WEIGHT loss jabs have been a godsend for people in the UK living with obesity.
But despite 1.5 million people using the weight loss medication in a single month, many users say they haven’t seen the expected results from GLP-1 treatments.
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ZAVA, an online doctor site, claims up to 20 per cent of users don’t see the expected results from GLP-1 treatments. This is based on what several obesity experts told The Associated Press in 2024.
Weight loss plateaus are common, but in many cases, the reasons are identifiable and fixable.
To help those facing this challenge, experts at ZAVA have broken down the most common reasons the weight loss injection Mounjaro may not be working as expected – and what you can do to get back on track.
1. Incorrect medicine
Mounjaro’s effectiveness often increases as you move up the dosage ladder.
The medication is introduced to the body slowly (titration) to reduce side effects, eventually reaching maintenance doses of up to 15mg per week.
If you’re still on a lower dose or haven’t advanced as recommended, your weight loss may be limited.
Consistency is crucial. Skipping doses, delaying titration, or not following your provider’s schedule can reduce the medication’s impact.
Many people don’t feel the full effect until eight to 12 weeks in, so patience and adherence are key.
You should give Mounjaro at least three months before judging its effectiveness.
If you’re experiencing side effects, it’s absolutely fine to remain at a lower dose for longer.
The experts advise stepping up more slowly if you’re not tolerating side effects well – there’s no need to push through discomfort.
You can always increase the dose later once your body has adjusted.
Comfort and tolerability are just as important as consistency for long-term success.
Poor diet and lack of exercise
While Mounjaro helps reduce appetite, it doesn’t override the fundamental rule of weight loss: you must burn more calories than you consume.
Even with a smaller appetite, eating more than your body needs will still cause progress to stall.
To maintain an effective calorie deficit for weight loss, men are generally advised to consume around 1,900 calories per day (down from the typical 2,500), while women should aim for about 1,400 calories per day (down from around 2,000).
Healthy diet tips:
- Be strict with calorie tracking until portion control becomes second nature
- Aim for a 600-calorie daily deficit to lose weight steadily
- Prioritise whole foods over high-sugar, high-fat processed options
- Follow a diet plan tailored to your needs, and explore healthy recipe ideas to stay on track
The experts say to also remember that initial weight loss may come from water, especially if you’ve reduced salt or started exercising.
As your body adjusts, weight loss may temporarily plateau or appear to reverse.
Finally, stay hydrated and limit alcohol.
Alcohol can interfere with your metabolism and reduce the effectiveness of Mounjaro.
3. Stress and sleep issues
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Chronic stress and poor sleep are major weight loss blockers.
Stress increases cortisol, a hormone linked to fat retention, especially around the abdomen.
Sleep deprivation increases ghrelin (hunger hormone) and decreases leptin (fullness hormone), making you more likely to overeat and less likely to move.
You’re also more impulsive and less motivated when sleep-deprived, making it harder to stick to your diet and exercise routine.
As a solution, the experts say to prioritise stress management techniques (like mindfulness or journaling), and aim for seven to nine hours of sleep per night.
4. Health conditions and medications
Medical issues such as PCOS, diabetes, hypothyroidism, or insulin resistance can all interfere with weight loss.
Similarly, certain medications (like antidepressants or steroids) may cause weight gain or inhibit fat loss.
If weight loss stalls despite doing everything right, consult your GP to rule out or address any underlying conditions.
If you have a known medical condition, it’s important to stay up to date with your routine reviews and inform your GP or specialist about any weight loss treatments you’re using.
The experts advise regular follow-up helps ensure your treatment plan remains safe and effective.
5. Unrealistic expectations
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It’s natural to hope for rapid results, especially with a promising medication like Mounjaro.
But weight loss is a long-term process. Initial drops (often water weight) can be misleading.
Progress will slow, and that’s okay.
Avoid comparing yourself to others or obsessively checking the scale, say the experts.
Focus on consistency, not speed. Your journey is unique, and sustainable weight loss takes time.
6. Lack of support
Motivation by itself often isn’t enough. Without support from those who understand your goals, the journey can feel lonely and overwhelming.
The experts recommend:
- Lean on friends and family who encourage you
- Join online communities or local support groups, including NHS-recommended programs
- Consider working with a dietitian or coach for personalised guidance and accountability
How to boost weight loss on Mounjaro, according to a doctor
Dr Crystal Wyllie, a qualified and UK registered doctor who is part of the clinical team at Asda Online Doctor by ZAVA, says while Mounjaro is an effective medication for weight loss, it’s normal to encounter a plateau at some point.
She advises: “To enhance your results, it’s important to follow the prescribed dosing schedule and aim to reach the appropriate maintenance dose, as higher doses are generally associated with greater benefits.
“However, if you’re experiencing side effects, it’s perfectly acceptable to step up more slowly.
“Your GP may recommend staying on a lower dose for longer until your body adjusts, comfort and tolerability should always guide the pace of titration.”
Beyond medication, factors like maintaining a balanced diet, regular physical activity, managing stress, and getting enough sleep play a vital role in supporting your weight loss journey, says Dr Wyllie.
She adds: “If progress stalls despite these efforts, consulting your healthcare provider is essential to evaluate your plan and make necessary adjustments.”
For individuals who find Mounjaro less effective or unsuitable, there are several other weight loss medications to consider.
Dr Wyllie recommends: “Injectable options like Wegovy and Nevolat work similarly by curbing appetite, while oral medications such as Orlistat, Xenical, and the over-the-counter Alli provide different mechanisms to support weight loss.
“Each treatment has unique advantages and considerations, so working closely with your doctor ensures you receive the safest and most personalised approach to achieve your goals.”
Before beginning any weight loss treatment, please consult your GP or healthcare professional. These treatments may not be suitable for everyone.
