Evidence from clinical trials
Research comparing different tirzepatide doses provides a clear pattern of how weight loss varies by dose.
The landmark SURMOUNT-1 trial studied 2,539 adults without diabetes taking Mounjaro. Results showed:
| Tirzepatide Dose |
Average Weight Loss (72 weeks) |
| 5 mg |
15.0% |
| 10 mg |
21.4% |
| 15 mg |
22.5% |
| Placebo |
2.4% |
This trial demonstrated that Mounjaro produced stronger results than other weight-loss medications, with the 15 mg dose producing approximately 6.5% more weight loss than the 5 mg dose.
For context, Wegovy (semaglutide) typically achieves around 15% weight loss at its maximum dose of 2.4 mg.
A direct comparison with Wegovy was conducted in the SURPASS-2 trial (for diabetes patients), showing that Mounjaro’s middle dose of 10 mg outperformed Wegovy’s maximum dose.
The SURMOUNT-3 trial examined how well people maintained weight loss on Mounjaro after initial weight loss through diet alone. After switching to medication:
- The 10 mg group lost an additional 10.9% of body weight
- The 15 mg group lost an additional 11.2% of body weight
This suggests that at the highest doses, the differences between 10 mg and 15 mg may be smaller than the differences between lower doses.
Key points:
- Higher doses consistently produce greater average weight loss
- The relationship between dose and weight loss isn’t perfectly linear
- The biggest percentage improvement often occurs between 2.5 mg and 10 mg
- The 15 mg dose provides approximately 6-7% additional weight loss compared to 5 mg
- All Mounjaro doses outperform other weight-loss medications at their maximum doses
Dose-response relationship
Understanding how your body responds to increasing doses of Mounjaro helps set realistic expectations.
The science behind increasing doses
Mounjaro works through a dual-action mechanism, mimicking two hormones: GLP-1 and GIP. This differs from medications like Wegovy, which only target GLP-1.
Higher doses mean more of the active drug circulating in your bloodstream, leading to:
- A greater impact on lowering hunger
- Slower digestion
- Enhanced effects on fat metabolism
- Additional impact on blood sugar control
Mounjaro’s unique dual-action mechanism is likely one reason why tirzepatide leads to greater weight loss than single-mechanism medications.
However, our body’s receptors can become partially saturated at certain doses (meaning there’s a point where adding more medication doesn’t create proportionally more effect, similar to how a sponge can only absorb so much water), which explains why doubling the dose doesn’t necessarily double the weight loss effect.
Diminishing returns at higher doses
Research shows a pattern of diminishing returns as doses increase:
- The jump from 2.5 mg to 5 mg often produces a significant decrease in hunger and appetite
- The increase from 5 mg to 10 mg typically yields substantial additional benefits
- The step from 10 mg to 15 mg shows more modest improvements
This relationship explains why some people maintain successfully on middle doses (like 5 mg or 10 mg) without needing to reach the maximum dose.
UK prescribers increasingly recognise that the optimal dose may not always be the maximum dose, particularly when considering cost, side effects, weight loss goals, and individual responses.
Key points:
- Higher doses lead to stronger effects on appetite and metabolism
- Benefits increase with each dose step, but at a decreasing rate
- Some people reach their personal ‘optimal dose’ before the maximum 15 mg
- The ideal dose balances maximum effectiveness with minimum side effects
- Mounjaro’s dual-action mechanism may contribute to its greater effectiveness compared to single-mechanism medications
Individual factors affecting results
Your personal response to Mounjaro doses depends on multiple factors beyond the medication itself.
Genetic variation
Research suggests that genetics may partly explain why people respond differently to doses:
- Variations in the GLP-1 and GIP receptor genes can make some people more sensitive to even low doses
- Differences in metabolism genes affect how quickly Mounjaro breaks down in your body
- Some people naturally produce more GLP-1 and GIP, potentially affecting how they respond to medications
Studies suggest that genetic factors may explain why some people achieve exceptional results on lower doses while others require higher doses for similar effects.
Starting weight and BMI
Your baseline weight significantly impacts both absolute and percentage weight loss:
- People with higher starting weights often lose more total weight (in kg)
- Those with lower starting BMIs may see smaller absolute losses but similar percentage changes
- Starting BMI over 35 is associated with greater benefit from reaching maximum doses
SURMOUNT-1 data showed that people with higher baseline BMIs tended to benefit more from the highest dose compared to those with lower starting BMIs.
Medication consistency
How consistently you take Mounjaro matters more than the dose for many people:
- Missing doses can significantly reduce effectiveness regardless of dose
- Consistent weekly injections at a lower dose often outperform inconsistent use of higher doses
- The medication’s active duration means consistency supports stable blood levels
Activity level and nutrition
Your lifestyle significantly influences how well each dose works:
- Regular physical activity may improve weight loss outcomes in the long term while on Mounjaro as increased fitness levels are linked to improved hunger signalling
- Higher protein intake (a portion the size of an open hand in each meal) supports greater fat loss while preserving muscle
- Eat a diet based mainly on whole foods as consuming a higher intake of ultra-processed foods can lead to overeating, even on GLP-1 medications
- Having support to develop healthy habits can also lead to more weight loss. Research on Second Nature’s programme suggests those on Wegovy lose 3-6% more weight than Wegovy participants in clinical trials. This suggests the added support of our programme could encourage more weight loss in the long term.
Key points:
- Individual genetic factors cause significant variation in dose response
- Your starting weight and body composition affect your results at each dose
- Consistency in taking the medication matters more than the dose for many people
- Lifestyle factors like diet quality and physical activity can enhance or diminish dose effectiveness
- Structured support programs may improve outcomes at any dose level
Side effects at different doses
Side effect frequency and intensity typically increase with higher doses of Mounjaro, which may influence your optimal dose.
Common side effect patterns by dose
Research shows a clear correlation between dose and side effects:
| Dose |
Nausea Rate |
Vomiting Rate |
Diarrhoea Rate |
| 2.5 mg |
11-15% |
4-6% |
7-12% |
| 5 mg |
16-21% |
6-8% |
12-16% |
| 10 mg |
22-28% |
8-11% |
16-21% |
| 15 mg |
24-30% |
10-12% |
20-23% |
These figures from clinical trials indicate that side effects increase with dose, but the relationship isn’t strictly linear.
Many side effects also tend to improve over time at each dose level, with most people reporting significant improvement after 2-4 weeks.
Tolerability
Individual tolerability varies widely:
- Some people experience minimal side effects even at the highest dose
- Others find lower doses more manageable for long-term use
- Side effects may impact quality of life, work performance, and medication adherence
Balancing effectiveness with comfort
When determining your dose, consider:
- Whether additional weight loss at higher doses outweighs increased side effects
- If side effects interfere with your daily activities or quality of life
- How long side effects persist after dose increases (typically 2-4 weeks)
The right dose is usually the one that gives you results you’re happy with, without side effects becoming too bothersome.
Key points:
- Side effect frequency and intensity generally increase with higher doses
- Individual tolerability varies significantly
- Most side effects improve within 2-4 weeks at each dose level
- Finding your optimal dose often means balancing progress with side effects
How to find your ideal Mounjaro dose
Making an informed decision about your Mounjaro dose involves multiple considerations beyond just weight loss potential.
When higher doses make the most sense
Pushing to higher doses may be particularly beneficial if:
- Your BMI is over 35, where maximum weight loss provides greater health benefits
- You’ve had minimal side effects during titration
- You’re experiencing a weight loss plateau at lower doses
- You have significant weight-related health conditions requiring rapid improvement
- Cost is not a major concern
When remaining at lower doses might be preferable
Staying at lower doses (5-10 mg) might be appropriate if:
- You’re losing weight at a sustainable rate of 1-2 lbs (0.5-1 kg per week)
- Side effects are significantly impacting your quality of life
- You’re approaching your target weight
- Cost is a concern
- You’re planning for long-term maintenance
NHS prescribing
Current NHS guidelines typically recommend titrating to the maximum tolerated dose up to 15 mg.
However, maintenance at lower doses is becoming more accepted when:
- The patient is achieving good results
- Higher doses cause problematic side effects
- The patient’s weight-related health markers are improving
- The patient has developed sustainable lifestyle habits
Always discuss dose decisions with your healthcare provider, who can help evaluate your individual circumstances.
Key points:
- Higher doses make most sense for higher BMIs and minimal side effects
- Lower maintenance doses may be appropriate when you’re already seeing good results
- NHS guidance is evolving to support personalised dose optimisation
- The “best” dose is highly individual and depends on your specific circumstances
- Consider both short-term results and long-term sustainability when choosing a maintenance dose
Frequently asked questions
Will I lose weight on all doses of Mounjaro?
Yes, all doses of Mounjaro from 2.5 mg to 15 mg have demonstrated significant weight loss in clinical trials. Even the lowest therapeutic dose of 5 mg produces an average of 15% weight loss over 72 weeks, which exceeds the results of most other weight-loss medications at their maximum doses.
The starting dose of 2.5 mg is primarily used for titration to minimize side effects rather than as a long-term treatment dose.
Does Mounjaro wear off around day 5?
Some people report an increase in hunger around 5 days after taking their injection in the first 4-8 weeks.
This is because it takes around 4-8 weeks for Mounjaro to reach its ‘steady state’, which is when the blood levels of the drug remain stable.
After 4-8 weeks, hunger levels should remain consistent between injections.
Why might I still be hungry on the highest dose?
Several factors could explain hunger on the highest dose:
- Individual genetic variations in natural GIP and GLP-1 activity
- Emotional or environmental eating triggers that override physical hunger signals
- Development of some tolerance to the medication’s effects
- Habits: Our diet, sleep, stress, and activity levels all influence how well we respond to the medication
If you’re experiencing significant hunger on 15 mg, focus on protein intake, sleep quality, stress management, and environmental factors that might be triggering hunger.
Where is the best place to inject Mounjaro?
Mounjaro can be injected into the thigh, abdomen, or upper arm. The manufacturer doesn’t specify one site as more effective than others.
Some people report slightly different side effect patterns depending on injection site, but there’s no evidence this affects weight loss results. Rotating injection sites helps prevent tissue changes that could affect absorption.
Can I take a lower dose of Mounjaro for maintenance after reaching my goal weight?
Yes, many healthcare providers now support using lower maintenance doses (5-10 mg) after reaching your goal weight.
Key points to remember
The higher doses of Mounjaro typically lead to greater weight loss, with approximately 6-7% additional weight loss when increasing from 5 mg to 15 mg doses.
However, the relationship isn’t perfectly linear, and many people achieve significant results at middle doses.
Your optimal dose depends on multiple factors, including your starting weight, side effect tolerance, genetics, and cost considerations.
While the 15 mg dose produces the largest average weight loss in clinical trials, the difference between middle and maximum doses is smaller than the difference between starting and middle doses.
Working with your healthcare provider to find your personal ‘sweet spot’ dose, one that balances effectiveness with side effects and cost, often works best in the long run.
For many people, this optimal dose may be lower than the maximum 15 mg, especially when combined with healthy eating habits and regular physical activity.
Remember that consistency with your medication schedule and lifestyle changes often matters more than reaching the highest possible dose.
The best dose is ultimately the one that helps you achieve your health goals while maintaining a good quality of life.
Second Nature's Mounjaro and Wegovy programmes
Second Nature provides Mounjaro or Wegovy as part of our Mounjaro and Wegovy weight-loss programmes.
Why choose Second Nature over other medication providers, assuming you're eligible?
Because peace of mind matters.
We've had the privilege of working with the NHS for over eight years, helping people across the UK take meaningful steps toward a healthier, happier life.
Our programmes are designed to meet people where they are, whether that means support with weight loss through compassionate one-to-one health coaching, or access to the latest weight-loss medications (like Mounjaro and Wegovy) delivered alongside expert care from a multidisciplinary team of doctors, psychologists, dietitians, and personal trainers.
At the heart of everything we do is a simple belief: real, lasting change comes from building better habits, not relying on quick fixes. We're here to support that change every step of the way.
With over a decade of experience, thousands of lives changed, and a long-standing record of delivering programmes used by the NHS, we believe we're the UK's most trusted weight-loss programme.
We hope to offer you something invaluable: peace of mind, and the support you need to take that first step.
