Source: https://peakpeptides.com/peptides/tirzepatide/ Peptide library · Metabolic # Tirzepatide A synthetic peptide that activates both GIP and GLP-1 receptors. Compounded tirzepatide is not FDA-approved, although FDA-approved versions exist and have been studied in large controlled human trials. Last reviewed September 22, 2026 At a glance - **Also called:** LY3298176; dual GIP/GLP-1 receptor agonist - **What it is:** A synthetic dual-incretin peptide - **Evidence:** Cells, mice and large controlled human trials - **Compounded preparation:** Not FDA-approved; separate approved products exist - **In sport:** Not named on the 2026 WADA Prohibited List - **At Promise Peptides:** Listed; currently waitlist-only The short version Tirzepatide is a lab-made chain of 39 amino acids designed to signal through two incretin receptors, GIP and GLP-1. Its evidence base is unusual for this library: it includes receptor and mouse experiments, early human pharmacology, and large randomized trials in adults with metabolic disease or obesity. FDA-approved versions exist, but compounded tirzepatide is not FDA-approved. Whether a compounded preparation has a place in someone’s care is a decision for a licensed provider based on that person’s medical needs. ## What it is Tirzepatide is a synthetic incretin-mimetic peptide. It is built from the backbone of glucose-dependent insulinotropic polypeptide, or GIP, and engineered to activate both the GIP receptor and the glucagon-like peptide-1 receptor. A fatty-acid side chain helps it bind albumin in the blood. It is not a naturally circulating human peptide, although the two hormone systems it copies are part of normal gut signaling. Researchers first called it LY3298176. It has 39 amino acids, a molecular formula of C225H348N48O68, a molecular weight of 4,813.53 daltons and CAS number 2023788-19-2. The discovery paper described its receptor activity in cells, findings in mice and an early human program involving 142 participants.[1] ## Where the research stands Tirzepatide has laboratory, animal and extensive human evidence. The controlled trials establish findings for the FDA-approved drug products and the populations studied. They do not establish that a compounded preparation is identical in quality, stability or clinical performance. How far the evidence has climbed 1. Cell studies · Yes · Receptor signaling and pancreatic-islet experiments 2. Animal studies · Yes · Metabolic research in mice 3. Small human pilots · Yes · Early pharmacology and proof-of-concept studies 4. Controlled human trials · Yes · Large randomized phase 3 programs 5. Compounded preparation · Not approved · Separate FDA-approved products exist Here is what some of the most-cited studies looked at. Each names its species, because a result in a mouse is not a result in a person. - **From discovery to first human studies** (Cells · Mice · Humans · 2018): The paper reported receptor assays, mouse measurements of glucose and food intake, and early studies involving 142 healthy adults and adults with type 2 diabetes. It did not test a compounded preparation.[1] - **Two receptors, uneven signaling** (Cells · 2020): Receptor and mouse-islet experiments compared engagement of the GIP and GLP-1 receptors and measured their signaling patterns. They did not test patient outcomes or a compounded preparation.[2] - **Gastric-emptying pharmacology** (Humans · 2020): A phase 1 study measured gastric emptying during treatment with an investigational tirzepatide trial product. It did not test a compounded preparation.[3] - **Type 2 diabetes trial** (Humans · 2021): An open-label randomized trial enrolled 1,879 adults with type 2 diabetes and measured glycated hemoglobin, body weight and adverse events. It tested manufactured trial products, not compounded tirzepatide.[4] - **Obesity trial** (Humans · 2022): A double-blind randomized trial enrolled 2,539 adults without diabetes who had obesity, or overweight with a weight-related condition. It measured body-weight change and adverse events against placebo and did not test compounded tirzepatide.[5] - **Pooled safety signals** (Review · 2023): A meta-analysis combined nine randomized trials covering 9,871 people and compared pancreatitis and gallbladder or biliary events. It summarized trial products, not compounded preparations.[6] ## What the research can’t tell you - **Approved and compounded are different**: The trials studied manufactured drug products, not every compounded preparation. They cannot verify the identity, stability or quality of a particular compounded vial. - **Common tolerability limits**: Across the controlled program, gastrointestinal events were common and sometimes led participants to stop treatment.[4][5] - **A rodent thyroid finding**: The FDA label carries a boxed warning based on thyroid C-cell tumors in rodents. Whether that finding predicts the same risk in humans is unknown.[7] - **Specific safety questions remain**: Gallbladder and biliary events appear as a pooled signal, while the pancreatitis estimate remains imprecise. A meta-analysis cannot settle every rare or long-term risk.[6] ## Compounded tirzepatide and FDA status FDA-approved versions exist; compounded tirzepatide is not FDA-approved FDA-approved tirzepatide products exist. Compounded tirzepatide is a different regulatory category: FDA does not review a compounded drug’s safety, effectiveness or quality before it is marketed.[8] FDA confirmed the national tirzepatide injection shortage was resolved on December 19, 2024.[9] FDA says section 503A restricts compounding drugs that are essentially copies of commercially available products regularly or in inordinate amounts; section 503B has a separate framework.[10] Those regulatory facts do not turn approved-product evidence into evidence for a compounded preparation. Promise Peptides is currently taking waitlist sign-ups. Joining is not a medical request and no prescription comes from it. ## A prescription route Promise is currently accepting waitlist signups. Joining is not a treatment request and does not result in a prescription. If treatment visits open, any treatment request would require clinical review; prescribing and pharmacy fulfillment would remain separate decisions. 1. **Start on Promise’s tirzepatide page**: It shows what the treatment involves and its current availability. 2. **Answer the tirzepatide questionnaire**: A licensed provider reviews health history, medicines and goals, and can decline. Not everyone qualifies. 3. **Pharmacy review is a separate step**: A prescription does not guarantee preparation or dispensing. A pharmacy must separately determine whether it can fulfill the prescription under the applicable requirements. A prescription does not turn compounded tirzepatide into an FDA-approved product; it means a clinician reviewed the individual case and made the prescribing decision. Tirzepatide at Promise Read the treatment information and view the current waitlist. [Join the Promise waitlist](https://mypromise.com/products/tirzepatide?utm_source=peak&utm_medium=affiliate&utm_campaign=library&utm_content=tirzepatide) Peak may earn money when readers become Promise patients. Joining does not guarantee future treatment availability. Availability would depend on the treatment, state, clinical review and separate pharmacy review. ## Questions ### Is tirzepatide a peptide? Yes. It is a synthetic chain of 39 amino acids with a fatty-acid side chain. Its design is based on the GIP hormone backbone.[1] ### Is tirzepatide a GLP-1? It is a GLP-1 receptor agonist, but not only that. It also activates the GIP receptor, which is why researchers call it a dual incretin agonist.[2] ### Is compounded tirzepatide FDA-approved? No. FDA-approved versions exist, but a compounded preparation does not carry FDA approval and is not reviewed by FDA before marketing.[8] ## Sources 1. Coskun T, et al. LY3298176, a novel dual GIP and GLP-1 receptor agonist for the treatment of type 2 diabetes mellitus: from discovery to clinical proof of concept. *Mol Metab*. 2018. [PubMed 30473097](https://pubmed.ncbi.nlm.nih.gov/30473097/) 2. Willard FS, et al. Tirzepatide is an imbalanced and biased dual GIP and GLP-1 receptor agonist. *JCI Insight*. 2020. [PubMed 32730231](https://pubmed.ncbi.nlm.nih.gov/32730231/) 3. Urva S, et al. The novel dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist tirzepatide transiently delays gastric emptying. *Diabetes Obes Metab*. 2020. [PubMed 32519795](https://pubmed.ncbi.nlm.nih.gov/32519795/) 4. Frias JP, et al. Tirzepatide versus semaglutide once weekly in patients with type 2 diabetes. *N Engl J Med*. 2021. [PubMed 34170647](https://pubmed.ncbi.nlm.nih.gov/34170647/) 5. Jastreboff AM, et al. Tirzepatide once weekly for the treatment of obesity. *N Engl J Med*. 2022. [PubMed 35658024](https://pubmed.ncbi.nlm.nih.gov/35658024/) 6. Zeng Q, et al. Safety issues of tirzepatide in type 2 diabetes and obesity: a systematic review and meta-analysis. *Front Endocrinol*. 2023. [PubMed 37908750](https://pubmed.ncbi.nlm.nih.gov/37908750/) 7. U.S. Food and Drug Administration. [Tirzepatide injection prescribing information](https://www.accessdata.fda.gov/drugsatfda_docs/label/2022/215866s000lbl.pdf). 2022. 8. U.S. Food and Drug Administration. [Compounding and the FDA: Questions and Answers](https://www.fda.gov/drugs/human-drug-compounding/compounding-and-fda-questions-and-answers). Content current as of September 16, 2025. 9. U.S. Food and Drug Administration. [Declaratory Order: Resolution of Shortages of Tirzepatide Injection Products](https://www.fda.gov/media/184606/download). December 19, 2024. 10. U.S. Food and Drug Administration. [Compounding when drugs are on FDA’s drug shortages list](https://www.fda.gov/drugs/human-drug-compounding/compounding-when-drugs-are-fdas-drug-shortages-list). ## Also in the library - [Semaglutide](https://peakpeptides.com/peptides/semaglutide/) (Metabolic) - [MOTS-c](https://peakpeptides.com/peptides/mots-c/) (Mitochondrial peptide) - [NAD+](https://peakpeptides.com/peptides/nad-plus/) (Coenzyme) - [Sermorelin](https://peakpeptides.com/peptides/sermorelin/) (Growth hormone) --- Peak maps the terrain; it does not examine anyone, so nothing here is medical advice, and the decision about any treatment belongs to a licensed provider who has reviewed your health. Peak may earn money when readers become Promise patients. Peak is not affiliated with any company called Peak Peptides or Peak Performance Peptides.