Dr Nick Fuller
Leading Obesity Expert at the University of Sydney and founder of Interval Weight Loss.
Weight loss injections such as semaglutide and tirzepatide have become a genuinely effective option for people struggling with overweight or obesity. These medications, which mimic gut hormones to reduce appetite and improve glucose regulation, have shown average weight losses well beyond what typical diet and exercise achieve. But what happens when you stop taking them? This article explores that question thoroughly, combining scientific evidence with engaging, practical insights.
Whether you’re approaching your target weight, dealing with side effects, or considering stopping for lifestyle reasons, it’s important to understand how your body may adapt. Let’s walk through how these medications affect your body, why people stop, what physiological changes can occur afterwards and actionable tips to keep progress steady even without injections.
Weight loss injections such as GLP-1 receptor agonists (like semaglutide) and dual GLP-1/GIP agonists (like tirzepatide) work by mimicking hormones that signal fullness and regulate appetite. When these drugs bind to receptors in the brain and gut, they reduce hunger, slow gastric emptying and improve insulin sensitivity, which helps lower calorie intake and support metabolic health. Clinical studies show these mechanisms lead to significant improvements in body weight, waist circumference and cardiometabolic markers compared with lifestyle changes alone.
These medications also influence reward pathways in the brain, decreasing cravings for high-energy foods and sugary snacks, which is one reason why many people find it easier to stick to healthier eating patterns while on treatment. Over time, consistent reductions in appetite and caloric intake contribute to gradual, clinically meaningful weight loss.
People stop weight loss injections for a variety of reasons: some medically advised, others personal or practical.
Many people discontinue once they’ve reached a pre-determined goal, under the guidance of their healthcare provider. Achieving target weight can be empowering, but it’s important to transition to sustainable habits to maintain results. Doctors often recommend a structured plan for tapering and lifestyle support before stopping.
Some individuals stop due to side effects like nausea, digestive discomfort or fatigue, especially during dose escalation. Even though side effects often lessen over time, they can be discouraging or impact quality of life enough for someone to decide it’s not worth continuing. Discussing adjustments or alternatives with a clinician can sometimes help.
Weight loss injections can be expensive, particularly without insurance coverage or where subsidies are limited. Cost concerns often lead people to discontinue even if results are good, making long-term budgeting for treatment a practical consideration.
Doctors may advise stopping due to pregnancy planning, new medical conditions, or concerns about interactions with other medications. Clinical judgement ensures that treatment remains safe and appropriate for an individual's overall health context.
Because these medications can affect fetal development, people planning pregnancy are usually advised to discontinue them. Pre-conception counselling with a healthcare provider helps balance weight management goals with reproductive health.
Some people transition away from injections as they adopt new habits that support weight management, such as refined eating patterns or consistent exercise, and choose to maintain weight without medication.
Supply chain issues or regional prescribing restrictions can make consistent access difficult, prompting some to stop. This is more common in areas where demand has surged faster than supply.
If someone doesn’t see the changes they were hoping for, they might conclude the injections aren’t effective for them. It’s important to differentiate between early patience required for results and disappointing progress, ideally with professional guidance.
The outcomes below are drawn from a large systematic review and meta-analysis of 18 randomised controlled trials, including 3,771 participants. The analysis examined what happens when GLP-1 weight loss injections are discontinued and identified clear, repeatable trends in weight and metabolic health across people with obesity and those with type 2 diabetes.
Weight regain is likely – After stopping treatment, individuals with obesity regained an average of around 5.6 kg, while people with type 2 diabetes regained roughly 2.0 kg on average.
Blood glucose control can worsen – HbA1c levels tend to rise following discontinuation, signalling reduced long-term blood sugar control, particularly among people with diabetes.
BMI and waist measurements increase – Indicators associated with body fat, including BMI and waist circumference, showed notable increases once injections were ceased.
Blood pressure may increase – Systolic blood pressure rose after stopping GLP-1 therapy, with more pronounced changes observed in those previously using semaglutide.
Longer time off treatment means greater regain – Weight regain was significantly higher when follow-up extended beyond 26 weeks compared with shorter periods after stopping.
Some GLP-1 medications have stronger rebound effects – Stopping semaglutide was linked to larger increases in weight, waist circumference and blood pressure than stopping liraglutide.
Other metabolic markers may decline – Fasting glucose levels and lipid-related markers showed signs of deterioration, especially in people with obesity.
These effects are driven by biology, not motivation – The evidence suggests rebound changes occur because the appetite and metabolic regulation provided by the medication is removed, rather than due to poor adherence or lack of willpower.
Stopping injections doesn’t mean the journey is over. Your body will adjust in different ways. Read Weight Loss Plateau Solutions to learn how your metabolism adapts, why some weight might return, and strategies to maintain results.
After stopping weight loss injections, it’s common to see some weight regain or shifts in appetite. While this can feel frustrating, there are practical strategies you can adopt to help manage your weight, support your metabolism, and maintain the progress you’ve made.
Eating adequate protein helps maintain fullness and preserve lean muscle, which supports metabolism. High-protein foods also have a higher thermic effect, meaning your body uses more energy to digest them.
Fibre from vegetables, whole grains and legumes slows digestion and enhances fullness after meals. It also supports digestive health and stabilises blood glucose levels, helping reduce cravings.
Large portions can easily undo calorie goals even if foods are healthy. Tools such as portion plates or visual cues (e.g. fist-sized protein, half plate vegetables) can help manage intake without feeling restrictive.
Exercise not only burns calories but supports insulin sensitivity and mood. Aim for a mix of cardiovascular activity, strength training and daily movement to sustain metabolic health.
Frequent grazing without hunger cues can add extra calories. Setting regular meal and snack times helps ensure eating is intentional and balanced.
Water supports metabolism, digestive function and can reduce false hunger signals. Sometimes thirst masquerades as hunger, leading to unnecessary snacking.
A regular eating rhythm helps stabilise hunger hormones and prevents overeating later in the day. Planning meals ahead can reduce impulsive choices.
Aiming for 7–9 hours of quality sleep supports hormonal balance, reduces cravings and improves energy levels. Poor sleep is consistently linked to weight gain in clinical research.
Stress influences appetite and food choices via cortisol pathways. Practices such as mindfulness, walking outdoors or breathing exercises can keep stress-driven eating in check.
Weighing weekly (not daily) helps you notice patterns without getting obsessed with fluctuations. Early detection of upward trends lets you adjust habits before larger gains occur.
Stopping weight loss injections doesn’t mean failure. It means shifting into a new phase where lifestyle supports take centre stage. With awareness of how your body changes and strategies grounded in research, you can manage your weight confidently and sustainably beyond medication.
Understanding what to expect after stopping can help you plan for long-term success. Read How Long Do You Stay on Weight Loss Injections to see typical timelines, how to transition safely, and tips to preserve your hard-earned progress.
Dr Nick Fuller is the founder of Interval Weight Loss and is a leading obesity expert at the University of Sydney with a Ph.D. in Obesity Treatment. Dr Fuller is also the author of three best-selling books and his work been published in top ranked journals in the medical field, including JAMA, Lancet and American Journal of Clinical Nutrition.