How Long Does Mounjaro Take to Work?

Mounjaro starts working within hours of the first injection by regulating appetite and improving metabolic function. However, visible weight loss results usually take a few weeks as the body adjusts to the medication.

Clinical studies suggest that Mounjaro users can lose up to 22.5% of their initial body weight when using the maximum dose of 15 mg over 72 weeks. For instance, an individual starting at 110kg could lose around 24.75kg by the end of the treatment period.

Treatment usually starts at 2.5 mg per week, with the dosage gradually increasing under medical supervision to optimise results while minimising side effects. This step-by-step approach allows the body to adapt to Mounjaro, making weight loss more sustainable.

Mounjaro Timeline for Weight Loss Progress

We have compiled this guide based on insights from the Surmount 1 trials to help you understand what to expect when using Mounjaro for weight loss. Since every individual’s body responds differently, your progress may vary. 

This timeline outlines the general expectations for dosage, weight loss, side effects, and tips to maximise results.

This timeline outlines the general expectations for dosage, weight loss, side effects, and tips to maximise results.

Week 1-4

Recommended dosage: Most users start with a 2.5 mg weekly dose to allow the body to adjust.

Weight loss: Initial changes are subtle, with some users experiencing 1-3% weight reduction.

What to expect: Appetite suppression begins, leading to reduced food intake. Blood sugar levels may stabilise, especially for diabetic patients.

Side effects: Common side effects include nausea, bloating, and mild fatigue as the body adapts.

Pro tip: Stay hydrated, eat smaller meals, and avoid high-fat foods to minimise nausea.

Week 5-8

Recommended dosage: After 1 month, the dosage is often increased to 5 mg weekly based on tolerance and physician guidance.

Weight loss: Noticeable progress, with some users losing up to 5-7% of their initial weight.

What to expect: Energy levels may improve as the body adjusts. More consistent appetite control helps with portion sizes.

Side effects: Digestive discomfort such as constipation or diarrhoea may persist but generally improves over time.

Pro tip: Maintain a high-protein diet to support muscle retention and keep cravings at bay.

Week 9-12

Recommended dosage: Some users may progress to 7.5 mg weekly for enhanced results.

Weight loss: Many users achieve around 10% total weight reduction by this stage.

What to expect: Increased metabolic changes, better portion control, and sustained appetite suppression.

Side effects: Some may still experience nausea, but symptoms generally lessen.

Pro tip: Stick to a regular exercise routine to complement weight loss and maintain muscle mass.

Week 13-16

Recommended dosage: Users tolerating 7.5 mg well may advance to 10 mg weekly.

Weight loss: Further progress, with up to 12-15% body weight reduction achieved.

What to expect: Your clothes start to lose and your energy levels will be arisen. 

Side effects: Digestive issues continue to subside, though mild fatigue may persist.

Pro tip: Prioritise nutrient-dense foods to support long-term metabolic health.

Week 17-20

Recommended dosage: Some patients may transition to 12.5 mg if additional weight loss is needed.

Weight loss: Weight reduction slows but remains steady, nearing 15-18% of initial body weight.

What to expect: Enhanced confidence and physical mobility, with well-controlled cravings.

Side effects: Most side effects diminish significantly by this stage.

Pro tip: Monitor body composition to ensure fat loss rather than muscle loss.

Week 21 and Beyond

Recommended dosage: Some users maintain 10-12.5 mg, while others transition to 15 mg for maximum results.

Weight loss: By six months, many users achieve a 20-25% reduction in total body weight.

What to expect: Sustainable weight loss, better metabolic health, and reduced risk of obesity-related conditions. By six months, many users achieve a 20-25% reduction in body weight. The long-term benefits extend beyond the scale as individuals maintain an improved quality of life, better sleep, and enhanced overall wellness.

Side effects: Minimal side effects remain for most users as their body adjusts to the medication at this stage. 

Pro tip: Regularly consult a healthcare provider to assess whether dosage adjustments or maintenance therapy are needed.

Factors Affecting Weight Loss with Mounjaro 

Mounjaro is effective, but several other factors determine how quickly and successfully you lose weight:

1. Your Starting Weight & BMI

– People with higher body weight tend to see more rapid initial weight loss.

– If you’re closer to your goal weight, progress may slow down, but every small step counts.

2. Your Overall Health

– Underlying conditions like insulin resistance, thyroid issues, or metabolic disorders can affect weight loss speed.

– Certain medications may also impact your progress—always consult your doctor if you have concerns.

3. Lifestyle & Habits

– Mounjaro reduces appetite, but your daily choices still matter.

– A high-protein, high-fibre diet combined with regular physical activity leads to better and faster results.

4. Natural Body Changes

– Weight fluctuates due to hormones, water retention, and stress—this is normal!

– Focus on long-term trends, not daily weigh-ins, to avoid unnecessary frustration.

How to Get the Best Weight Loss Results While Taking Mounjaro

1. Eat a Nutrient-Rich Diet

– Prioritise protein (lean meats, eggs, fish, tofu) to preserve muscle mass while losing fat.

– Add plenty of vegetables and fibre to your diet plan to support digestion and keep you full longer.

– Smaller, frequent meals may help if you experience discomfort from eating larger portions.

2. Stay Active

– You don’t need an intense workout routine—daily walks, stretching, or light strength training can help.

– Aim for 30 minutes of movement most days, but listen to your body and adjust accordingly.

3. Track Your Progress

Keep a journal or app to log weight changes, appetite shifts, and any side effects. This helps you and your doctor adjust your treatment plan if needed.

4. Manage Side Effects

– If you experience nausea, eat smaller meals and avoid greasy or spicy foods.

– Staying hydrated and getting enough sleep can also help with energy levels.

5. Seek Support

– Weight loss is easier when friends or family encourage you.

– Our healthcare experts at The Care Pharmacy are there to guide you—don’t hesitate to ask for advice.

Start Your Weight Loss Journey with The Care Pharmacy

If you’re ready to start Mounjaro, The Care Pharmacy is here to support you. Our expert pharmacists provide professional guidance to help you navigate your weight loss journey safely and effectively.

Complete an online consultation with The Care Pharmacy today, and our healthcare experts will help you achieve your weight loss goals.

FAQs

Does Mounjaro work immediately?

No, Mounjaro does not work immediately. It gradually builds up in your system over weeks. Some people notice a reduced appetite immediately, but significant weight loss and metabolic effects typically take weeks to become noticeable.

What to expect in the first week on Mounjaro?

In the first month of taking Mounjaro, you’ll probably notice a difference in your appetite. You might feel less hungry and get full more quickly, which can naturally lead to eating less and starting to lose weight. That said, you may also experience some side effects like nausea, diarrhoea, or indigestion as your body adjusts to the medication.

How quickly do you feel the effects of Mounjaro?

The appetite-suppressing effects can begin within a few days to a week. However, for substantial weight loss and blood sugar control, it generally takes 4 to 8 weeks to see noticeable changes.

How soon do you start losing weight on Mounjaro?

Most people start losing weight within 2 to 4 weeks of starting Mounjaro. However, the rate of weight loss depends on factors like diet, exercise, metabolism, and dosage.

Why am I not losing weight on Mounjaro 5mg?

If you’re not losing weight on Mounjaro 5mg, it may be because this is the lowest maintenance dose, and some people need a higher dose, like 7.5mg or 10mg, for noticeable results. Your body may still be adjusting, and weight loss can take time. Diet and activity levels are also key—without a calorie-controlled diet and regular exercise, progress may be slower. You might have hit a weight loss plateau where your body has adapted, requiring changes to your routine or dosage. Metabolic factors like insulin resistance, PCOS, or thyroid issues can also affect results. If weight loss stalls, speak to your healthcare provider about adjusting your dose or lifestyle.

How fast does Mounjaro work on appetite? 

Many people report feeling less hungry within the first few days to a week of starting Mounjaro. However, the appetite-reducing effects become stronger as the dosage increases and your body adjusts to the medication.

What are the results of Mounjaro after 1 month?

Studies suggest you could lose around 4% of your starting weight in the first month, but this varies for everyone. For example, if you weigh 15 stone, you might lose around 0.6 stone (8-9 lbs), though some may lose more or less depending on metabolism, diet, exercise, and lifestyle.

How long does it take to get used to Mounjaro?

Most people adjust within 2 to 4 weeks. Initially, side effects like nausea and digestive issues can occur, but they often subside as your body gets used to the medication. Eating smaller meals, avoiding fatty foods, and staying hydrated can help.

How much weight can you lose on Mounjaro in a month?

On average, weight loss with Mounjaro is around 5-10% of body weight over 3-6 months. In the first month, you may lose 4-10 lbs (1.8-4.5 kg), depending on diet, exercise, and dosage.

Higher doses and long-term use lead to greater weight loss, with some individuals losing 15-25% of their body weight over a year.