Sourcing Guide

Semaglutide in the US: Research-Grade, Verified by Batch

The most-studied GLP-1 analog, the difference between a research vial and a prescription product, and what a certificate has to prove

May 7, 2026·Compiled by Eppix Labs

Semaglutide is the most heavily studied molecule in this entire category, which creates a specific problem for anyone buying it as a research material: the evidence base is so large and so public that it is easy to forget it was generated with pharmaceutical-grade material through a regulated channel, and not with a research vial.

This guide covers the molecule, the trial record, the boundary between research and pharmacy supply, and the certificate checks that matter. Research-grade semaglutide is a laboratory material with no human-use authorization in the US.

Chemical Identity

Name: Semaglutide
Also known as: Semaglutide, NN9535
Molecular formula: C₁₈₇H₂₉₁N₄₅O₅₉
Molecular weight: 4113.6 g/mol
CAS number: 910463-68-2
Salt forms: Acetate (research supply) · Sodium (approved formulations)

What semaglutide is

Semaglutide is a 31-residue acylated analog of human GLP-1, described in its discovery paper by Lau et al. (2015).[4] Three modifications carry the design: an Aib substitution at position 8 that blocks DPP-4 cleavage, an Arg substitution at position 34, and a C18 fatty diacid attached through a spacer at Lys26 that drives albumin binding. Together they take the half-life from minutes to roughly a week.

It is a single-receptor agonist. Every published effect runs through the GLP-1 receptor, which is what distinguishes it from tirzepatide and retatrutide and what makes it the cleanest available tool compound for isolating GLP-1 receptor pharmacology.

General Image — Semaglutide lyophilized research material as supplied by Eppix Labs. Labelled and measured content are stated on the certificate below.

Sequence and structure

Around 4114 Da, 31 residues, acylated, with two non-natural substitutions in the backbone. The acylation is where research-grade material most often goes wrong: an under-acylated or non-acylated variant has a different mass and a different half-life and looks broadly similar on a purity trace. That is a specific, well-known failure mode, and it is why the mass on an identity report matters more than the percentage on a purity report.

Amino Acid Sequence diagram — Amino-acid sequence of semaglutide, read N-terminus to C-terminus.

Chemical Structure diagram — Chemical structure of semaglutide.

What the published trials reported

Stated as trial findings from named, published, randomized studies. None of these is a claim about a research vial:

·Obesity. Wilding et al., New England Journal of Medicine 2021 (STEP 1): 68 weeks, randomized, double-blind, placebo-controlled, reporting mean body-weight change of about -14.9% against -2.4% for placebo.[1]
·Cardiovascular outcomes in type 2 diabetes. Marso et al., New England Journal of Medicine 2016 (SUSTAIN-6): a pre-approval cardiovascular safety trial reporting a lower rate of the composite primary outcome against placebo.[2]
·Cardiovascular outcomes without diabetes. Lincoff et al., New England Journal of Medicine 2023 (SELECT): in adults with overweight or obesity and established cardiovascular disease but not diabetes, a lower rate of major adverse cardiovascular events against placebo.[3]
·Discovery. Lau et al., Journal of Medicinal Chemistry 2015: the design and structure-activity work behind the once-weekly analog.[4]

The limit of the evidence

Every trial above used GMP material at defined doses under clinical supervision. the FDA has authorized specific semaglutide products for specific human indications through the pharmacy channel. Research-grade semaglutide is outside that authorization, is not a medicine, and carries no human-use permission.

The size of the published evidence base is a reason to find the molecule scientifically interesting. It is not evidence about any particular vial, which is what a batch certificate is for.

Verifying a semaglutide lot

The three lines: MS identity against the expected mass near 4114 Da, which catches non-acylated variants and cheaper substitutes; HPLC purity, which quantifies synthesis by-products; and measured content against the labeled amount, which catches underfilling. A supplier that publishes only a purity percentage has answered one of the three questions.

Every Eppix semaglutide lot is tested by Janoshik Analytical, published before sale and verifiable on the laboratory's own database.

Certificate of analysis for Semaglutide 10mg, batch SEMA-CA-26C-01, 99.504% purity, 11.27 mg measured content — Published certificate for the current semaglutide lot, read live from the batch record.

Sourcing in the United States

Domestic fulfillment is by FedEx, typically one to three business days across the United States, free over $200 USD, with card and PayPal checkout and mix-and-match pricing at 5 and 10 vials.

The direct mechanistic comparison is at semaglutide vs tirzepatide, and the tirzepatide sourcing guide is at buy tirzepatide in the US.

Available at Eppix Labs

Semaglutide

10mg

Every batch tested by an independent laboratory, with the certificate published before sale.

From $59.99 USDIn stock

Frequently Asked

The molecule is the same; the supply chain, specification, release testing and legal status are not. Approved products are GMP-manufactured and dispensed on prescription. A research vial is manufactured to a supplier specification and labeled for laboratory use only.

Research-grade semaglutide may be sold and held for laboratory use, and is not authorized for human or veterinary use in that form. the FDA authorizations for semaglutide medicines apply to approved products through the pharmacy channel. This is not legal advice.

Semaglutide agonizes the GLP-1 receptor alone. Tirzepatide agonizes both GIP and GLP-1 receptors from one molecule. SURPASS-2 compared them head to head in type 2 diabetes.

Incomplete or absent acylation. The fatty-diacid side chain is what gives the molecule its half-life, and material missing it has a different mass while looking broadly similar on a purity trace. An MS identity line is what catches it.

Batch number matching the vial, the named testing laboratory with an independent verification path, MS identity against the expected mass, HPLC purity, and measured content against the labeled amount.

Lyophilized: cool, dry, dark, at -20 °C for long-term storage. Reconstituted: refrigerated, used within the window your protocol defines.

References

Wilding, J.P.H. et al. (2021). Once-weekly semaglutide in adults with overweight or obesity. N Engl J Med 384(11):989-1002. PMID 33567185
Marso, S.P. et al. (2016). Semaglutide and cardiovascular outcomes in patients with type 2 diabetes. N Engl J Med 375(19):1834-1844. PMID 27633186
Lincoff, A.M. et al. (2023). Semaglutide and cardiovascular outcomes in obesity without diabetes. N Engl J Med 389(24):2221-2232. PMID 37952131
Lau, J. et al. (2015). Discovery of the once-weekly glucagon-like peptide-1 (GLP-1) analogue semaglutide. J Med Chem 58(18):7370-7380. PMID 26308095

Tirzepatide

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Semaglutide

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Research Use Only

This article summarizes published preclinical research literature. Compounds referenced are supplied by Eppix Labs strictly as research materials for laboratory investigation within the United States. They are not approved by the FDA for human or veterinary use, and nothing on this page should be interpreted as medical advice or guidance on human or animal administration.