GLP-1 Weight Loss Timeline: See Month-by-Month Progress
Not how much, but when. Enter your details to project your weight, BMI, and body fat at every month on Ozempic, Wegovy, Mounjaro, or Zepbound — grounded in average clinical-trial results, with the 5%, 10%, 15% and 20% milestones marked along the way.
Average total body-weight loss is about 15% on Wegovy and up to ~20% on Zepbound and Mounjaro over 12–18 months; lower-dose Ozempic averages less. Loss is fastest in the first 3–6 months and flattens toward a plateau — that slowdown is normal. Project your month-by-month trajectory below.
Just want a single total instead of a timeline? Use the GLP-1 Weight Loss Calculator to estimate your total loss and goal weight.
What this calculator measures
This tool projects a realistic average weight-loss trajectory for your chosen GLP-1 over 12 months, then translates that into estimated BMI and body fat at each milestone. It's modeled on published clinical-trial averages and adjusted for your dose, escalation speed, calorie deficit, and activity level.
How it works
The model
Weight loss follows a curve that falls quickly, then levels off:
- maxLoss — the average total body-weight loss at plateau for your drug and dose.
- k — how fast you approach it, nudged by escalation speed, diet, and exercise.
- BMI uses the standard formula (703 × lb ÷ inches²).
- Body fat is estimated from BMI, age, and sex (Deurenberg equation).
| Medication | Avg. total loss at plateau* |
|---|---|
| Zepbound / Mounjaro (tirzepatide) | ~18–22% |
| Wegovy (semaglutide 2.4 mg) | ~15% |
| Ozempic (semaglutide, diabetes doses) | ~6–8% |
| Rybelsus (oral semaglutide) | ~5–6% |
*Trial averages (STEP, SURMOUNT, SUSTAIN). Individual results vary widely.
Why it matters
Realistic expectations keep people on treatment. Many quit early because the scale slows around month 4–6 — exactly when the curve is supposed to flatten. Seeing the whole trajectory, and knowing a plateau is normal, helps you stay the course and focus on body composition rather than the scale alone.
How to improve your results
- Prioritize protein (roughly 0.7–1 g per pound of goal weight) to protect muscle while you lose fat.
- Add resistance training 2–3× a week — it preserves lean mass and metabolic rate.
- Reach your maintenance dose as tolerated; under-dosing caps results.
- Stay consistent — missed weeks flatten the curve.
- Track body fat and measurements, not just weight, so plateaus don't discourage you.
Real-life example
Clinical considerations
This is a statistical projection, not a promise. Real trajectories depend on genetics, starting metabolism, other medications, sleep, stress, and how you tolerate the drug. Some people lose far more or less than average, and a portion don't respond. Rapid loss can also reduce muscle and, in some, cause gallbladder or nutrition issues — reasons to lose weight under medical supervision.
Frequently asked questions
Related calculators
References
- Wilding JPH et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). N Engl J Med. 2021.
- Jastreboff AM et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). N Engl J Med. 2022.
- Deurenberg P et al. Body mass index as a measure of body fatness. Br J Nutr. 1991.
- U.S. Food & Drug Administration — prescribing information for Wegovy, Ozempic, Zepbound, Mounjaro.
Tool Information
July 28, 2026
Dr. Jaydeep Sanghani
Meet Akabari
Dr. Jaydeep Sanghani
MBBS, MD, DNB(Anaesth.), PDCC(CCM), DrNB(CCM)
AIIMS Bhubaneswar · AIIMS Rishikesh
Critical care specialist and anesthesiologist with advanced training from AIIMS. Reviews health calculators at Calqulate to ensure medical accuracy and evidence-based standards.