GLP-1 Timeline: First Week to Month 12, Stage by Stage
SURMOUNT-1 ran 72 weeks. By the end, people on tirzepatide 15 mg weekly had lost 20.9% of their body weight on average, against 3.1% on placebo. Side effects are most common in the first weeks and after each dose increase.
- Average loss, top dose
- 20.9%
- On placebo
- 3.1%
- Trial length
- 72 weeks
- Trial
- SURMOUNT-1
Weight loss and half-life at a glance
Half-life means how many days your body needs to remove half a dose. Each FDA label lists this measure in section 12.3.
A percentage of body weight. Since the trials, doses and lengths differ, compare each one with its own placebo on its page.
GLP-1 timeline: the numbers first
The top dose listed for each GLP-1 comes from its main weight trial. Different trials enrolled different people.
| Trial | Dose group | Average weight lost | Placebo or comparison | Weeks | Who was in it |
|---|---|---|---|---|---|
| STEP 1 | Semaglutide 2.4 mg weekly | 14.9% | 2.4% | 68 | Adults with obesity or overweight, without diabetes |
| OASIS 4 | Wegovy pill 25 mg daily | 13.6% | 2.4% | 64 | Adults with obesity or overweight, without diabetes |
| SURMOUNT-1 | Tirzepatide 15 mg weekly | 20.9% | 3.1% | 72 | Adults with obesity or overweight, without diabetes |
| SURMOUNT-2 | Tirzepatide 15 mg weekly | 14.7% | 3.2% | 72 | Adults who had obesity or overweight, plus type 2 diabetes |
| SCALE Obesity and Prediabetes | Liraglutide 3.0 mg daily | 7.4% | 3% | 56 | Adults affected by obesity or overweight, with type 2 diabetes |
| ATTAIN-1 | Foundayo 17.2 mg daily | 11.1% | 2.1% | 72 | Adults with obesity or overweight, without diabetes |
| ATTAIN-2 | Foundayo 17.2 mg daily | 9.6% | 2.5% | 72 | Adults who had obesity or overweight, plus type 2 diabetes |
| STEP 2 | Semaglutide 2.4 mg weekly | 9.6% | 3.4% | 68 | Adults who had obesity or overweight, plus type 2 diabetes |
Sources: STEP 1 (FDA label (DailyMed)), SURMOUNT-1 (FDA label (DailyMed)), SURMOUNT-2 (PubMed), SCALE Obesity and Prediabetes (FDA label (DailyMed)), ATTAIN-1 (FDA label (DailyMed)), STEP 2 (PubMed)
How to read the average in pounds
Three starting weights are shown, with the 20.9% trial average applied to each. This is simple arithmetic, not a prediction about one person. Some lose more, while others lose less.
| Starting weight | Average loss on tirzepatide 15 mg weekly | Average loss on placebo |
|---|---|---|
| 180 lb | about 38 lb | about 6 lb |
| 220 lb | about 46 lb | about 7 lb |
| 260 lb | about 54 lb | about 8 lb |
Source: FDA label (DailyMed).
Week by week
- Stomach side effects show up most often in the first weeks, while the dose remains low and rises. After every dose increase, they often return for a few days.
- SURMOUNT-1 ended at Week 72, and the average loss shown above was measured during the trial.
Sources: health.clevelandclinic.org and FDA label (DailyMed).