegovy. Mounjaro works in a similar way, but its dual-action effect is one of the reasons many people feel it’s more effective. In a large phase 3 clinical trial known as SURMOUNT-1, participants lost an average of 15.7% of their body weight over 72 weeks when taking the highest dose of Mounjaro, compared to just 3.3% with placebo. That’s a huge deal. You can read the full trial data here.
Week 1: Starting Off Slow
Most people start on the lowest dose to minimise side effects and allow their body to adjust. For me, the first week was more about paying attention than doing anything drastic. The appetite suppression wasn’t immediate, but I did notice subtle changes—like feeling fuller sooner and not constantly thinking about food. It’s not that Mounjaro made me lose all interest in eating overnight. It’s more like the volume dial got turned down. The constant mental noise around snacking and cravings was still there but quieter. One big tip: drink lots of water. Some people report mild nausea or constipation in the early days, and hydration really helps.
Week 2: Appetite Changes Kick In
This is where things got more noticeable. Meals became smaller naturally, not because I was forcing myself. I’d start to eat and just not finish. It wasn’t willpower—it was like my body genuinely didn’t want any more. A couple of things became clear:
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Meal planning became important. You won’t be eating as much, so make it count. High-protein foods kept me feeling satisfied longer.
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Side effects varied day to day. Some mornings I felt slightly nauseous, especially if I skipped breakfast or didn’t drink enough water.
For anyone else at this stage, I’d say: don’t panic if you don’t feel dramatic results immediately. Everyone’s body reacts differently. Some feel the appetite drop within a day, others after a couple of weeks. Either way, stay consistent and give it time.
Week 3: Learning to Listen to Your Body
By week three, I noticed how much my relationship with food was changing. It wasn’t just about eating less—it was about eating differently. I used to eat out of habit or boredom. Now, I was more mindful. If you’re in this stage, you might find yourself feeling a bit weird about wasting food or not clearing your plate. That’s normal, especially if you’ve been brought up with the whole “finish what’s on your plate” mentality. The truth is, your body will tell you when it’s had enough. Mounjaro helps you tune into those signals.
Some people report fatigue or low energy at this point. I found that eating more nutrient-dense meals and avoiding long gaps between food helped. It’s not the time for ultra-low-calorie diets—your body still needs fuel, just less of it.
Week 4: Seeing Progress Without Obsession
By the end of the first month, I’d noticed visible changes. Not massive, but enough that clothes fit better and I felt lighter. The scale had moved, but more importantly, my mindset had too. I wasn’t obsessing over food or feeling deprived. That, for me, was the biggest win. It’s tempting to want rapid results, especially if you’ve struggled with weight for years. But Mounjaro isn’t about dropping a stone in a week. It’s about long-term, sustainable change. And that starts with consistency, not perfection.
One thing that helped was tracking progress in ways that weren’t scale-related. Here are a few ideas:
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Take weekly photos in the same clothes and lighting.
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Notice changes in how your clothes fit.
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Keep a short journal on energy levels, mood, and appetite.
These things show progress better than the numbers on a scale ever could.
Common Side Effects and How I Managed Them
Let’s talk about the less glamorous side. Most people experience some mild side effects early on, but they tend to ease off. Here’s what I noticed and what helped:
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Nausea: Drinking water steadily through the day and not letting my stomach go completely empty helped.
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Constipation: Fibre-rich foods, a probiotic supplement, and magnesium made a big difference.
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Bloating or gas: Eating slowly and avoiding very fatty or greasy foods helped avoid discomfort.
Again, it’s all about learning what works for your body. Everyone is different, so what worked for me may not be perfect for you, but it gives you somewhere to start.
Tips for a Smooth First Month
Here are a few things I wish someone had told me earlier:
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Set a consistent injection day and time each week. Routine matters.
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Avoid high-fat, rich meals in the early weeks—they can intensify side effects.
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Don’t stress if the scale doesn’t move straight away. Progress takes time.
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Plan smaller, balanced meals and snacks ahead of time to avoid decision fatigue.
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Don’t compare yourself to others—this journey is yours, and results vary massively.
Mental Shifts That Matter
One of the most unexpected parts of this journey has been how much Mounjaro affects your mindset. When food isn’t taking up 80% of your brain space, you start noticing other things—like how tired you are, how you deal with emotions, or what you want to do with your newfound energy. The first month is the start of a bigger change, not just on the outside, but inside too. You might find it helps to journal your thoughts or talk to others going through a similar experience. There are plenty of supportive communities online (like Reddit’s r/Mounjaro) where people share honest insights, tips, and encouragement.
The Bigger Picture
To give some perspective: according to the NHS, around 1 in 4 adults in England are living with obesity. That’s millions of people who may be struggling with weight, health conditions, or just the mental load that comes with years of dieting. Mounjaro isn’t a magic fix, but it’s a powerful tool—and if used correctly, with patience and care, it can be life-changing. The first month might not be perfect, but it’s the foundation for what comes next.
Final Thoughts
If you’re just starting Mounjaro, know this: you’re not alone. The first few weeks are about learning, adjusting, and being kind to yourself. The weight loss is great, but the shift in mindset—that quiet confidence that things are finally clicking—is even better. Keep showing up for yourself. One day at a time.
