Reviewed by Dr. Jason Wright, D.O. · September 23, 2026
The science
How it works
GLP-1 receptor
The same pathway semaglutide uses: insulin released when blood sugar is high, slower stomach emptying, and fullness signaling in the hypothalamus.
GIP receptor in fat tissue
GIP receptors sit on fat cells. Activating them improves insulin sensitivity and how efficiently fat is stored and released, instead of spilling into the liver and muscle.
GIP receptor in the brain
GIP signaling adds appetite suppression and appears to blunt nausea, which is part of why patients tolerate higher doses than with a GLP-1 alone.
Two pathways together
Activating both receptors produced more weight loss than semaglutide in a head-to-head trial.
These effects are well established in large human trials of the FDA-approved medication.
Dosing
Your dosing plan
Dr. Wright sets your exact dose within this range at your visit.
Month 1
Form12 mg vial (6 mg/mL)
Dose2.5 mg (42 units)
ScheduleOnce weekly; step up only as tolerated
Based onFDA label schedule
Month 2
Form24 mg vial (12 mg/mL)
Dose5 mg (42 units)
ScheduleOnce weekly; step up only as tolerated
Based onFDA label schedule
Month 3
Form34 mg vial (17 mg/mL)
Dose7.5 mg (44 units)
ScheduleOnce weekly; step up only as tolerated
Based onFDA label schedule
Month 4
Form44 mg vial (22 mg/mL)
Dose10 mg (45 units)
ScheduleOnce weekly; step up only as tolerated
Based onFDA label schedule
Month 5
Form56 mg vial (28 mg/mL)
Dose12.5 mg (45 units)
ScheduleOnce weekly; step up only as tolerated
Based onFDA label schedule
Maximum
Form66 mg vial (33 mg/mL)
Dose15 mg (45 units)
ScheduleOnce weekly; step up only as tolerated
Based onFDA label schedule
Side effects
Side effects and what to expect
NauseaCommon · First weeks and after dose increases
Smaller meals, eat slowly, and hold the dose if needed.
Constipation or diarrheaCommon · First weeks
Fiber, fluids, and a steady routine.
Gallbladder symptomsUncommon · Any time
Pain under the right ribs after meals: let us know promptly.
Severe, ongoing belly painRare · Any time
Stop and go to the emergency room.
A note from Dr. Wright
Two pathways instead of one, and for many patients that’s the difference. The rule doesn’t change: steady loss that holds, with your muscle intact. I’d rather you lose 15% and keep it than 25% and spend a year getting it back.
Dr. Jason Wright, D.O. · Board certified, American Board of Cosmetic Surgery
Cost & access
Getting started with Tirzepatide
Tirzepatide
Tirzepatide with vitamin B12, 2 mL vials matched to your dose · Labeled in your name
In the main trial of the FDA-approved version, average loss was about 21% at the highest dose over 72 weeks. Results vary.
Tirzepatide or semaglutide?
In a head-to-head trial, tirzepatide produced more weight loss on average. Dr. Wright will help you choose based on your history and how you tolerate each.
Do I need lab work?
Yes. A metabolic panel, lipids, and A1c before you start, again at 3 months, then every 6 months.
What if I miss doses?
If you miss 2 or more weeks, you’ll restart 1 to 2 steps lower so your stomach can readjust.
Research
Supporting studies
Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1)
Jastreboff AM, et al. New England Journal of Medicine, 2022
