Compound guide · Tier A
Semaglutide
The most studied GLP-1 on the market, with a cardiovascular outcomes trial behind it. Also the compound most widely counterfeited and most widely sold as research material.
The short answer
A genuine advance with an unusually strong evidence base for obesity medicine. Nothing about that record transfers to a vial bought from a research chemical vendor.
At a glance
| Class | GLP-1 receptor agonist |
| Developer | Novo Nordisk |
| Sold as | Ozempic, Wegovy, Rybelsus |
| Regulatory status | Approved. Type 2 diabetes, chronic weight management, and cardiovascular risk reduction in people with obesity or overweight and established cardiovascular disease. Available in injectable and oral forms. |
| Compounding status | Semaglutide came off the FDA shortage list, which ended the shortage-based compounding route. Compounded semaglutide is not an FDA-approved product. |
| Anti-doping | Not specifically listed, but captured by S0 for any use outside an approved therapeutic context in tested sport. |
| Our evidence tier | Tier A. Approved medicine |
What it is
Semaglutide is a synthetic analogue of GLP-1, a hormone released from the gut after eating. It binds the GLP-1 receptor, slowing gastric emptying, increasing satiety and improving glucose-dependent insulin release. Structural modifications give it a half-life long enough for once-weekly dosing, which is what separated it from the daily GLP-1 drugs that came before.
Who it is for, and who actually takes it
The approved populations are adults with type 2 diabetes, and adults with obesity or with overweight plus a weight-related comorbidity. The cardiovascular indication covers people with established cardiovascular disease and obesity or overweight but without diabetes.
The people buying it as research material are overwhelmingly outside those populations, or inside them but unable to access or afford the approved product. That gap is what the grey market sells into.
What the research shows
Mean weight change at 68 weeks, STEP 1
Adults with obesity or overweight without diabetes, randomised to semaglutide 2.4 mg weekly or placebo.
View as table
| Group | % mean weight loss |
|---|---|
| Placebo | 2.4% |
| Semaglutide 2.4 mg | 14.9% |
Source: STEP 1, published 2021.
Dosing
| Stage | Dose |
|---|---|
| Weeks 1 to 4 | 0.25 mg once weekly |
| Weeks 5 to 8 | 0.5 mg once weekly |
| Weeks 9 to 12 | 1.0 mg once weekly |
| Weeks 13 to 16 | 1.7 mg once weekly |
| Week 17 onward | 2.4 mg once weekly, the maintenance dose |
This is the escalation schedule set out in the Wegovy prescribing information for chronic weight management, reproduced as published. Escalation exists to limit gastrointestinal adverse effects. The label allows a temporary reduction to 1.7 mg for up to four weeks if 2.4 mg is not tolerated, and discontinuation if it still is not. Doses for type 2 diabetes differ. This is a record of what the label says, not a recommendation, and it applies to the approved product administered under prescription.
What happens when you come off it
Weight regain after discontinuation is the rule rather than the exception. In the STEP 1 extension, participants who came off semaglutide regained roughly two thirds of the weight they had lost within a year. In STEP 4, a 20-week run-in produced 10.6% mean loss; those switched to placebo regained about 6.9% of baseline body weight over the following year while those who continued lost a further 7.9%. The trial evidence describes a maintenance therapy, not a course.
What it is being studied for
| Area | Stage of evidence |
|---|---|
| Type 2 diabetes | Approved |
| Chronic weight management | Approved |
| Cardiovascular risk reduction | Approved |
| Metabolic dysfunction-associated steatohepatitis | Regulatory activity reported during 2026 |
| Heart failure with preserved ejection fraction, chronic kidney disease, and further metabolic indications | Trials registered and reporting |
Common myths
Research grade semaglutide is the same thing as Wegovy.
It may be the same molecule. It is not the same product. The approved version is sterile, endotoxin tested, dose controlled and delivered in a metered pen under a regulatory quality system. Research material is typically tested for purity and identity only, then reconstituted and measured by the buyer.
Compounded semaglutide is an FDA approved alternative.
Compounded drugs are not FDA approved. The shortage-based compounding route closed when semaglutide came off the shortage list, and regulators have documented counterfeit product, false labelling naming pharmacies that had not made the material, and tenfold dosing errors from multidose vials.
It is just an appetite suppressant.
Appetite reduction is one effect. The cardiovascular outcomes data showing reduced major adverse cardiovascular events is not explained by appetite alone, and is the reason regulators and payers reclassified this drug class.
You take it until you reach your goal weight, then stop.
The discontinuation data says otherwise. Roughly two thirds of lost weight returns within a year of stopping.
Verifying a purchase
Semaglutide is the most counterfeited compound in this category, so identity confirmation matters more here than almost anywhere. Insist on mass spectrometry against the stated molecular formula, not purity alone, and check that the lot number on the certificate matches the vial. Net peptide content is particularly important because the approved product is dosed in fractions of a milligram, so an unstated content figure makes any calculation from vial mass unreliable.
The general method is set out in our guide to reading a certificate of analysis, which covers the eleven checks that apply to any compound. The points above are the ones specific to Semaglutide.
Caveats and safety
Gastrointestinal adverse effects are common and dose dependent. Labels carry a boxed warning regarding thyroid C-cell tumours observed in rodents, with contraindications in personal or family history of medullary thyroid carcinoma or MEN 2. Gallbladder disease and pancreatitis appear in the safety record. Lean tissue loss accompanies total weight loss and is an active research question.
Where to get it
We have no vendor link for Semaglutide. Our affiliate partner does not stock it, and we do not link to sellers we have not looked at.
Sources
- Wegovy prescribing information, FDA
- Drugs@FDA approval record
- Weight regain after GLP-1 interruption, narrative review of randomised studies
- FDA concerns with unapproved GLP-1 drugs used for weight loss
Related compounds
Disclosure. PeptoPurity is an affiliate of CertaPeptides and earns a commission on qualifying purchases made through the vendor link on this page, at no additional cost to you. That relationship does not set the evidence tier, alter the verdict, or change a word of the assessment. Our Tier C and Tier D pages carry the same links as our Tier A pages, with the same conclusions we would publish if we earned nothing. Where the registered, prescribed route is the better option, we say so on the page that would otherwise pay us.
Scope. This is an evidence review, not medical advice. Where an approved label schedule is reproduced it is a record of what a regulator has published about a licensed medicine, not a recommendation and not a schedule for anyone to follow unsupervised. For unapproved compounds we report only the doses used in published studies, attributed to those studies, and we publish no protocols and no reconstitution guidance for any compound. Regulatory status differs between countries and changes over time. Material sold for laboratory research is not approved for human use. Decisions about treatment belong with a qualified prescriber.