FDA-approved
Tirzepatide
Two incretin signals in one weekly injection.
KEY EVIDENCE
SURMOUNT-1 · SURMOUNT-OSA
VIDEO LESSON
How it's taken
• Weekly injection by pen or single-dose vial
• Starts at 2.5 mg and rises by 2.5 mg about every 4 weeks as tolerated, up to 15 mg
Side effects at a glance
• Nausea, diarrhea, constipation and vomiting
• Injection-site reactions
Rare but serious
• Pancreatitis and gallbladder disease
• Same thyroid C-cell tumor warning as other incretin medicines
Monitoring
Weight, blood pressure, glucose and lipids. Use a backup or non-oral contraceptive for 4 weeks after starting and after each dose increase.
Good to know
In the head-to-head SURMOUNT-5 trial, tirzepatide produced greater weight loss than semaglutide at 72 weeks. It is also approved for moderate to severe sleep apnea in adults with obesity.
AT A GLANCE
Type
Medication
Brand names
Zepbound, Mounjaro
Status
FDA-approved
Reviewed by
Farhan Tahir, MD
Is this treatment right for you?
Prescription medicines and procedures need individual medical advice. Dr. Tahir’s team offers consults through Youthful Medicine.
How it works
A dual GIP and GLP-1 receptor agonist given once a week (Zepbound). Pairing the two signals produced larger average weight loss than GLP-1 alone in trials.
What the evidence shows
In SURMOUNT-1, the 15 mg dose produced a mean 20.9% weight loss at 72 weeks versus 3.1% on placebo. In December 2024 it became the first medicine FDA-approved for moderate-to-severe obstructive sleep apnea in adults with obesity.
Side effects & cautions
Gastrointestinal side effects are common. It carries the same thyroid C-cell tumor warning as other incretin medicines. It can make birth-control pills less reliable after starting and after each dose increase, so a backup method is advised.
PRIMARY SOURCE
Jastreboff AM et al. Tirzepatide once weekly for the treatment of obesity. N Engl J Med 2022;387:205–216.
TYPICAL RESULT IN TRIALS
≈21% mean weight loss at 72 weeks (15 mg)
PHYSICIAN FIRST
Is this right for you?
Prescription treatments need a review of your history, labs and other medicines. Never start or stop one on your own.