Tirzepatide

Fat LossFDA-approved dual incretin agonistEstablished

Also known as: Mounjaro, Zepbound, LY3298176, Dual GIP/GLP-1 agonist

Tirzepatide (also called Mounjaro or Zepbound) is an FDA-approved dual incretin agonist in the GLP-1 Agonist class. Tirzepatide is a single thirty-nine-amino-acid peptide that activates both the GIP and GLP-1 receptors, with an acyl chain supporting albumin binding and weekly dosing.

Calculate Dose

For research use only.

Key Facts

CAS: 2023788-19-2
Molecular Weight (MW): ≈4813 g/mol
Half-life: Approximately 5 days
FDA status: Approved
Evidence level: FDA Approved
Human dose established: Yes
Administration Route: Subcutaneous
Frequency: Once weekly
Last updated: Sep 26, 2026
Reviewed: Aug 30, 2026
Targets: GIP receptorGLP-1 receptor

Vendor price snapshot

Each vendor counts once, at the median price per mg of its own listings; the typical range is the middle half of vendors. From public vendor listings collected between Dec 2025 and Sep 2026, so confirm the live price on the vendor site. Peptide Library does not sell peptides.

Vendors listing this peptide: 29
Listed offers: 123
Median price per mg: $7.33/mg; Typical $5.00–$9.33/mg

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Research summary

FDA-approved weekly dual GIP/GLP-1 receptor agonist for type 2 diabetes (Mounjaro) and obesity (Zepbound). Typical titration 2.5→15 mg. Not WADA-prohibited (monitoring).

Peptide Library's Tirzepatide profile summarises 5 cited studies listed in the Science section, the compound's regulatory status, and research-protocol parameters reported for it. It is a research reference, not medical advice.

Tirzepatide dosage chart

Tirzepatide has an FDA-approved human dosage. Both approved products start at 2.5 mg subcutaneously once weekly for 4 weeks and escalate in 2.5 mg steps at intervals of at least 4 weeks: Zepbound to a maintenance dose of 5, 10 or 15 mg once weekly, and Mounjaro to a maximum of 15 mg once weekly for type 2 diabetes.

FDA Approved

Dosage evidence summary for Tirzepatide
Human dosing established	Yes
Studied dose range	2.5–15 mg once weekly
Route	Subcutaneous
Frequency	Once weekly
Duration studied	Continuous; long-term for weight maintenance
Titration	2.5 mg once weekly for 4 weeks, then 5 mg once weekly. Further increases in 2.5 mg increments after at least 4 weeks at the current dose.
Half-life	Approximately 5 days
Evidence level	FDA Approved
Last reviewed	2026-09-05

Research-reported dosing

Doses as studied, one row per regimen. Different trials used different regimens; they are listed separately rather than averaged.

Research-reported dosing for Tirzepatide, one row per studied regimen
Study / context	Population	Dose	Route	Frequency	Duration	Outcome studied	Source
FDA label — Zepbound, weight reductionFDA-approved label · FDA prescribing information	Adults with obesity, or overweight with at least one weight-related comorbid condition	5 mg, 10 mg or 15 mg maintenance; 2.5 mg starting dose	Subcutaneous	Once weekly	Long term	Reduction and maintenance of body weight	ZEPBOUND (tirzepatide) injection — FDA prescribing information, DailyMed
FDA label — Zepbound, obstructive sleep apnoeaFDA-approved label · FDA prescribing information	Adults with obesity and moderate-to-severe obstructive sleep apnoea	10 mg or 15 mg	Subcutaneous	Once weekly	Long term	Moderate to severe obstructive sleep apnoea	ZEPBOUND (tirzepatide) injection — FDA prescribing information, DailyMed
FDA label — Mounjaro, type 2 diabetesFDA-approved label · FDA prescribing information	Adults with type 2 diabetes mellitus	2.5 mg starting dose, escalated in 2.5 mg steps to a maximum of 15 mg	Subcutaneous	Once weekly	Continuous	Glycaemic control	MOUNJARO (tirzepatide) injection — FDA prescribing information, DailyMed
SURPASS-2 — phase 3 head-to-head against semaglutideClinical trial · Phase 3 open-label randomised controlled trial	Adults with type 2 diabetes on metformin (n=1879)	5 mg, 10 mg or 15 mg	Subcutaneous	Once weekly	40 weeks	Change in glycated haemoglobin versus semaglutide 1 mg	Frías JP et al. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes. N Engl J Med. 2021.

Where sources disagree

The 2.5 mg dose is an escalation step in both labels and is explicitly not a maintenance dose. It is sometimes presented elsewhere as a standalone low-dose protocol, which the labelling does not support.
Maximum dose is 15 mg once weekly for both approved products. Higher weekly doses occasionally quoted in non-clinical sources exceed every approved regimen and every published phase 3 arm.

Reconstitution

Common research vial sizes: 5 mg, 10 mg, 15 mg, 30 mg.

Reconstitution arithmetic for Tirzepatide
Vial	Bacteriostatic water	Concentration	Per 0.01 mL
10 mg	2 mL	5 mg/mL	50 mcg per 0.01 mL
30 mg	3 mL	10 mg/mL	100 mcg per 0.01 mL

These figures are arithmetic only — they convert a vial and a volume into a concentration. They are not a recommendation to take any dose.

Calculate reconstitution & dose →

Handling & administration

Reconstitution Guide: Prefilled pen - no reconstitution needed
Injection Sites: AbdomenThighUpper arm
Concentration Example: Pre-filled pen: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, or 15 mg per dose
Timing Notes: Inject subcutaneously once weekly, same day each week, with or without food
Expected Onset: Weight loss effects typically seen within 4-8 weeks

Sequence & molecular data

Sequence and molecular data for Tirzepatide
Molecular formula	C225H348N48O68
Molecular weight	≈4813 g/mol
CAS number	2023788-19-2
Half-life	~5 days
Appearance	White to off-white powder (API)
Formulation	Prefilled Pen
PubChem CID	166567236

Identifiers link to the public PubChem, FDA Substance Registration (UNII), ChEMBL and DrugBank records for the same entity.

Science

Mechanism of Action

Tirzepatide is a single thirty-nine-amino-acid peptide that activates both the GIP and GLP-1 receptors, with an acyl chain supporting albumin binding and weekly dosing. Its agonism is deliberately imbalanced: it engages GIPR with affinity comparable to native GIP but GLP-1R considerably more weakly than native GLP-1, and it shows biased signalling at GLP-1R with reduced beta-arrestin recruitment, which limits receptor desensitisation. GLP-1 receptor activation contributes glucose-dependent insulin secretion, glucagon suppression and central appetite reduction; the added GIP component is thought to act on adipose tissue metabolism and on hindbrain circuits, and is the presumed reason head-to-head obesity trials show greater mean weight reduction than semaglutide.

Origin

Synthetic 39-aa dual incretin peptide.

Targets

GIP receptorGLP-1 receptor

Studies

Regulatory & research status

Tirzepatide is an FDA-approved product for specific labelled indications. Approval does not extend to the research contexts described on this page, and approved products are prescription medicines.

Regulatory and research status for Tirzepatide
FDA status	Approved
Availability	Prescription-Only
WADA (sport)	Permitted
Library classification	FDA-Approved

Benefits

Superior weight loss compared to semaglutide (up to 22.5% body weight)Excellent glycemic control in type 2 diabetesReduced cardiovascular riskImproved blood pressureBetter lipid profile

Tirzepatide side effects

The effects below are drawn from Tirzepatide's prescribing information, which lists the full adverse-reaction data.

Side Effects

Nausea
Vomiting
Diarrhea
Constipation
Abdominal pain
Decreased appetite
Gastroesophageal reflux
Injection site reactions
Pancreatitis (rare)

Contraindications

MTC / MEN2 personal or family history
Serious hypersensitivity

Storage & stability

Lyophilized (freeze-dried) peptide powder is far more stable than the reconstituted solution. Keep sealed vials cold, dry and away from light; long-term storage is typically frozen, with short-term refrigeration for vials in use.

Once reconstituted in bacteriostatic water, keep the solution refrigerated, avoid repeated freeze–thaw cycles and agitation, and label the vial with the reconstitution date and concentration. Discard any solution that turns cloudy or shows particulates.

Degradation rates differ by sequence: peptides containing methionine, cysteine, asparagine or glutamine are more prone to oxidation and deamidation, so shelf life after reconstitution is compound-specific rather than universal.

Read the full guide: how to store peptides before and after reconstitution →

Source: Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Stability of protein pharmaceuticals: an update. Pharm Res. 2010;27(4):544–575. (PMID 20143256). General guidance for research handling; not product-specific instructions.

Tirzepatide: frequently asked questions

What is Tirzepatide?

FDA-approved weekly dual GIP/GLP-1 receptor agonist for type 2 diabetes (Mounjaro) and obesity (Zepbound). Typical titration 2.5→15 mg. Not WADA-prohibited (monitoring). Tirzepatide is a single thirty-nine-amino-acid peptide that activates both the GIP and GLP-1 receptors, with an acyl chain supporting albumin binding and weekly dosing. Its agonism is deliberately imbalanced: it engages GIPR with affinity comparable to native GIP but GLP-1R considerably more weakly than native GLP-1, and it shows biased signalling at GLP-1R with reduced beta-arrestin recruitment, which limits receptor desensitisation.

What are the side effects of Tirzepatide?

Side effects recorded for Tirzepatide from its prescribing information include nausea, vomiting, diarrhea, constipation, abdominal pain, decreased appetite, gastroesophageal reflux, injection site reactions and pancreatitis (rare). Cautions recorded on this profile: MTC / MEN2 personal or family history and serious hypersensitivity. Research-grade vials sold online are not the licensed product. This is reference information, not medical advice.

How does Tirzepatide work?

Is Tirzepatide FDA approved?

Yes. Tirzepatide is approved by the FDA, and approved products are prescription medicines. Approval is always for specific indications studied in clinical trials, so an approved status does not mean the compound is approved for every use it is discussed for. Research-chemical material sold under the same name is not the approved product.

What is the half-life of Tirzepatide?

Reported half-life for Tirzepatide is ~5 days. Half-life describes how long the compound persists in circulation, not how long any effect lasts, and published figures vary with route of administration, formulation and the population studied.

Is Tirzepatide banned in sport?

Tirzepatide is recorded here as permitted in sport. Anti-doping status is revised annually, so athletes subject to testing should confirm against the current WADA Prohibited List before use.

What peptides are similar to Tirzepatide?

Compounds most often compared with Tirzepatide include Semaglutide, Retatrutide, Liraglutide and Exenatide. They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ.

How long does Tirzepatide take to show effects in research protocols?

The research protocol on this profile lists an expected onset of weight loss effects typically seen within 4-8 weeks. This is a protocol note describing when studies and researchers report observing changes, not a measured clinical outcome, and it varies with the model, dose and endpoint studied.

Where is Tirzepatide administered in research protocols?

Research protocols on this profile use subcutaneous administration, with recorded sites including abdomen, thigh, upper arm. Site rotation and sterile technique are standard practice in the research literature; this describes protocol conditions and is not guidance for use.

References

Related research, comparisons & guides

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Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Sep 26, 2026 · Version 6

This Tirzepatide profile is compiled from published literature (5 cited studies linked above), public regulatory records and chemical registries. It describes what research reports; it is not medical advice, and nothing here is a dosing recommendation for humans. Peptide Library does not sell peptides. Editorial policy · How profiles are compiled · Report an error

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