Tirzepatide Results by Week: SURMOUNT Timeline, Dose by Dose
In SURMOUNT-1, people on tirzepatide 15 mg weekly lost 20.9% of their body weight on average over 72 weeks, against 3.1% on placebo.
- Average loss, top dose
- 20.9%
- On placebo
- 3.1%
- Trial length
- 72 weeks
- Trial
- SURMOUNT-1
Zepbound: key facts
The half-life ranges from 5 to 6 days. At 5.5 d, half is gone. About 3% remains after five half-lives (27.5 d).
SURMOUNT-1 reported 20.9% of body weight after 72 weeks, compared with 3.1% among people receiving placebo.
Monthly prices in US dollars include the list price and self-pay offers, each taken from the manufacturer's price page.
Sources: FDA label (DailyMed), Eli Lilly 1 2, cnbc.com.
Tirzepatide results: the numbers first
| Trial | Dose group | Average weight lost | Placebo or comparison | Weeks | Who was in it |
|---|---|---|---|---|---|
| SURMOUNT-1 | Tirzepatide 5 mg weekly | 15% | 3.1% | 72 | Adults with obesity or overweight, without diabetes |
| SURMOUNT-1 | Tirzepatide 10 mg weekly | 19.5% | 3.1% | 72 | 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 10 mg weekly | 12.8% | 3.2% | 72 | Adults who have obesity or overweight and type 2 diabetes |
| SURMOUNT-2 | Tirzepatide 15 mg weekly | 14.7% | 3.2% | 72 | Adults who have obesity or overweight and type 2 diabetes |
| SURMOUNT-5 | Tirzepatide 10 or 15 mg weekly (Zepbound) | 20.2% | semaglutide (Wegovy) | 72 | Adults with obesity, without type 2 diabetes |
Sources: SURMOUNT-1 (FDA label (DailyMed)), SURMOUNT-2 (PubMed), SURMOUNT-5 (PubMed).
The average explained in pounds
For three different starting weights, the 20.9% trial average was applied. This is simple math, not a prediction for any one person. Some people 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 |
Sources: FDA label (DailyMed).
Week by week
- During the first weeks, stomach side effects occur most often as the dose stays low and increases. After each dose increase, they often come back for a few days.
- The average loss shown above comes from Week 72, when SURMOUNT-1 ended.
References: health.clevelandclinic.org and the FDA DailyMed label.
What causes it to stall and what helps
- See which dose step you are on. Each trial above shows less weight loss at the lower doses.
- Over the past month, count the doses missed and those taken late.
- For a few days, write down your food and drinks. As portion sizes get smaller, liquid calories and grazing add up.
- Discuss a blood sugar or thyroid check with your prescriber. If progress has stalled for months, ask them about switching medicines.