How Much Weight Can You Lose on Mounjaro in a Month?

When it comes to Mounjaro weight loss, most people lost 2-4% of their starting weight in the first month of use. These figures are supported by the SURMOUNT-1 clinical trial and are based on the initial dose of 2.5 mg.

So, someone weighing 100 kg can lose 2-4 kg, while a person at 120 kg might lose 2.4 to 4.8 kg. Because the first month on Mounjaro uses a low dose, weight loss is minimal, but the SURMOUNT-1 trial also showed that 72 weeks at the highest maintenance dose resulted in average weight losses of 20-22.5%.

It's only natural that you want to see how much weight loss you can achieve with Mounjaro, so we've put together this helpful guide. Please note that these are average figures only, and the amount of weight you lose depends on your dosage, starting weight, and lifestyle.

This guide is for people who are either considering or about to start Mounjaro treatment. Understanding how much weight you can realistically achieve helps set realistic expectations and can help you decide whether Mounjaro is worth trying.

Month 1: What to Expect

As with all weight loss injections, Mounjaro can cause side effects when you begin treatment. For this reason, everyone starts on the lowest dose of 2.5 mg. This allows the body to adjust to the treatment and ensures the side effects are manageable.

Appetite suppression usually occurs within the first week, where you'll feel less hungry and fuller after meals. While some people notice visible weight loss during weeks 2 and 4, it's a gradual process. SURMOUNT-1 data shows an average weight loss of 2-4 kg (4%) in the first few weeks.

In some cases, the side effects can result in weight loss due to nausea.

Example: Someone who weighs 90 kg at the start of Mounjaro could lose between 1.8 kg and 3.6 kg.

Month-by-Month Weight Loss Timeline

The following figures are based on data from the SURMOUNT-1 clinical trial, and your Mounjaro weight-loss results may vary month to month (Medicspot).

• Months 1–2: This is the slowest phase, as your body needs time to adjust to the weight loss medication.
• Months 3–6: Accelerated weight loss due to increased dosages and appetite suppression. Months 3- 6 are when people typically experience the highest monthly weight loss.
• Months 6–12: The body has adapted to the medication, resulting in slower, steadier weight loss. This is normal, and it doesn't mean the weight-loss treatment isn't working.
• Month 12+: Weight loss plateaus, and it's more about maintaining your weight rather than losing more. The results are still ongoing, as Mounjaro also supports weight management.

Why Results Vary: What Affects How Much You Lose?

Everyone's weight-loss journey is different, which can affect how much weight you lose. The main factors that impact your potential loss include:

• Starting Weight: It's natural for individuals with higher starting weights to experience faster results. While they drop more kg, the average weight-loss percentages remain the same.
• Dosage: Weight loss also depends on the dosage. In the SURMOUNT-1 trial, the results showed an average weight loss of 15% at 5 mg, ~19.5% at 10 mg, and ~20.9% at 15 mg. It's important to remember that not everyone reaches the 15 mg maintenance dose, as it depends on how the body adjusts to each dose.
• Diet and Exercise: The treatment offers reduced appetite, but it doesn't eliminate it completely. People who focus on dietary changes and healthy habits such as regular exercise are more likely to achieve sustainable weight loss. This includes increasing your protein intake to 0.8-1.3 grams per kg of body weight.
• Individual Factors: Other factors include a person's sleep quality, thyroid function, gut microbiome, and insulin resistance.
• Side Effects: Some people may experience more side effects, such as nausea, vomiting, and loss of appetite, than others, which can accelerate weight loss.
• Consistency: Mounjaro is a weekly weight loss injection. Not taking it each week can impact its effectiveness.

The NHS 12-Week Check

If you're prescribed Mounjaro through the NHS, you'll usually have a 12-week review to assess whether the medication is effective. If you haven't reached the 5% loss benchmark by this time, your prescriber may recommend trying other weight-loss injections.

However, this only applies when you're on maintenance doses and not the starting dose. These reviews are in place to evaluate whether your body is responding to its planned long-term dose, and can help your prescriber adjust your treatment plan.

Why Does Month 1 Often Feel Slower Than Expected?

It's common to feel like month-one weight loss is slower than you'd like, because social media shows extreme 6-week transformations. However, the 2.5 mg dose is the starting point that allows your body to get used to the medication.

The first four weeks on Mounjaro are about establishing a routine and dealing with the side effects. Some people may look like they've lost lots of weight, but this is usually water weight, and the results will stabilise.

If you haven't lost any weight during month one or experience weight gain, you should speak to your prescriber.

How to Get the Best Results in Month 1 and Beyond

Weight loss on Mounjaro is a very personal experience, and everyone's different. But if you want to give yourself the best chance of consistent weight loss, following these tips will help:

• Protein Is Key: Protein improves satiety and supports muscle mass. Aiming for 20-40 grams per meal (about a palm-sized amount) can support your weight-loss journey.
• Eat Regularly: Even though Mounjaro decreases your appetite, you should still eat regularly. Skipping meals can slow your metabolism and increase the risk of nutrient deficiencies.
• Hydration: Drink 6-8 glasses of water daily to reduce the risks of dehydration and protect kidney function.
• Lifestyle Changes: Focus on a balanced diet of protein, fibre, complex carbohydrates, and healthy fats. Regular exercise routines are also essential, including walking, swimming, or going to the gym.
• Be Patient: Don't expect miraculous weight loss in the first few weeks of treatment. Attend any follow-up appointments and express your concerns to the prescriber.

How Long Before You See Noticeable Results?

Most people notice a reduced appetite within 1-2 weeks of starting treatment, with fewer cravings and improved satiety during weeks 2-4. It's normal for weight loss to fluctuate each week during the early treatment phases, and noticeable changes typically occur around the 3-6 month mark.

Once you reach your standard maintenance dose, the weight loss will plateau, and it's more about maintenance. However, if you don't exercise regularly and consume a healthy diet, you could be at risk of weight gain.

How much weight do you lose in the first month of Mounjaro?

The average weight loss is 2-4% when starting Mounjaro. This can be due to fat loss and reduced water weight. If you don't lose at least 2%, it doesn't mean the medication isn't working.

How long does it take to see results on Mounjaro?

Most people notice accelerated weight loss starting in month 2, with months 3-6 showing the biggest drops. Once you reach your standard maintenance dose, it's more about preserving those losses instead of losing more weight.

Why am I not losing weight on Mounjaro in the first month?

Some people don't lose weight during the first month, and this can be completely normal. Month 1 is the lowest dose, as it gives your body a chance to adjust to weight loss medications. Some people don't notice any meaningful results until their dosage is increased.

What is the average Mounjaro weight loss after 3 months?

According to SURMOUNT-1 clinical data, people lose an average of 6-10% with increased doses from 5mg to 7.5mg. Again, this depends on how your body responds to the medication and whether you're practising healthy habits.

Can you lose a stone in a month on Mounjaro?

It's possible, but this would be classed as excessive weight loss rather than a stable decrease. Plus, if you experience extreme weight loss, it can impact your muscle mass. For this reason, your prescriber may decrease your dose.

Does Mounjaro work for everyone?

While Mounjaro is one of the most effective weight loss medications with proven data, it doesn't work for everyone. Individual responses can vary, and some people might not experience any weight loss. If this happens, your prescriber might recommend an alternative treatment such as Wegovy.