GLP-1 is glucagon-like peptide-1, an incretin peptide studied in receptor-signaling and metabolic research. The GLP-1 catalog entry corresponds to the GLP-1 (7-37) fragment: 31 amino acid residues, CAS number 106612-94-6, molecular formula C151H226N40O46, and a molecular weight of 3337.73 g/mol. It is supplied as a lyophilized powder for laboratory research only.
This FAQ answers the identity and specification questions researchers ask most often, then turns to the lane Upper Meadows works in: what happens to this peptide in storage, which degradation pathways matter, and how a stored lot is checked against its original documentation. GLP-1 is a useful case study because it is a comparatively short sequence with several chemically reactive positions, so its stability profile is a good illustration of general peptide behavior.
What do the catalog figures for GLP-1 actually mean?
Each figure on the record is a defined quantity. The CAS number 106612-94-6 is a registry identifier for the substance; it says nothing about quality. The formula C151H226N40O46 is the elemental composition of the intact 31-residue peptide. The molecular weight of 3337.73 g/mol is the theoretical mass that mass-spectrometry results are compared against. The purity line, 99%+ by HPLC, is a separate statement about the fraction of the main chromatographic peak under a stated method.
The numbering "7-37" matters. The full-length precursor is longer, and the biologically studied form is the fragment beginning at residue 7 and ending at residue 37, which gives 31 residues. A record that omits the fragment designation is ambiguous, because a different residue range would carry a different formula and mass. Reading the designation alongside the formula is the first check a careful reader makes.
Why is GLP-1 treated as a stability-sensitive peptide?
GLP-1 is stability-sensitive for two separate reasons, and it helps to keep them apart. The first is enzymatic: in biological matrices the native sequence is cleaved quickly by proteases, which is why published research on the native peptide often discusses its short persistence in assay systems. That is a property of the molecule in a biological environment and is unrelated to how dry powder behaves in a freezer.
The second reason is chemical. Any peptide of this length is subject to hydrolysis of its backbone amide bonds, deamidation of asparagine and glutamine residues, and oxidation of susceptible side chains such as methionine and tryptophan. Each pathway has a characteristic mass signature: deamidation adds roughly one dalton, and oxidation adds sixteen. Those small shifts are what an analytical lab looks for when a stored lot is re-tested.
How is lyophilized GLP-1 stored to limit degradation?
The catalog specifies -20 °C for lyophilized GLP-1. Lyophilization removes the water that drives hydrolysis, which is the principal reason peptides are supplied as dry powders instead of pre-dissolved material. Freezer temperature then slows the remaining pathways, since reaction rates for deamidation and oxidation fall as temperature drops.
Two controls matter in practice. The first is moisture: lyophilized peptides are hygroscopic, so a compromised closure lets the powder absorb water vapor and reopens the hydrolytic pathway. The second is thermal history. A bounded excursion, such as a short warm period in transit, shifts the material outside the condition under which its stability was characterized. Because degradation accumulates with time and temperature, the duration and magnitude of any excursion are recorded against the lot rather than dismissed.
How do researchers check that a stored lot is still what the label says?
Verification pairs two techniques that answer different questions. High-performance liquid chromatography reports purity: what share of the sample is the main species versus related impurities. Mass spectrometry reports identity: whether the dominant species still matches the theoretical 3337.73 g/mol. A lot can pass one and fail the other, which is why certificates report them as separate lines.
The comparison logic for a stored lot has three parts:
Retrieve the original certificate of analysis and note the HPLC method and the reported purity.
Re-run the same method on the stored material so the chromatograms are directly comparable.
Run mass spectrometry and look for the main peak at the expected mass, plus any satellite peaks near +1 or +16 Da that would indicate deamidation or oxidation.
Changing the method between the two runs makes the comparison meaningless, so the method line is checked before the numbers are.
How does GLP-1 compare with other GLP-class catalog entries?
Names alone are not a reliable guide. Catalog entries with GLP-style names are distinct substances with their own identifiers. The table below lists the two entries whose figures are recorded in the Upper Meadows catalog, so the differences are visible side by side.
The mass difference between the two entries is 775.85 g/mol, large enough that mass spectrometry separates them unambiguously. That is the practical reason identity is confirmed per lot by mass and never inferred from a product name. The same principle is described for a different compound in the BPC-157 research FAQ, where identity and purity are likewise reported as separate parameters.
How does sequence length influence degradation risk?
Longer peptides expose more reactive positions. With 31 residues, GLP-1 (7-37) offers a larger number of amide bonds, side chains, and neighboring-residue combinations than a short tripeptide, so there are more places for hydrolysis, deamidation, or oxidation to occur. Residue count is therefore a rough guide to how many degradation products an analyst may need to separate.
The molecular weight tells a related story. A mass of 3337.73 g/mol means that a one-dalton deamidation shift is a change of about 0.03 percent, which is small but resolvable by high-resolution mass spectrometry. A sixteen-dalton oxidation shift is clearer. Knowing the expected shifts in advance lets an analyst read a spectrum for specific mass signatures rather than scanning for any difference at all.
How should stored GLP-1 records be kept?
Stability statements are only as reliable as the records behind them. For each lot, a laboratory keeps the lot number, receipt date, certificate reference, storage temperature of -20 °C, and any logged excursion. With those fields in one place, a re-test result can be matched to the exact lot and history it describes.
The records are also what allow a negative result to be interpreted. If a re-test shows a changed profile, the lot history either supplies a plausible explanation, such as a documented warm period, or it does not, which points the investigation toward the method itself. In both cases the record narrows the question, and that is its entire purpose.
What are the limits of what a stability record can say?
A stability record documents a specific lot under specific conditions. It does not generalize to other lots, other containers, or other temperatures. A statement such as "stable at -20 °C" is bounded by the time window and the analytical methods behind it, and a reader should look for both before relying on the claim.
It is also worth separating what is measured from what is inferred. HPLC and mass spectrometry measure the sample as tested on the day of testing. Statements about how it would behave under conditions that were never tested are extrapolations, and a careful record labels them as such. For incretin-class peptides in particular, results from enzymatic-stability work in biological matrices do not transfer to the dry-powder case, and the reverse is also true.
Research-use disclaimer
Everything in this article is provided for educational and informational purposes and describes laboratory research materials only. The compounds discussed are intended for in vitro and laboratory research and are not for human or veterinary use, not for consumption, and not intended to diagnose, treat, cure, or prevent any condition. For research purposes only.
Reference
Common questions
GLP-1 is glucagon-like peptide-1, an incretin peptide studied in metabolic and receptor-signaling research. The catalog entry corresponds to the GLP-1 (7-37) fragment, a 31-residue sequence with molecular formula C151H226N40O46. It is supplied as a lyophilized powder strictly for laboratory research. For research purposes only.
The native sequence contains sites recognized by proteases, and its backbone and side chains are subject to hydrolysis, deamidation, and oxidation. Stability studies therefore track both enzymatic loss in biological matrices and slower chemical change in stored powder. Lyophilization and freezer storage address the chemical pathways, not the enzymatic ones.
The catalog specifies -20 °C for lyophilized GLP-1, in a sealed container protected from moisture and light. Removing water slows hydrolysis, and low temperature slows deamidation and oxidation. Excursions above the specified temperature are logged against the lot, because degradation is cumulative with time and temperature.
A stored lot is re-tested by HPLC to compare its chromatographic profile with the original certificate, and by mass spectrometry to confirm the dominant species still matches the theoretical molecular weight of 3337.73 g/mol. New peaks or mass shifts suggest degradation products and are recorded against the lot.
No. Catalog entries with GLP-style names have distinct CAS numbers, formulas, and molecular weights. GLP-1 is listed at 3337.73 g/mol, while the GLP-1 S entry is listed at 4113.58 g/mol. Identity is confirmed per entry by mass spectrometry, never assumed from the name.
