Tirzepatide
/tir-ZEP-ah-tide/aka Mounjaro, Zepbound, LY3298176
Once-weekly dual agonist of the GIP and GLP-1 receptors. FDA-approved for type 2 diabetes, weight management and sleep apnea with obesity.
Tirzepatide: educational research discussion. Not medical advice. Not a protocol for you.Details
- Reported range
- 2.5–15 mg weekly
- Frequency
- Once weekly
- Cycle length
- Escalate every 4+ weeks, then continuous
- Half-life
- ≈ 5 days
- Route
- SC
Reported figures describe what is published or discussed. None of them is a dose for you.
Mechanism
What it is proposed to do
Tirzepatide is a 39-amino-acid peptide built on the GIP hormone backbone, with a fatty-acid chain that extends its half-life to about 5 days. It activates both GIP and GLP-1 receptors. The GLP-1 arm reduces appetite, slows stomach emptying and increases glucose-dependent insulin release. How much the GIP arm adds, and exactly how, is still debated.
- 01
Tirzepatide
39-aa peptide with a fatty-acid chain; ~5-day half-life
established - 02
GIP + GLP-1 receptors
One molecule, two incretin receptors
established - 03
Appetite ↓ · gastric emptying ↓ · insulin ↑
Insulin release is glucose-dependent
established - 04
Weight, glucose and apnea events ↓
Shown in SURPASS, SURMOUNT and SURMOUNT-OSA RCTs
established
Half-life. About 5 days per the label, which supports once-weekly dosing.
Dosing & cycles
What is reported, and where it comes from
Numbers below are labeled FDA label, clinical trial range or commonly reported range. They describe the published and discussed landscape. They are not instructions and not a protocol for you.
Dosing studio
Every figure is labeled by where it comes from.
Scale view: Zepbound label (weight reduction)
Probe at 8.75 mg: inside the reported band (2.5–15 mg). Drag it to read the scale. It does not pick a number for you.
Typical cycle, as a calendar
Zepbound label titration
Escalation over months, then continuous
The label pattern: 2.5 mg weekly to start, then 2.5 mg steps at least 4 weeks apart until a maintenance dose of 5, 10 or 15 mg. This chart runs all the way to 15 mg; the label allows maintenance at any of the three.
Cycle patterns
Zepbound label titration
The label pattern: 2.5 mg weekly to start, then 2.5 mg steps at least 4 weeks apart until a maintenance dose of 5, 10 or 15 mg. This chart runs all the way to 15 mg; the label allows maintenance at any of the three.
Stacks
What it gets combined with
Why people pair things, and what nobody has tested.
GLP + anything
3 compounds- Why people combine these
- People add repair or GH-axis peptides hoping to ease GI side effects or protect lean mass.
- Caution
- Tirzepatide is the only tested drug in the mix. No interaction data exist, and if something goes wrong there is no way to tell which compound caused it.
- What is unknown
- No published human data on this combination: dosing, interactions and long-term effects are all unstudied.
Tirzepatide + MOTS-c
2 compounds- Why people combine these
- Pitched as pairing appetite control with an "exercise mimetic" to protect muscle.
- Caution
- MOTS-c's muscle and metabolic effects come from mice. No study has tested the pair, and MOTS-c is WADA-prohibited.
- What is unknown
- No published human data on this combination: dosing, interactions and long-term effects are all unstudied.
Evidence
How much of this is known
Evidence grade
A
Strong human evidence
Multiple adequate human RCTs and/or FDA approval for a defined indication.
How we gradeGraded A on the strength of large RCTs and FDA approval for three indications. The evidence belongs to the approved product, not to compounded or gray-market copies.
Human trial status
SURMOUNT-1 (2,539 adults, 72 weeks): 15.0%, 19.5% and 20.9% mean weight loss on 5, 10 and 15 mg vs 3.1% on placebo. SURMOUNT-5 (751 adults, open-label, 72 weeks): 20.2% on tirzepatide vs 13.7% on semaglutide. SURMOUNT-OSA: apnea events fell by about 25 to 29 per hour vs about 5 on placebo at 52 weeks. SURMOUNT-4: stopping led to substantial regain.
Limitations
- Benefits depend on continued treatment. SURMOUNT-4 showed substantial regain after switching to placebo.
- SURMOUNT-5 was open-label, with both drugs at their maximum tolerated dose.
- Trials used the branded product. Compounded and gray-market versions were not tested.
Sources to read
- Jastreboff AM et al. Tirzepatide once weekly for the treatment of obesity, SURMOUNT-1 (NEJM 2022)
- Aronne LJ et al. Tirzepatide as compared with semaglutide for the treatment of obesity, SURMOUNT-5 (NEJM 2025)
- Aronne LJ et al. Continued treatment with tirzepatide for maintenance of weight reduction, SURMOUNT-4 (JAMA 2024)
- Malhotra A et al. Tirzepatide for the treatment of obstructive sleep apnea and obesity, SURMOUNT-OSA (NEJM 2024)
- ZEPBOUND prescribing information (DailyMed)
- MOUNJARO prescribing information (DailyMed)
Links open PubMed, DailyMed, FDA or trial-registry searches. We do not cite what we have not described accurately.
Safety
Side effects, cautions, status
Commonly reported effects
- GI effects dominate. Label rates: nausea 25–29%, diarrhea 19–23%, constipation 11–17%, vomiting 8–13%, mostly during dose escalation.
- Boxed warning: thyroid C-cell tumors in rats, human risk unknown. Contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2.
- Label warnings include pancreatitis, gallbladder disease, kidney injury from dehydration, hypoglycemia with insulin or sulfonylureas, hypersensitivity, diabetic retinopathy complications and aspiration risk under anesthesia.
- Oral contraceptives: the label advises switching to a non-oral method, or adding a barrier method, for 4 weeks after starting and 4 weeks after each dose increase.
- Weight regain after stopping: in SURMOUNT-4, people switched to placebo regained 14% of body weight over the next 52 weeks.
Who should be extra cautious
- Medullary thyroid cancer or MEN 2 history. Contraindicated (boxed warning).
- Oral contraceptive users. Pill absorption may fall after starting and after each dose increase. The label calls for a backup plan at those points.
- Pregnancy. The Zepbound label says weight loss is not recommended in pregnancy and advises stopping when pregnancy is recognized.
- Insulin or sulfonylurea users. Hypoglycemia risk rises in combination.
- Compounded or gray-market "tirz". Not the approved product, and not what SURMOUNT tested.
Legal & regulatory status
FDA-approved prescription drug, not a research peptide. Mounjaro (2022) treats type 2 diabetes. Zepbound (2023) is approved for chronic weight management and, since 2024, for moderate-to-severe obstructive sleep apnea in adults with obesity.
2026 compounding context. FDA declared the tirzepatide shortage resolved in December 2024. Mass compounding of copies is no longer permitted, and "personalized" compounded versions are legally contested. Compounded products were not tested in SURMOUNT.
WADA. Not on the WADA Prohibited List. From January 2026 WADA's Monitoring Program tracks tirzepatide alongside semaglutide (tracked, not banned). Confirm with your federation.
Storage & handling, high level
Pens and vials are refrigerated. The Mounjaro label allows single-dose pens and vials up to 21 days unrefrigerated at or below 30°C (86°F). Follow the label for the specific product, not a forum.
Reconstitution and injection technique are clinical skills. The reconstitution calculator does arithmetic only.
FAQ
Questions people ask about Tirzepatide
How is it different from semaglutide?
Why does the label mention birth control pills?
Is it a research peptide?
What happens after stopping?
Is it banned in sport?
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