Semaglutide is one molecule with four different sets of numbers attached to it, and most confusion about the drug comes from mixing them up.
What it is
A 31-amino-acid analogue of glucagon-like peptide-1, the hormone the gut releases after a meal. Natural GLP-1 lasts a couple of minutes in the blood; the enzyme DPP-4 cuts it apart almost immediately. Semaglutide changes three things about the molecule, the most important being a fatty-acid chain that binds it to albumin, the most abundant protein in blood. Bound to albumin, it circulates for days instead of minutes — which is the whole reason a once-weekly injection of a peptide is possible at all.
What the receptor does when it is occupied is not one effect but several: insulin release when glucose is high, suppression of glucagon, slower stomach emptying, and reduced appetite through receptors in the brain. Weight loss and glucose control are the same mechanism read at two different endpoints.
Four approvals, four dose scales
| Product | Approved | Route | The label's dose scale |
|---|---|---|---|
| OZEMPIC injection | 2017-12-05 | Weekly injection | 0.25 mg → 0.5 mg → 1 mg → 2 mg |
| RYBELSUS tablets | 2019-09-20 | Daily tablet | 3 mg → 7 mg → 14 mg |
| WEGOVY injection | 2021-06-04 | Weekly injection | 0.25 mg → titrated → 2.4 mg (or 1.7 mg) |
| OZEMPIC tablets | on the oral application | Daily tablet | 1.5 mg → 4 mg → 9 mg |
Every figure above is read from the current FDA labelling on 2026-09-08 and is a record of what the label states, not a recommendation. Note what the table shows: the two tablet products, sold under the same manufacturer and covered by one label, run on different scales — and the label says so in its first administration instruction, that they "are not substitutable on a mg-to-mg basis."
So "semaglutide 4 mg" is a coherent statement about an OZEMPIC tablet, an impossible one about a weekly OZEMPIC injection, and something else again about RYBELSUS. A milligram figure for this drug carries no meaning until the product is named.
The step that is not meant to work
The oral label annotates its first step with an unusual admission: the 3 mg RYBELSUS starting dosage and the 1.5 mg OZEMPIC tablet starting dosage are each marked "this dosage is not effective for glycemic control."
That is not a defect. GLP-1 side effects are gastrointestinal and dose-related, and the first month exists to let the gut adapt to a drug that slows it down. The injectable scale does the same thing with its 0.25 mg step. It is worth knowing because it explains why the schedules are long, and why a figure taken from the middle of an escalation describes a stage rather than a dose.
The oral products are a delivery problem, solved narrowly
A 31-amino-acid peptide swallowed on its own is food. The tablets work because they carry an absorption enhancer that opens a narrow window in an empty stomach, and the label's conditions are unusually specific as a result: morning, empty stomach, no more than four ounces of water and no other liquid, tablets swallowed whole and never split or crushed, at least 30 minutes before eating, drinking or taking anything else by mouth.
Those conditions are part of the dose. The exposure measured in the trials assumed them.
What each product is approved for
The indications are not interchangeable either. The oral label covers glycaemic control in adults with type 2 diabetes, and reduction of major adverse cardiovascular events — cardiovascular death, non-fatal heart attack, non-fatal stroke — in adults with type 2 diabetes at high risk of them. WEGOVY is the weight-management product. Reading a weight-loss claim onto a diabetes label, or a cardiovascular claim onto a product that does not carry one, is the same category of error as reading one dose scale onto another.
What this entry does not cover
What semaglutide costs, how the products compare with tirzepatide on weight outcomes, and what happens after stopping are questions about treatment rather than about the compound. This library entry states what the molecule is, what is approved, and what the labels say.
For the research-chemical market, one thing is worth stating plainly: a vial sold under this name is not any of the four approved products, and none of the checks behind those labels apply to it.
Semaglutide is also the partner half of two investigational combinations and the benchmark the newer dual agonists are measured against: survodutide and the dual agonist developed in China both add glucagon-receptor activity to the same GLP-1 mechanism, and neither has a label of any kind.
The sharpest comparison, though, is with something that reaches the same receptor without being a peptide at all. An 883-dalton tablet now in phase 3 has a registered head-to-head trial against semaglutide, and weighs about a fifth as much. A related distinction is worth knowing when reading laboratory results in this area: the connecting peptide released alongside insulin is what distinguishes insulin a body made from insulin it received, and it is a measurement rather than anything anyone takes.
Semaglutide is the companion drug in two of the largest trials of muscle-sparing antibodies: trevogrumab's 1,005-person COURAGE study and the BELIEVE trial of bimagrumab.
Sources
- FDA labelling for OZEMPIC (NDA 209637), WEGOVY (NDA 215256) and RYBELSUS / OZEMPIC tablets (NDA 213051), retrieved through openFDA on 2026-09-08; dosage and administration sections quoted directly, oral label version dated 2026-01-30.
- Drugs@FDA original approval records: NDA 209637 approved 2017-12-05; NDA 213051 approved 2019-09-20; NDA 215256 approved 2021-06-04.