GLP-1 S / GLP-1 SM: STEP & SELECT Trial Evidence, Vendor Codes & Verified Prices
Semaglutide — GLP-1 Receptor Agonist (sold by research vendors as GLP-1, GLP-1 S, GLP-1 SM)
Last reviewed: 14 October 2026
Semaglutide is the compound inside Ozempic, Wegovy and Rybelsus. It copies the gut hormone GLP-1 but lasts a week instead of minutes, which is why it became the most prescribed weight-management drug in the world. Research vendors sell a lyophilised version under codes like GLP-1 S; it is not the approved product.
It makes the pancreas release insulin when blood sugar is high, lowers glucagon, slows how fast food leaves the stomach, and acts on the brain to reduce appetite. The trials of the approved drug measured about 15% body weight loss at 68 weeks in obesity and a 20% reduction in major cardiovascular events.
It is the reference compound every other GLP-class peptide is compared against, and the one with the deepest evidence. That evidence belongs to the pharmaceutical product; the research vial has none of its own.
Strong human evidence for the approved drug; none for any research vial. If you are sourcing it for laboratory work, the only things you can verify are what the vendor says it is, what the lab certificate says is in it, and what it costs — which is what the rest of this page is for.
Semaglutide is a once-weekly GLP-1 receptor agonist developed by Novo Nordisk. It is FDA-approved as Ozempic (type 2 diabetes, 2017), Rybelsus (oral, 2019) and Wegovy (chronic weight management, 2021; cardiovascular risk reduction in adults with overweight or obesity, 2024). Those are prescription medicines made under pharmaceutical controls. Research-grade semaglutide sold as a lyophilised powder is a different product: it is not approved, not reviewed for quality, and sold for in-vitro laboratory use only.
Identity note (updated 14 October 2026): since the 2025–26 enforcement wave most research vendors do not list semaglutide by name. Purgo Labs sells it as "GLP-1" (product handle /products/semaglutide, certificate lot prefix PL-SM); other vendors use GLP-1 S, GLP-1 SM, VRC-1S, PS-S1 and similar house codes. The decoder on this page shows what each vendor calls it and whether the vendor itself states the identity.
Semaglutide is a 31-residue analogue of native GLP-1(7-37). Two substitutions and a C18 fatty diacid side chain protect it from DPP-4 cleavage and bind it to albumin, taking the half-life from about two minutes for the native hormone to roughly one week.
Semaglutide is a 31-residue analog of GLP-1(7-37) with two substitutions — α-aminoisobutyric acid at position 8 (blocking DPP-IV cleavage) and arginine at position 34 — and a C18 fatty diacid attached to Lys26 through a γ-glutamate/OEG linker, which binds albumin and extends the half-life to about one week. Molecular weight 4,113.6 Da.
For background: GLP-1 (7-36 amide) is the biologically active form of native GLP-1, consisting of 30 amino acids (residues 7–36 of the full proglucagon-derived peptide) with a C-terminal amide group. The amide group is essential for full GLP-1 receptor binding activity. The molecular weight is 3,297.7 Daltons.
Native GLP-1 has an extremely short half-life of approximately 1–2 minutes in vivo due to rapid cleavage by dipeptidyl peptidase IV (DPP-IV) at the His⁷-Ala⁸ bond, and by neutral endopeptidase (NEP). This rapid degradation is the primary limitation of native GLP-1 as a therapeutic agent and has driven the development of DPP-IV-resistant analogs.
Semaglutide activates GLP-1 receptors in the pancreas, gut and brain: insulin rises only when glucose is high, glucagon falls, gastric emptying slows, and appetite drops — for a week per dose.
Semaglutide binds the GLP-1 receptor (GLP-1R), a class B G-protein-coupled receptor on pancreatic beta cells, in the gut, heart, kidney and central nervous system. Receptor activation stimulates adenylyl cyclase through Gαs, raising intracellular cAMP and engaging PKA and EPAC signalling.
In beta cells this potentiates glucose-stimulated insulin secretion only when glucose is elevated, which is why GLP-1 receptor agonists carry low intrinsic hypoglycaemia risk. Semaglutide also suppresses glucagon release from alpha cells, slows gastric emptying, and acts on hypothalamic and brainstem GLP-1R to reduce appetite and food intake. The albumin-bound depot created by the fatty diacid chain is what makes once-weekly exposure possible; native GLP-1 is cleared within minutes.
Activates GLP-1R on beta cells, stimulating adenylyl cyclase → cAMP → PKA/EPAC cascade that potentiates glucose-stimulated insulin secretion.
Insulin secretion is potentiated only in the presence of elevated blood glucose, providing an inherent safety mechanism against hypoglycemia.
Inhibits alpha cell glucagon secretion, reducing hepatic glucose output and contributing to postprandial glucose control.
Hypothalamic GLP-1R activation reduces food intake and body weight through central satiety signaling pathways.
Each outcome rated by the highest level of evidence available. Tiers follow our 5-tier methodology.
Study counts reflect peer-reviewed publications in the evidence database below. "Theoretical" outcomes have mechanistic rationale only. Learn about our evidence tiers →
Semaglutide — half-life, bioavailability, onset, and duration data
| Parameter | Value | Source |
|---|---|---|
| Half-Life (t½) | ~168 hours (7 days) Range: 155–184 hours Enables once-weekly dosing | Prescribing Information |
| Time to Peak (Tmax) | 1–3 days After subcutaneous injection | Prescribing Information |
| Bioavailability (F) | ~89% Subcutaneous injection; oral semaglutide is ~1% | Prescribing Information |
| Protein Binding | >99% Primarily albumin-bound | Prescribing Information |
| Volume of Distribution (Vd) | ~12.5 L | Prescribing Information |
| Elimination | Proteolytic cleavage; renal/fecal excretion | Prescribing Information |
| Onset of Action | 1–2 weeks Meaningful glucose reduction; weight loss effects emerge over 4–12 weeks | — |
| Duration of Action | 7 days per dose Steady state reached after 4–5 weeks | — |
Steady-state plasma concentration achieved after 4–5 weekly doses. Half-life is the longest of approved GLP-1 agonists, enabling once-weekly dosing.
References:
• Ozempic US Prescribing Information 2023
• Wegovy US Prescribing Information 2023
Peer-reviewed literature supporting the research profile of Semaglutide
The following peer-reviewed studies form the primary evidence base for Semaglutide's research profile. All references are sourced from PubMed, NCBI, and peer-reviewed scientific journals. Published research is available through PubMed, NCBI, and peer-reviewed biomedical journals.
Wilding JPH, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). New England Journal of Medicine. 2021.PMID: 33567185
−14.9% mean body weight at 68 weeks on semaglutide 2.4 mg weekly vs −2.4% with placebo; 86.4% achieved ≥5% loss.
Lincoff AM, et al. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes (SELECT). New England Journal of Medicine. 2023.PMID: 37952131
20% relative reduction in major adverse cardiovascular events over a mean 39.8 months in 17,604 adults with overweight or obesity.
Marso SP, et al. Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes (SUSTAIN-6). New England Journal of Medicine. 2016.PMID: 27633186
26% relative reduction in the primary composite of cardiovascular death, non-fatal MI or non-fatal stroke.
Davies M, et al. Semaglutide 2.4 mg once a week in adults with overweight or obesity, and type 2 diabetes (STEP 2). The Lancet. 2021.PMID: 33667417
−9.6% body weight at 68 weeks on 2.4 mg vs −3.4% placebo in adults with type 2 diabetes.
Holst JJ. The physiology of glucagon-like peptide 1. Physiological Reviews. 2007.PMID: 17928588
Reference review of GLP-1 physiology: pancreatic, gastrointestinal, cardiovascular and central effects.
Metabolic Research
Purgo Labs list price, read 12 Sep 2026 · per-lot COA on the vendor page
10mg $49.99 → $39.99 with code HEALTH (20% off; price read 2 Oct 2026)
Fast FedEx shipping · Discreet packaging
| Peptide Class | GLP-1 receptor agonist (semaglutide, 31 AA, lipidated) |
| Molecular Weight | 4,113.6 Da |
| Receptor Target | GLP-1 receptor (GLP-1R) — class B GPCR |
| Half-life | ~1 week (semaglutide); native GLP-1 ~1–2 minutes |
| Approved Products | Ozempic, Wegovy, Rybelsus (prescription only) |
| Common Vial Sizes | 5mg and 10mg (vendor-dependent) |
| Form | Lyophilized powder |
| Purity | ≥99% (third-party tested) |
View full legal status guide →
16 documented interactions for Semaglutide
Both are GLP-1 receptor agonists. Combining significantly increases risk of severe hypoglycemia, pancreatitis, and GI adverse effects. Contraindicated.
Both target GLP-1 receptors. Combining is contraindicated due to additive receptor agonism and adverse event risk.
Both affect glucose metabolism via different pathways. Monitor blood glucose closely if combining. Theoretical additive hypoglycemic risk.
MK-677 increases GH and IGF-1, which can affect insulin sensitivity. Monitor blood glucose when combining with GLP-1 agonists.
Both affect fat metabolism. AOD-9604 via lipolysis; semaglutide via appetite suppression and metabolic effects. Theoretical additive effect — monitor for excessive fat loss.
BPC-157 may support GI health and reduce nausea during GLP-1 therapy. Different primary targets with no known negative interaction.
Interaction data is based on published research, known pharmacological mechanisms, and clinical practitioner experience. Evidence tiers: Clinical = human data; Emerging = preclinical/case reports; Theoretical = mechanism-based inference. Always consult a qualified healthcare provider before combining compounds.
Source Semaglutide at Purgo Labs
10mg $49.99 list · $39.99 with code HEALTH · lab-verifiable COA per lot
Since the 2025–26 enforcement wave almost no vendor lists semaglutide by name. These are the 17 house codes we have read on vendor pages. 9 of them come with a stated identity (a CAS number, a lab lot prefix on the vendor's certificate page, or the vendor's own FAQ); the rest are codes only, and we keep those out of the price table.
Full decoder: every GLP-1, tirzepatide and retatrutide vendor code, with the evidence behind each · green = identity stated, amber = code only
Approved drug (Ozempic / Wegovy) with large randomised trials — figures below are from those trials, not from research-grade vials
Semaglutide has one of the best-characterised safety profiles of any compound on this site because it is an approved medicine studied in tens of thousands of trial participants. The dominant adverse effects are gastrointestinal and dose-related. None of that data was generated with research-grade vials, whose identity and dose are not verified by any regulator.
Research-use information only. Research-grade Semaglutide is not an approved medicine; where trial or label figures appear below they belong to the pharmaceutical product studied, not to any research vial. This section does not give dosing or medical advice.
Every rate carries its source. Where no source exists, no rate is printed.
| Effect | Rate (sourced) | Detail | Source |
|---|---|---|---|
| Nausea | 44.2% vs 17.0% placebo | Most frequent during dose escalation; mostly mild-to-moderate. | STEP 1, Wilding et al. 2021 |
| Diarrhoea | 31.5% vs 15.9% | Typically transient. | STEP 1 |
| Vomiting | 24.8% vs 6.6% | Dose-related. | STEP 1 |
| Constipation | 23.4% vs 9.5% | — | STEP 1 |
| Discontinuation for GI events | 4.5% vs 0.8% | — | STEP 1 |
| Gallbladder events, pancreatitis | not quantified | Uncommon but recognised class risks carried on the label. | Wegovy prescribing information |
| Diabetic retinopathy complications | not quantified | Signal seen in SUSTAIN-6 in people with diabetes and pre-existing retinopathy. | Marso et al. 2016 |
Regulatory status: FDA-approved as Ozempic (T2D, 2017) and Wegovy (chronic weight management, 2021). Research-grade semaglutide is not approved for any use.
Everything above describes Semaglutide the molecule. The risk specific to a research vial is different: it may not contain Semaglutide at the labelled amount, and it may contain what the synthesis left behind. Identity (mass spectrometry), purity (HPLC), measured net content and an endotoxin result are the four lines on a certificate that bear on adverse effects, and only a certificate you can check at the laboratory tells you any of them. This is what we have verified for Semaglutide so far.
12 of the 80 vendors on our scoreboard list Semaglutide with a price we read on the product page (5 Sept 2026–10 Oct 2026). Of those, 11 name their testing laboratory, 10 publish certificates that resolve on the lab's own site, and 11 publish measured milligrams against the label. The full ranking, with every dated price, is on Best Semaglutide Vendors.
| Vendor | Rubric | Lab named | Price read |
|---|---|---|---|
| MyPurePeptidepartner | 10/10 | Janoshik Analytical | $200.00 · 50mg · 10 Oct 2026 |
| Peptide Giantspartner | 10/10 | Janoshik Analytical · Vanguard Laboratory | $32.00 · 5mg · 2 Oct 2026 |
| Purgo Labspartner | 10/10 | SteriGenix · Freedom Diagnostics | $49.99 · 10mg · 2 Oct 2026 |
| Amino Clubpartner | 9/10 | ILS Labs | $49.99 · 10mg · 2 Oct 2026 |
| PeakForce Labs | 8/10 | Freedom Diagnostics (on certificates) | $69.00 · 10mg · 2 Oct 2026 |
Top 5 by rubric score; 7 more on the ranking page.
1 certificate for Semaglutide in the COA library: 0 checkable on the laboratory's own site, 0 stating measured mass against the label, 1 carrying a flag.
The pharmacology is the same if the vial contains what it claims. The difference is that nobody has verified that: a research vial may be under- or over-dosed or misidentified, which changes the risk in ways no trial has measured. Our vendor pages show which sellers publish lab-verified net content.
In STEP 1 they clustered around dose-escalation steps and mostly resolved; a minority discontinued for GI reasons (4.5%).
Side-effect section last reviewed 2026-09-12. Moved from the standalone side-effects page on 10 October 2026; text unchanged.
Semaglutide is FDA-approved as Ozempic (type 2 diabetes), Wegovy (weight management), and Rybelsus (oral, type 2 diabetes). Research-grade semaglutide is available as a research chemical. It is not a controlled substance but requires a prescription for clinical human use.
| Jurisdiction | Status as stated |
|---|---|
| United States | FDA-approved as Ozempic, Wegovy, and Rybelsus. Not a controlled substance. Research-grade semaglutide is available as a research chemical for laboratory research. The FDA has issued guidance on compounded semaglutide. |
| Canada | Approved by Health Canada as Ozempic and Wegovy. Available by prescription. |
| United Kingdom | Licensed by the MHRA as Ozempic and Wegovy. Available by prescription. |
| Australia | Approved by the TGA as Ozempic and Wegovy. Available by prescription. |
| European Union | Approved by the EMA as Ozempic and Wegovy. Available by prescription across EU member states. |
Statements above are as our legal-status page for Semaglutide stated them in 2025; they were moved here on 10 October 2026 and were not re-verified in the move. Regulations change. This is general information, not legal advice; check the current position with your own jurisdiction's regulator before relying on it.
No. Semaglutide is not listed as a controlled substance under the DEA Controlled Substances Act. It is a prescription drug but not scheduled.
Yes. Research-grade semaglutide is available as a research chemical for legitimate laboratory research purposes. It is not the same as prescription Ozempic or Wegovy.
The FDA has issued guidance on this. During drug shortages, compounding pharmacies were permitted to compound semaglutide. As the shortage resolves, the FDA has moved to restrict compounding of semaglutide.
Semaglutide is the active ingredient in Ozempic, Wegovy, and Rybelsus. Research-grade semaglutide has the same molecular structure but is produced for laboratory research purposes only.
Yes. Semaglutide is licensed as Ozempic and Wegovy in the UK and is available by prescription. Research-grade semaglutide is available for research purposes.
GLP-1 receptor agonists are among the most rigorously studied compounds in modern endocrinology. Large randomized controlled trials in humans establish both weight-loss efficacy and cardiovascular benefit for GLP-1R agonists. Claims about GLP-1 receptor biology can be stated with high confidence when tied to these trials.
Purgo Labs offers Semaglutide with ≥99% purity, third-party certificates of analysis, and fast FedEx shipping. This is an affiliate link — we may earn a commission at no cost to you.
