GLP-1 Weight Loss Progress Calculator - Mounjaro & Wegovy Timeline Estimator

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

In the first month on Mounjaro (typically at the 2.5 mg starting dose), most people lose between 2-4 kg (4-9 lbs). This is roughly 2-4% of starting body weight. Weight loss accelerates as doses increase over subsequent months, with the greatest losses seen at the 10-15 mg maintenance doses.

Q: How long does it take for Mounjaro to work?

Most people notice appetite suppression within the first 1-2 weeks of starting Mounjaro. Measurable weight loss typically begins within the first 2-4 weeks. Visible changes to face and body shape usually appear after 2-3 months of consistent use.

Q: Does Wegovy work faster than Mounjaro?

No. While both medications begin working within the first few weeks, clinical trial data shows Mounjaro produces greater total weight loss (20-22% vs 15% of body weight) over similar timeframes. Both medications follow a gradual dose-escalation schedule that takes several months to reach the maintenance dose.

Q: What percentage of weight do you lose on Mounjaro?

In the SURMOUNT-1 clinical trial, participants on the highest dose of Mounjaro (15 mg) lost an average of 22.5% of their body weight over 72 weeks. At the 10 mg dose, average weight loss was 21.4%, and at 5 mg it was 15%. Individual results vary based on diet, exercise, and metabolic factors.

Q: Do you regain weight after stopping Mounjaro?

Research suggests that most people regain a significant portion of lost weight after discontinuing GLP-1 medications like Mounjaro. The SURMOUNT-4 trial showed that participants who switched from tirzepatide to placebo regained approximately two-thirds of their lost weight over 52 weeks. This is why many prescribers recommend long-term use or gradual tapering with lifestyle modifications.

Q: How long should you stay on Mounjaro?

There is no universally agreed-upon stopping point for Mounjaro. Many clinicians recommend remaining on the medication long-term, as weight regain is common after discontinuation. Some people may reduce to a lower maintenance dose once they reach their goal weight. This decision should be made with your prescriber based on your individual circumstances.

Q: Is Mounjaro or Wegovy better for weight loss?

Clinical trial data suggests Mounjaro (tirzepatide) produces greater average weight loss than Wegovy (semaglutide). Mounjaro's dual GIP/GLP-1 mechanism led to 20-22% body weight loss vs approximately 15% with Wegovy over similar trial durations. However, individual responses vary, and the best medication depends on your medical history, insurance coverage, and prescriber recommendation.

Wondering how much weight you can lose on Mounjaro, Wegovy, or Ozempic? This calculator estimates your expected weight loss timeline based on clinical trial data from the SURMOUNT and STEP trials, your starting weight, and your current dose. Enter your details below for a personalised projection of your GLP-1 weight loss journey.

Medication

Mounjaro Wegovy Ozempic

Start Date

Current Dose

Starting Weight

Current Weight (optional)

If you're already on medication, enter your weight today.

Goal Weight (optional)

Estimated Weight Lost (to date)

Weeks on Medication

% Body Weight Lost

Estimated Weeks to Goal

Estimated Current Weight

Face Slimming Phase

Body Composition Phase

Start

Week 0

Appetite Suppression

Week 1-2

First 5% Loss

Week 8-12

Face Changes Begin

Week 4-8

Body Contour Visible

Month 3-6

Goal Weight

This is an estimate based on clinical trial averages. Individual results vary significantly based on diet, exercise, metabolism, and adherence. Consult your prescriber for personalised medical advice.

Track your actual face and body changes in SKOR - the only app that scores your GLP-1 transformation

How Much Weight Can You Lose on Mounjaro?

Mounjaro (tirzepatide) is a dual GIP/GLP-1 receptor agonist that has shown the most impressive weight loss results of any currently approved medication. In the landmark SURMOUNT-1 clinical trial, participants without diabetes who received the highest dose (15 mg) lost an average of 22.5% of their body weight over 72 weeks. Even the lowest tested dose (5 mg) produced an average of 15% body weight reduction.

To put that in practical terms: a person starting at 100 kg on the maximum dose could expect to lose roughly 20-22 kg over 18 months. Weight loss is not linear, however. The first few weeks at the starting dose of 2.5 mg typically produce modest losses of 1-2 kg per month, with the rate accelerating significantly as doses are titrated upward every four weeks. Most people see their fastest rate of weight loss between months 3 and 9, with the curve beginning to plateau as they approach their final weight.

The SURMOUNT-2 trial in people with type 2 diabetes showed slightly lower but still remarkable results, with average weight loss of 14.7% at the 15 mg dose. These results established Mounjaro as the most effective weight loss medication currently available.

How Much Weight Can You Lose on Wegovy?

Wegovy (semaglutide 2.4 mg) is a GLP-1 receptor agonist that was the first medication in its class approved specifically for weight management. The STEP clinical trial programme demonstrated that participants on the maintenance dose of 2.4 mg lost an average of approximately 15% of their body weight over 68 weeks.

For a 100 kg person, this translates to roughly 15 kg of weight loss. Like Mounjaro, Wegovy follows a gradual dose-escalation schedule: starting at 0.25 mg weekly and increasing every four weeks to reach the full 2.4 mg dose over 16-20 weeks. Weight loss begins during the escalation phase and continues to accelerate once the maintenance dose is reached. Most participants in STEP trials achieved the bulk of their weight loss between weeks 12 and 52, with the rate slowing as they approached the 68-week mark.

Mounjaro vs Wegovy: Weight Loss Comparison

Both Mounjaro and Wegovy are effective GLP-1 medications for weight loss, but their clinical trial data reveals meaningful differences in efficacy, mechanism, and dose schedules.

Factor	Mounjaro (tirzepatide)	Wegovy (semaglutide)	Ozempic (semaglutide)
Mechanism	Dual GIP/GLP-1	GLP-1 only	GLP-1 only
Avg. weight loss	20-22% (max dose)	~15% (max dose)	~12% (max dose)
Trial duration	72 weeks (SURMOUNT)	68 weeks (STEP)	68 weeks (STEP)
Max dose	15 mg weekly	2.4 mg weekly	2 mg weekly
Dose escalation	5 dose levels	5 dose levels	4 dose levels
Primary approval	Weight loss + T2D	Weight loss	Type 2 diabetes

When Do You Start Seeing Results on GLP-1?

Understanding the typical timeline of GLP-1 weight loss helps set realistic expectations. Here is what most people experience at each stage:

Week 1-2: Appetite suppression begins. Most people notice reduced hunger and earlier satiety (feeling full faster). Scale weight may drop 0.5-1 kg due to reduced food intake.
Week 2-4: Consistent early weight loss. Food noise (constant thoughts about food) typically diminishes significantly. Some gastrointestinal side effects may occur as the body adjusts.
Week 4-8: Facial changes begin. As the first 3-5% of body weight comes off, face slimming becomes noticeable, particularly around the jawline, cheeks, and under the chin. This is often the first visible change others notice.
Month 2-4: Dose escalation continues and weight loss accelerates. Clothing begins to fit differently. The 5% body weight milestone is typically reached during this period.
Month 3-6: Pronounced facial changes and visible body contour improvements. This is when many people notice the most dramatic visual transformation. Body composition changes become clearly visible, particularly around the waist, hips, and upper arms.
Month 6-12: Weight loss continues at a gradually slowing rate. The 10-15% body weight loss milestone is typically reached. Skin may begin to adapt to the new body shape.
Month 12-18: Weight loss approaches its plateau. On Mounjaro, total losses of 20%+ are common at this stage. Body composition may continue to improve even as scale weight stabilises.

How GLP-1 Changes Your Face and Body Over Time

One of the most striking aspects of GLP-1 weight loss is how it changes your appearance beyond just the number on the scales. Understanding these visual changes helps you appreciate your progress and stay motivated through the journey.

Face slimming is typically the first visible change. Fat loss around the buccal fat pads (cheeks), submental area (under the chin), and along the jawline creates a more defined facial structure. Most people begin noticing these changes between weeks 4 and 8, with the most pronounced changes visible between months 3 and 6. This is why tracking your face over time with consistent selfies or a tool like SKOR reveals changes you might not notice day to day.

Body contour changes follow facial slimming and typically become visible from month 3 onward. Visceral fat (around the organs) is often the first to reduce, leading to measurable waist circumference changes even before the mirror shows dramatic differences. Subcutaneous fat loss in the arms, thighs, and hips becomes visible from months 4-6.

Skin quality can both improve and face challenges during rapid weight loss. Reduced inflammation from lower body weight and improved metabolic health often leads to clearer, brighter skin. However, skin laxity (loose skin) can become a concern with losses above 15-20% body weight, particularly for those over 40 or who have carried excess weight for many years.

SKOR tracks all of these dimensions - Face Slimming, Skin Quality, Body Composition, and more - giving you an objective, AI-powered score for each metric so you can see exactly what is changing week by week.

Frequently Asked Questions

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

In the first month on Mounjaro, most people lose between 2-4 kg (4-9 lbs), which is approximately 2-4% of starting body weight. This is typically at the 2.5 mg starting dose, where weight loss is modest. As the dose increases over subsequent months, monthly weight loss typically accelerates to 3-5 kg per month at higher doses. Over a full 18-month course, the average works out to roughly 1-1.5 kg per week.

How long does it take for Mounjaro to work?

Most people experience appetite suppression within the first 1-2 weeks of starting Mounjaro. Measurable weight loss on the scales typically begins within the first 2-4 weeks. Clinically significant weight loss (5% of body weight) is usually achieved within 12-16 weeks. The full effects of Mounjaro continue to develop over 12-18 months as the dose is escalated and sustained at maintenance levels.

Does Wegovy work faster than Mounjaro?

No. Both medications begin working within the first few weeks, but Mounjaro generally produces more weight loss over the same timeframe. In clinical trials, Mounjaro users lost 20-22% of body weight over 72 weeks compared to approximately 15% with Wegovy over 68 weeks. Both drugs follow a gradual dose-escalation schedule, and neither produces dramatically faster initial results than the other.

What percentage of weight do you lose on Mounjaro?

In the SURMOUNT-1 trial, average weight loss percentages by dose were: 5 mg - 15%, 10 mg - 21.4%, and 15 mg - 22.5% of body weight over 72 weeks. The placebo group lost approximately 3.1%. These are averages, and individual results ranged from as little as 5% to over 30% in some participants. Factors including starting weight, diet, exercise, and metabolic health all influence individual outcomes.

When does Mounjaro start working for weight loss?

Mounjaro begins reducing appetite within the first week for most people. The medication works by mimicking natural hormones (GLP-1 and GIP) that regulate hunger and blood sugar. Most people notice reduced food cravings and earlier satiety within 7-14 days. Scale weight typically begins to drop within 2-4 weeks. However, the starting dose of 2.5 mg is intentionally low to minimise side effects, so significant weight loss usually begins once the dose is increased.

How much weight can I lose on Wegovy in 3 months?

In clinical trials, participants on Wegovy lost approximately 6-8% of their starting body weight in the first 3 months. For a person weighing 100 kg, this is roughly 6-8 kg (13-18 lbs). During this period, the dose is still being escalated from 0.25 mg toward the full 2.4 mg maintenance dose, so weight loss is still accelerating. The most rapid weight loss phase typically occurs between months 3 and 9.

What is the average weight loss per week on Mounjaro?

Based on SURMOUNT trial data, average weight loss on Mounjaro works out to approximately 0.5-1 kg (1-2 lbs) per week over the full 72-week treatment period. However, the rate is not constant: weight loss is slower in the first month at the 2.5 mg starting dose (perhaps 0.3-0.5 kg/week) and faster during months 3-9 at higher doses (potentially 0.8-1.5 kg/week). The rate gradually slows as participants approach their weight loss plateau.

Do you regain weight after stopping Mounjaro?

Unfortunately, research indicates that most people regain a significant portion of lost weight after discontinuing GLP-1 medications. The SURMOUNT-4 trial found that participants who switched from tirzepatide to placebo regained approximately two-thirds of their lost weight over 52 weeks. This underscores the chronic nature of obesity as a condition and is why many clinicians recommend long-term medication use, combined with sustainable lifestyle changes to minimise regain if the medication is eventually stopped.

How long should you stay on Mounjaro?

There is no universally agreed-upon stopping point. Current evidence suggests that long-term use provides the best weight maintenance outcomes. Some prescribers recommend staying on the medication indefinitely, potentially at a reduced maintenance dose. Others suggest a trial of discontinuation once goal weight is reached, with close monitoring for weight regain. The decision should be made in consultation with your prescriber, taking into account your individual medical history, weight loss goals, and risk factors.

Is Mounjaro or Wegovy better for weight loss?

Based on clinical trial data, Mounjaro (tirzepatide) produces greater average weight loss than Wegovy (semaglutide). Mounjaro's dual GIP/GLP-1 mechanism led to 20-22% body weight loss versus approximately 15% with Wegovy over similar trial durations. However, the best medication for any individual depends on several factors: medical history, insurance coverage and cost, availability, side effect profile, and prescriber recommendation. Some people respond better to one medication than the other, so what works best on average may not be what works best for you.

Last updated: 22 March 2026