Social media is full of dramatic before-and-after transformations. While these are real, they represent the best-case scenarios. Here's what the clinical data actually says about average results — plus what influences whether you'll be closer to the top or bottom of the range.
Average results by medication
| Medication | Avg. % lost | For a 100kg person | Timeframe | Top 33% lose |
|---|---|---|---|---|
| Mounjaro (15mg) | 22% | 22kg | 72 weeks | 25%+ |
| Wegovy (2.4mg) | 15% | 15kg | 68 weeks | 20%+ |
| Duromine | 7.5% | 7.5kg | 12 weeks | 10%+ |
| Contrave | 7.5% | 7.5kg | 56 weeks | 10%+ |
| Xenical | 4% | 4kg | 52 weeks | 5%+ |
What determines where you'll fall in the range?
Researchers have identified several factors that predict better or worse response to GLP-1 medications:
- Genetics: Up to 30% of treatment response may be genetically determined. This isn't something you can control — some people are simply better responders.
- Starting BMI: People with higher starting BMIs tend to lose a greater absolute amount of weight, though the percentage may be similar.
- Early response: Patients who lose 5%+ in the first 3–4 months tend to achieve the best overall results. Early response is a positive predictor.
- Dose tolerance: Reaching and maintaining the full therapeutic dose is critical. Patients who can't tolerate the highest dose have lower average results.
- Lifestyle factors: Diet quality (especially protein intake), exercise (especially resistance training), sleep quality, and stress management all influence results.
- Medication adherence: Missing even one dose per month meaningfully reduces effectiveness.
The realistic timeline
Weight loss on GLP-1 medications typically follows a predictable pattern:
- Months 1–2: Slow start during dose escalation. 1–3% loss. Don't judge results yet.
- Months 3–6: Rapid loss phase. This is when most dramatic changes occur. 5–12% total.
- Months 6–12: Continued loss but slowing. 10–18% total.
- Months 12–18: Approaching maximum. Weight stabilising. 14–22% total.
- Month 18+: Maintenance. Weight stable while on medication.
What the scale doesn't show
Body weight is only one metric. Patients on weight loss medication commonly report improvements that the scale doesn't capture: reduced waist circumference, better-fitting clothes, improved blood pressure, normalised blood sugar, better sleep, increased energy, improved mood, and reduced joint pain. Track these alongside your weight for a more complete picture of your progress.