Tirzepatide Research Peptide: Structure, COA Data and Lab Handling
Tirzepatide is a 39-amino-acid synthetic peptide that activates both the GIP and GLP-1 receptors. Labs use it as a reference dual agonist in receptor-signaling assays and as a comparator when characterizing newer multi-receptor peptides. This page covers its structure, what a tirzepatide certificate of analysis should show, and how to handle the lyophilized powder, using FRO Peptides’ own published lot reports as the example.
Tirzepatide at a glance
| Class | Dual GIP / GLP-1 receptor agonist (research compound) |
|---|---|
| Length | 39 amino acids, C-terminal amide |
| Molecular formula | C225H348N48O68 |
| Molecular weight | ≈ 4,813.5 g/mol |
| CAS number | 2023788-19-2 |
| Key modifications | Aib (α-aminoisobutyric acid) at positions 2 and 13; C20 fatty diacid on Lys20 via a γGlu–2×OEG linker |
| Supplied as | Lyophilized white powder in sealed vials |
| FRO vial sizes | 10mg, 15mg, 20mg, 30mg |
| FRO tested purity | 99.75% (10mg lot QPVK-4R84) and 99.81% (30mg lot LUEZ-9MDW), HPLC |
How the molecule is built
Tirzepatide’s backbone is based on the native GIP sequence, engineered so the same chain also binds the GLP-1 receptor. Two substitutions with Aib, a non-natural amino acid, protect it from enzymatic cleavage. The defining feature is the C20 fatty diacid side chain attached at lysine 20. That lipid tail binds albumin, which is why tirzepatide is far more stable in biological matrices than an unmodified peptide of the same length.
For lab work this matters in two ways. First, the side chain is part of the molecule’s identity, so a sample missing it, or carrying a damaged one, is not tirzepatide even if the peptide backbone is intact. Second, the lipid portion makes the molecule more sensitive to repeated freeze-thaw cycles and aggressive mixing than a plain peptide.
Why labs use it
- Receptor co-activation studies. One molecule engages two receptors, so it is used to study how GIP and GLP-1 signaling interact when both are triggered at once.
- Assay validation. Its activity at each receptor is well characterized in the published literature, which makes it a standard positive control for confirming an assay can tell GIP activity apart from GLP-1 activity.
- Comparator work. It is the usual reference point when characterizing newer dual and triple agonists such as retatrutide.
How to read a tirzepatide certificate of analysis
A COA is only useful if you know what each line proves. Here is FRO’s 30mg report (lot LUEZ-9MDW, AccuMark Labs, published 09/07/2026) line by line:
| Test | Result | What it tells you |
|---|---|---|
| Identity | Tirzepatide, conforms | The main compound in the vial matches tirzepatide. |
| HPLC purity | 99.81% (spec > 98.0%) | Share of the sample that is the target peptide, measured by UV detection at 220 nm. The chromatogram shows one sharp main peak at about 7.1 minutes. |
| Quantity | 32.25 mg measured in a 30 mg vial | How much peptide is actually in the vial. Many COAs skip this line, but it is the one that catches underfilled vials. |
| Endotoxin (LAL) | Pass, ≤ 5.0 EU/mL | Bacterial endotoxin is below the limit. |
| Sterility screen (PCR) | Not detected, pass | No microbial DNA detected in the sample. |
The 10mg lot (QPVK-4R84) tested at 99.75% HPLC purity. Both full reports are free to open in the Tirzepatide COA library. Match the lot code on your vial to the report.
HPLC purity vs. structural confirmation
HPLC purity tells you how clean the sample is. It does not, on its own, prove every part of the structure is intact. For a lipidated peptide like tirzepatide, mass spectrometry is the method that confirms the full molecular weight, including the fatty acid side chain. FRO’s current tirzepatide reports cover identity, HPLC purity, measured quantity, endotoxin and sterility. FRO has additional third-party testing underway at Vanguard Laboratory, an ISO 17025 lab, and new results are added to the COA library as they come in.
Red flags on any supplier’s COA
- No lot code, or a lot code that doesn’t match the vial.
- No lab name, or a lab you can’t find.
- Purity with no chromatogram.
- No measured quantity, only the label claim.
- The same report reused across several products or years.
Storage and handling for research use
- Lyophilized powder: store frozen (−20 °C), sealed and protected from light. Let the vial reach room temperature before opening to avoid condensation.
- Reconstitution: add bacteriostatic water slowly down the vial wall and swirl gently. Don’t shake, because agitation can damage the lipidated side chain. Use the peptide reconstitution calculator to work out concentration for your protocol.
- After reconstitution: refrigerate at 2–8 °C, protect from light, and use within your protocol’s defined window.
- Avoid repeated freeze-thaw. If you need to store reconstituted material frozen, split it into single-use aliquots first.
Frequently asked questions
Does FRO Peptides publish a COA for tirzepatide?
Yes. Every tirzepatide lot FRO sells has a published certificate of analysis from AccuMark Labs, an independent lab, viewable by lot code in the COA library.
What purity is FRO’s tirzepatide?
The current lots tested at 99.75% (10mg) and 99.81% (30mg) by HPLC, against a specification of more than 98.0%.
Is there more tirzepatide in the vial than the label says?
The 30mg lot measured 32.25 mg, slightly above the label amount. You can check the measured quantity for each lot on its COA.
What is the difference between the vial sizes?
Only the quantity of peptide. The 10mg, 15mg, 20mg and 30mg vials contain the same compound.
Is tirzepatide from FRO for human use?
No. FRO sells tirzepatide strictly for laboratory and analytical research. It is not for human or veterinary use.
View Tirzepatide research peptide (10mg–30mg) →
Every lot ships with a published COA. Ships next business day, FedEx 2-Day.
For laboratory research use only. Not for human or veterinary use. Not a drug, food, or cosmetic under FDA regulations. Nothing on this page is medical advice.