Tirzepatide
The best-studied compound in this library. FDA approved for type 2 diabetes (2022) and chronic weight management (2023).
Quick chart
Change these and every table below updates.
Dosing schedules (as studied)
Both schedules follow the FDA label: start at 2.5 mg for 4 weeks, then increase by 2.5 mg no sooner than every 4 weeks. They match the 5 mg and 15 mg groups of the 72-week SURMOUNT-1 trial. Prescribers can hold a step longer if side effects occur.
Lower maintenance
5 mg groupOne step-up, then 5 mg weekly, the lowest maintenance dose on the label.
| Phase | Weeks | Weekly dose | Syringe units | Volume | Doses per vial* |
|---|---|---|---|---|---|
| Start | 1–4 | 2.5 mg | 12.5 | 0.125 mL | 4 |
| Maintenance | 5–72 | 5 mg | 25 | 0.25 mL | 4 |
* Limited by the vial's contents or the 28-day use limit after mixing, whichever comes first.
Average weight change at 72 weeks in SURMOUNT-1: −15.0%.
- 18 × 60 mg vials (each vial is used for at most 28 days after mixing)
- 54 mL bacteriostatic water (3 mL per vial)
- 72 × 0.3 mL (30-unit) U-100 insulin syringes
- 162 alcohol prep pads, plus a sharps container
Full step-up
15 mg groupSteps up by 2.5 mg every 4 weeks to the label maximum of 15 mg, reached at week 21.
| Phase | Weeks | Weekly dose | Syringe units | Volume | Doses per vial* |
|---|---|---|---|---|---|
| Start | 1–4 | 2.5 mg | 12.5 | 0.125 mL | 4 |
| Step 2 | 5–8 | 5 mg | 25 | 0.25 mL | 4 |
| Step 3 | 9–12 | 7.5 mg | 37.5 | 0.375 mL | 4 |
| Step 4 | 13–16 | 10 mg | 50 | 0.5 mL | 4 |
| Step 5 | 17–20 | 12.5 mg | 62.5 | 0.625 mL | 4 |
| Maintenance | 21–72 | 15 mg | 75 | 0.75 mL | 4 |
* Limited by the vial's contents or the 28-day use limit after mixing, whichever comes first.
Average weight change at 72 weeks in SURMOUNT-1: −20.9%. The 10 mg group (−19.5%) followed this path and stopped at 10 mg from week 13.
- 18 × 60 mg vials (each vial is used for at most 28 days after mixing)
- 54 mL bacteriostatic water (3 mL per vial)
- 72 × 1 mL (100-unit) U-100 insulin syringes
- 162 alcohol prep pads, plus a sharps container
Reconstitution for this setup
- Let the 60 mg vial reach room temperature and wipe both stoppers with alcohol.
- Slowly add 3 mL of bacteriostatic water, aiming down the inside wall of the vial.
- Swirl gently until clear. Never shake.
- Label the vial: 20 mg/mL, with today's date. Refrigerate and use within 28 days.
Trial results by group
| Trial group | Maintenance dose | Weight change at 72 weeks |
|---|---|---|
| 5 mg | 5 mg weekly | −15.0% |
| 10 mg | 10 mg weekly | −19.5% |
| 15 mg | 15 mg weekly | −20.9% |
| Placebo | — | −3.1% |
- Results use the trial's treatment-regimen analysis. Among participants who stayed on treatment, weight loss was 16.0%, 21.4% and 22.5%.
- The label's maintenance doses are 5, 10 or 15 mg (10 or 15 mg for sleep apnea). The 2.5 mg dose is for starting treatment only.
- Most side effects were gastrointestinal and occurred mainly during step-ups.
Research summary
Tirzepatide activates two gut-hormone receptors (GIP and GLP-1) that regulate appetite, insulin release and digestion. It is taken as a once-weekly injection under a prescriber's care.
What the research shows
- In the SURMOUNT-1 trial (NEJM, 2022), adults without diabetes lost an average of about 15–21% of body weight over 72 weeks, depending on dose.
- Later trials studied effects on sleep apnea, heart failure and other weight-related conditions.
- The most common side effects are gastrointestinal: nausea, diarrhea and constipation, mostly while the dose is increasing.
How it's prescribed
The FDA label describes a gradual dose increase every four weeks to limit side effects. Your prescriber sets the schedule based on how you respond.
References
- Jastreboff AM, et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). N Engl J Med 2022. View source
- FDA prescribing information, Zepbound® (tirzepatide), via DailyMed. View source
Related compounds
Last reviewed: November 2026