Weight stalled on obesity medication - when does treatment need to change?

When your weight stalls on obesity medication, the first step is to establish what stage of treatment you are at, because a stall means something different at each stage. In the first weeks, the patient takes a low starting dose, and the doctor increases it gradually to limit nausea, vomiting and diarrhoea. A stall during this time therefore says little about whether the medicine works. When the doctor judges whether the medicine is working depends on the medicine and the dose. The Polish Society for the Treatment of Obesity (PTLO) defines response to treatment as a loss of at least 5% of starting body weight; for semaglutide, it recommends assessment after 3 months on the 2.4 mg dose (1). After about a year of treatment, body weight usually stabilises. In a two-year semaglutide trial, body weight stopped going down after just over a year of treatment and stayed at a lower level until the end of the second year (2, 3). In none of these situations should you increase the dose on your own. Your doctor decides on the dose and on any change of medicine.

In brief

• On the starting dose of semaglutide (0.25 mg), tirzepatide (2.5 mg) or liraglutide (0.6 mg), it is too early to conclude that treatment is not working. Even at this stage, however, the doctor checks the change in body weight and how well you tolerate the medicine.
• PTLO defines response to treatment as a loss of at least 5% of body weight. For semaglutide, it recommends assessment after 3 months on the 2.4 mg dose. Liraglutide is stopped if body weight has not fallen by at least 5% after 12 weeks on 3 mg a day.
• Before deciding that a medicine is not working, the doctor asks about missed doses, checks your injection technique and looks at diet, physical activity and psychological factors. Only then does the doctor decide on further treatment, in line with the stopping rules for that medicine. Two obesity medicines should not be taken together.
• When weight stops going down after earlier weight loss, this is called a plateau. The medicine may then help you maintain the lower body weight. STEP 1 participants who were followed for a year after stopping semaglutide and ending the lifestyle programme regained, during that time, on average two thirds of the weight they had lost.

What does it mean when your weight stalls on obesity medication?

A weight stall on obesity medication happens in three different situations: during dose escalation, before you reach the therapeutic dose; after a period on the therapeutic dose, when weight loss is too small; or after a year of treatment, when body weight stabilises. Which one applies to you depends on how much time has passed since your first dose and what dose you are taking now.

How the dose and appetite change in the following months is described in our article on the first months of obesity treatment with medication. If you are not taking medication, the dose and the way the medicine is taken are not relevant, but it still helps to check your energy balance, sleep, other medicines and medical conditions. We discuss these in our article on what to check when you can't lose weight despite diet and exercise.

How often should you weigh yourself on obesity medication?

Body weight fluctuates from day to day, for example after meals and drinks, so a single reading says little about treatment. PTLO recommends weighing yourself once a week, in the morning, on the same scales and under similar conditions (1). Regular weighing is linked to a better chance of losing weight and keeping it off. In people with obesity, especially severe obesity, it can, however, cause stress and frustration, and some people then cope with the stress by eating. This is why the way body weight is monitored is agreed individually with each patient. In our programme, the patient weighs themselves once a week, and at the monthly medical check-up the doctor looks at the results from several weeks. If weighing yourself causes you stress, tell the doctor or the psychologist.

Why might your weight not go down on the starting dose of obesity medication?

Treatment starts at a low dose that is increased gradually to reduce the risk of nausea, vomiting and diarrhoea. The starting dose of semaglutide and tirzepatide is not a maintenance dose, that is, the dose a patient takes over a longer period. A stall in the first weeks therefore does not yet tell you whether the medicine will work.

Semaglutide treatment starts at 0.25 mg once a week, and the dose increases every 4 weeks (0.5, 1 and 1.7 mg) to the maintenance dose of 2.4 mg, which the patient takes from week 17 (3). Tirzepatide treatment starts at 2.5 mg once a week, and after 4 weeks the dose is increased to 5 mg. The maintenance doses are 5, 10 and 15 mg, and each further step of 2.5 mg requires at least 4 weeks on the current dose (4). Liraglutide is taken daily, starting at 0.6 mg a day, and the dose is increased by 0.6 mg no more often than once a week, up to 3.0 mg (5).

If nausea, vomiting or diarrhoea are severe, the doctor may delay the dose increase or go back to the previous dose until the symptoms ease (3). With semaglutide, reaching the 2.4 mg dose later also pushes back the planned assessment of effectiveness, which takes place after 3 months on that dose. In the STEP 1 trial, the average body weight of participants treated with semaglutide went down throughout treatment, from the first weeks (3). However, the change in body weight varies greatly between individual people treated for obesity. If your weight does not go down for a week or two during this period, that is not a reason to change treatment.

How does a doctor know that obesity medication is not working?

According to PTLO, a loss of less than 5% of starting body weight, meaning your weight before treatment began, is a reason to assess whether treatment is effective enough. The timing of this assessment depends on the medicine and the dose. With a starting weight of 110 kg, the 5% threshold is 5.5 kg.

For semaglutide, PTLO recommends assessment after 3 months on the 2.4 mg dose. With standard dose escalation over 16 weeks, this falls around the 7th month of treatment. For tirzepatide, there is no set point at which the medicine is stopped because of insufficient weight loss. The doctor sets the follow-up plan, taking into account the maintenance dose and how treatment is going (1, 4). Liraglutide and naltrexone/bupropion have their own stopping rules.

Sources for the table: the Polish guidelines (1) and official product information (3, 4, 5, 6).

Results from the first months on the therapeutic dose say a lot about what to expect later. In liraglutide trials, among people who had lost less than 5% of their body weight after 12 weeks on the 3 mg dose, 93.4% had not achieved a loss of at least 10% after a year (5). With naltrexone/bupropion, the result at week 16 correctly predicted in about 85 out of 100 cases whether weight loss after 56 weeks would be at least 5% (6).

The 5% threshold is not the only criterion. The doctor may consider continuing treatment despite a smaller weight loss if the control of conditions that accompany obesity, such as high blood pressure, diabetes or lipid disorders, has improved during treatment (1). In doing so, the doctor must still follow the stopping rules for liraglutide and naltrexone/bupropion given in the table.

What does a doctor check before deciding that obesity medication is not working?

According to PTLO, before a medicine is stopped, four reasons for a lack of effect need to be ruled out: not following the advice on diet and physical activity, obstacles to following it, psychological and social factors, and taking the medicine incorrectly (1). During the consultation, you will discuss the following with the doctor:

• Missed doses. A missed dose of semaglutide is given if no more than 5 days have passed since the scheduled day, and a missed dose of tirzepatide if no more than 4 days have passed. A missed dose of liraglutide is taken if it is still within 12 hours of the usual time. After that, the missed dose is skipped and you return to the usual schedule (3, 4, 5). After several missed doses of semaglutide, the doctor may restart treatment at a lower dose.
• Injection technique. The medicine is injected under the skin, in the sites shown in the leaflet. The single-use semaglutide pen must be held firmly against the skin until the yellow bar stops moving. The injection takes about 5-10 seconds (3).
• The dose you actually take. If you take less than the doctor prescribed because of the cost or side effects, tell the doctor. The assessment of effectiveness applies to the therapeutic dose.
• Eating and physical activity. The medicine reduces appetite, but it does not replace a reduced-calorie diet and physical activity, and the doctor should remind you of this at every appointment. How to plan your meals when your appetite is smaller is described in our article on what to eat on obesity medication.
• Emotional eating and binge eating. These are psychological factors that the doctor assesses before changing the medicine. We discuss their treatment in our article on binge eating.
• Other medicines and alcohol. Some medicines promote weight gain, so even before starting obesity treatment the doctor considers stopping them or switching to others. Do not stop them yourself: the decision is made by the doctor who prescribed them. You will find more details in our articles on weight gain caused by medicines and how alcohol affects obesity treatment with medication.

What does a doctor do if obesity medication is not working?

If, after these causes have been ruled out, weight loss still does not reach 5%, the doctor stops the medicine or switches to another one. In this situation, PTLO recommends considering a more potent medicine. Adding a second obesity medicine to the current one is not recommended, because there are no data on the effectiveness and safety of such a combination (1). The doctor chooses the next medicine based on the patient's health, coexisting conditions, cardiovascular risk and preferences. We explain separately how eligibility for obesity medication is assessed and what the choice of medicine depends on.

In the Nasz Gabinet obesity treatment programme, the doctor reviews the data from the app every month, that is, the weekly weigh-ins and monthly body measurements, and after each review decides on the next e-prescription: the same dose, a higher dose or a different medicine.

Why does weight stop going down after a year of obesity treatment?

In most patients, body weight stops going down after a certain period of treatment and stabilises at a lower level. In the two-year STEP 5 trial, body weight in people taking semaglutide stopped going down between weeks 60 and 68 and stayed at a similar level until the end of the trial. The trial publication gives about week 60, and the official product information week 68 (2, 3). After one year, body weight was on average 15.6% lower than at the start, and after two years 15.2% lower (2).

After weight loss, appetite increases and metabolism slows down. Using a mathematical model, Polidori and colleagues estimated that in the participants of the trial they analysed, energy intake rose by about 100 kcal a day for every kilogram lost. These calculations concerned people with type 2 diabetes who lost weight on canagliflozin, a medicine that increases the excretion of glucose in the urine (7). Weight loss also slows because of the hormonal and metabolic changes that accompany weight reduction. Obesity medication reduces appetite, but at a certain body weight its effect and these changes balance each other out, so your weight settles at a new, lower level.

How do you know obesity medication is still working when your weight has stalled?

This is shown by trials in which the medicine was stopped. In the STEP 1 trial, some participants were followed for a year after treatment ended. They had taken semaglutide for 68 weeks and lost an average of 17.3% of their body weight, then stopped the medicine and ended the lifestyle programme. Within a year, they regained on average about two thirds of the weight they had lost (11.6 of 17.3 percentage points), and blood pressure, blood glucose (glycaemia) and lipids mostly moved back towards their pre-treatment values (8). In the STEP 4 trial, people who switched to placebo after 20 weeks of semaglutide gained 6.9% over the next 48 weeks. People who continued treatment lost a further 7.9% during this time (9).

After earlier weight loss, the medicine may help you maintain your lower weight, even when your weight is no longer going down. Do not stop it on your own. How a doctor plans stopping obesity medication is described in a separate article.

What does a doctor do when your weight levels off after a year of obesity treatment?

The doctor compares the weight loss achieved with the goal set at the start and checks how your blood pressure, blood glucose and lipids have changed. In the plateau phase, it is possible to switch to a more potent medicine, but the doctor decides individually whether and when to do so. The doctor also takes into account the benefits of the current treatment for the heart and blood vessels. The calorie content of the diet is recalculated after a 10% weight loss or when body weight stops going down, because at a lower body weight the body needs less energy (1).

Semaglutide also has a 7.2 mg once-weekly dose. It can be used in adults who had a BMI of at least 30 at the start of treatment, after at least 4 weeks on the 2.4 mg dose. If the higher dose does not help control body weight better, the doctor goes back to 2.4 mg (3). Only your doctor can decide on this change.

Can you increase the dose of obesity medication yourself if your weight stalls?

No. The doctor increases the dose of obesity medication gradually, according to a set schedule, after checking how you tolerate the current dose.

Each medicine also has a maximum dose, for example 15 mg once a week for tirzepatide and 3.0 mg a day for liraglutide (4, 5). Increasing the dose gradually reduces the risk of nausea, vomiting and diarrhoea. These symptoms can lead to dehydration, and in rare cases dehydration can lead to worsening kidney function, including acute kidney failure (3, 4). Anyone who raises the dose faster than the schedule allows is more likely to get these symptoms. A missed dose must not be made up for with a double or extra dose; with liraglutide, you also must not increase the dose the next day (5). Whether to take a missed dose later depends on how much time has passed and on the medicine; the allowed intervals are described above.

If your appetite comes back before the next injection or your weight has not changed for several weeks, write it down and tell the doctor at the follow-up appointment. The doctor may increase the dose according to the schedule, keep it the same or change the treatment. You should also not stop the medicine or take breaks from it on your own.

Which symptoms after a dose increase of obesity medication need urgent medical attention?

Severe, long-lasting abdominal pain, which may also spread to the back, may be a symptom of acute pancreatitis; contact a doctor immediately (3). Vomiting that stops you keeping fluids down, or diarrhoea you cannot keep up with by drinking, also needs urgent assessment, because of the risk of dehydration. If you cannot contact a doctor quickly, go to a hospital emergency department (SOR). Other side effects and ways of coping with them are described in our article on side effects of obesity medication.

Frequently asked questions

Can obesity medication stop working after a few months?

If a stall appears after a few months, the first thing to check is whether the patient has already reached the therapeutic dose. In the two-year STEP 5 trial, the effect of semaglutide was maintained: after one year and after two years, participants weighed on average about the same, around 15% less than at the start. However, individual results varied greatly, and in a small proportion of participants body weight increased during treatment (2). If your weight is rising despite taking the medicine regularly at the therapeutic dose, the doctor looks for the cause: missed doses, changes in eating, new medicines or other conditions.

Do people with type 2 diabetes lose weight more slowly on obesity medication?

On average, yes. In trials of semaglutide 2.4 mg, people with type 2 diabetes lost on average 9.6% of their body weight over 68 weeks, and people without diabetes 14.9%. Greater weight loss was also seen in women and in people with a lower starting weight (3). In trials of tirzepatide 15 mg, weight loss after 72 weeks was 14.7% in people with type 2 diabetes and 20.9% in people without diabetes (10, 11). Semaglutide as Ozempic is licensed only for treating type 2 diabetes, at doses of up to 2 mg a week, and its dose is chosen to control diabetes (12).

Should you measure your waist when your weight stalls?

Yes. Waist circumference indirectly shows how much fat is stored around the organs in the abdomen, and therefore also the risk of heart and metabolic disease. Body weight alone does not show this, and according to PTLO, waist circumference is most informative as a risk indicator at a BMI below 35 (1). In our programme, the patient takes body measurements once a month, and the doctor assesses them together with weight. If your waist is getting smaller while your weight stays the same, show these measurements to the doctor. However, the criterion for the effectiveness of the medicine in the Polish guidelines is based on body weight.

If you switch medicines, do you have to wait again before the doctor can tell whether it works?

Yes. A new medicine is usually started at a low starting dose, which the doctor increases according to the schedule for that medicine. When the doctor judges whether it is working also depends on the new medicine. For example, for semaglutide PTLO recommends assessment after 3 months on the 2.4 mg dose, while liraglutide must be stopped if body weight has not fallen by at least 5% after 12 weeks on the 3 mg dose.

Sources

1. Bąk-Sosnowska M, Białkowska M, Bogdański P et al. Zalecenia kliniczne dotyczące postępowania u chorych na otyłość 2024 - stanowisko Polskiego Towarzystwa Leczenia Otyłości (Clinical guidelines for the management of patients with obesity - position statement of the Polish Society for the Treatment of Obesity). Medycyna Praktyczna, special edition, September 2024 (chapters 2, 5, 8 and 11). ptlo.org.pl
2. Garvey WT, Batterham RL, Bhatta M et al. Two-year effects of semaglutide in adults with overweight or obesity: the STEP 5 trial. Nat Med. 2022;28(10):2083-2091. PMID 36216945, DOI
3. European Medicines Agency. Wegovy (semaglutyd) - charakterystyka produktu leczniczego i ulotka dla pacjenta (summary of product characteristics and patient leaflet). ema.europa.eu
4. European Medicines Agency. Mounjaro (tirzepatyd) - charakterystyka produktu leczniczego (summary of product characteristics). ema.europa.eu
5. European Medicines Agency. Saxenda (liraglutyd) - charakterystyka produktu leczniczego (summary of product characteristics). ema.europa.eu
6. European Medicines Agency. Mysimba (naltrekson z bupropionem) - charakterystyka produktu leczniczego (summary of product characteristics). ema.europa.eu
7. Polidori D, Sanghvi A, Seeley RJ, Hall KD. How Strongly Does Appetite Counter Weight Loss? Quantification of the Feedback Control of Human Energy Intake. Obesity (Silver Spring). 2016;24(11):2289-2295. PMID 27804272, DOI
8. Wilding JPH, Batterham RL, Davies M et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension. Diabetes Obes Metab. 2022;24(8):1553-1564. PMID 35441470, DOI
9. Rubino D, Abrahamsson N, Davies M et al. Effect of Continued Weekly Subcutaneous Semaglutide vs Placebo on Weight Loss Maintenance in Adults With Overweight or Obesity: The STEP 4 Randomized Clinical Trial. JAMA. 2021;325(14):1414-1425. PMID 33755728, DOI
10. Jastreboff AM, Aronne LJ, Ahmad NN et al. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022;387(3):205-216. PMID 35658024, DOI
11. Garvey WT, Frias JP, Jastreboff AM et al. Tirzepatide once weekly for the treatment of obesity in people with type 2 diabetes (SURMOUNT-2): a double-blind, randomised, multicentre, placebo-controlled, phase 3 trial. Lancet. 2023;402(10402):613-626. PMID 37385275, DOI
12. European Medicines Agency. Ozempic (semaglutyd) - charakterystyka produktu leczniczego (summary of product characteristics). ema.europa.eu