Semaglutide Testing & Verification
Mail in your semaglutide sample and get it independently verified by RP-HPLC-UV — identity, chromatographic purity, and net-peptide content, measured against a certified reference standard.
What Semaglutide is
Semaglutide is a synthetic glucagon-like peptide-1 (GLP-1) receptor agonist: a 31-amino-acid peptide backbone based on human GLP-1(7-37) with substitutions (including Aib at position 8) and, most importantly for analysis, a C18 fatty-diacid (lipid) side chain attached to a lysine through a short linker. That acylation, plus the unnatural Aib residue, gives it a molecular weight near 4,114 g/mol and makes it a structurally complex peptide to manufacture consistently. On the research-chemical and grey market it is sold as a lyophilized powder with no regulated identity or content guarantee — distinct from any approved finished drug product — which is exactly why independent verification of a given vial is worthwhile.
Why get your Semaglutide independently tested
- Wrong-compound or analog substitution: semaglutide, tirzepatide, retatrutide, and liraglutide are all lipidated GLP-class peptides that look identical as a white powder. Retention-time and UV-spectral matching against a certified semaglutide reference standard confirms the vial holds semaglutide and not a different analog.
- Acylation integrity: the C18 fatty-diacid side chain is a defining feature. A des-acyl or truncated backbone is a chemically different molecule that elutes differently on reversed-phase HPLC, so identity testing flags material missing its lipid modification.
- Net-peptide content vs. label: lyophilized vials carry counter-ion salt, residual moisture, and bulking agents on top of peptide. A net-peptide assay reports the actual milligrams of semaglutide per vial, exposing underfilling or an inflated label claim.
- Blend and purity checks: semaglutide is often co-formulated with cagrilintide ('CagriSema'), and its long acylated sequence is prone to deletion, truncation, and incomplete-conjugation by-products. Chromatographic purity as area percent quantifies the main peak versus related substances, and blends can be resolved into separate peaks.
What we measure on Semaglutide
Every semaglutide sample is analyzed by reversed-phase HPLC with UV/diode-array detection at 214 nm against a certified reference standard. We report three results per certificate: identity (retention-time and UV-spectral match to the reference), chromatographic purity as area percent of the main peak, and net-peptide assay as milligrams of peptide per vial. For a CagriSema-type blend, the components are resolved and reported separately where the method and available reference standards allow.
Every result is issued as a certificate of analysis you — or anyone you forward it to — can verify cryptographically. Reporting identity, purity, and milligram content is the point: a vial can be pure and still underfilled, so we report all three. More on purity vs. net-peptide content and how to read a peptide COA.
Our scope — stated plainly
Testing is RP-HPLC-UV against a certified reference standard, not mass spectrometry — identity is a retention-time and UV-spectral match rather than a direct mass measurement. Semaglutide reference standards are commercially available, so identity testing does not usually require a sourcing delay. KMD Analytical is an independent laboratory; we do not perform sterility, endotoxin, heavy-metal, or residual-solvent testing.
KMD is an independent RP-HPLC-UV lab. We do not run LC-MS / mass-spec, sterility, endotoxin, or heavy-metal testing. If your job needs a capability we don't have, we'll say so.
Semaglutide testing — FAQ
Can you tell semaglutide apart from tirzepatide or retatrutide?
Yes. Each is a distinct lipidated peptide with its own retention time and UV spectrum under our RP-HPLC-UV method. By comparing your sample against a certified semaglutide reference standard, we confirm whether the material matches semaglutide or is a different GLP-class analog. Identity here is a retention-time and UV-spectral match, not a mass-spectrometry sequence confirmation.
Can you verify a CagriSema (cagrilintide + semaglutide) blend?
Yes, where the two peptides resolve chromatographically. We report each component's peak and can provide a net-peptide figure for each where suitable reference standards are available. Tell us the expected components and ratio so we compare against the right standards.
Does the milligram number on my vial mean milligrams of peptide?
Not necessarily. Lyophilized vials are labeled by fill weight, which can include counter-ion salt, residual moisture, and bulking agents. Our net-peptide assay reports the actual milligrams of semaglutide per vial, so you can compare real peptide content to the label.
Other peptides we test
Retatrutide · Cagrilintide · Tesamorelin · BPC-157 · see the full panel.