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FDA-approved medicine

Semaglutide Wegovy · Ozempic · Rybelsus

Semaglutide is the drug in Wegovy, Ozempic and Rybelsus. It copies a gut hormone called GLP-1, which helps control appetite and blood sugar.

What matters first

Why people look it up
People take Wegovy for long-term weight management, and Ozempic or Rybelsus for type 2 diabetes.
What the evidence shows
All three products have FDA approval. Wegovy and Ozempic are weekly injections; Rybelsus is a daily tablet, and each has its own schedule.
Dose status
With semaglutide, you start at 0.25 mg once a week for the first 4 weeks. That opening step is not the working dose — it is there to let your body get used to the drug before the label steps it up toward 1.7–2.4 mg.

Evidence snapshot

FDA-approved label

The fastest way to see what kind of evidence this page is built on.

Regulation
FDA approvedWegovy · Ozempic · Rybelsus
Dose source
FDA label schedule5 labeled steps
Safety evidence
15 listed safety findingsIncludes a boxed warning
Sources
2 cited sourcesMedical review complete · 2026-08-20
Open the shareable evidence image
Semaglutide at a glance: FDA-approved label, dosing basis, regulatory status, safety coverage, and cited-source count. These details summarize the available sources; they are not treatment recommendations.

Further down: research and dosing details · how it works · how good the evidence is · questions

Medically reviewed by Jennifer Montecillo, MD · non-practicing medical reviewerReviewed 2026-08-20open the primary sources

What is known about Semaglutide

Semaglutide is the drug in Wegovy, Ozempic and Rybelsus. Wegovy is FDA-approved for long-term weight management, and Ozempic for type 2 diabetes. The weekly injection starts at 0.25 mg. The dose may rise every 4 weeks toward 1.7 mg or 2.4 mg.

Semaglutide research and regulatory details: evidence quality, approval status, doses, handling, and presentation.
TopicValue
Strongest sourceFDA label
FDA approvalApproved (Wegovy, Ozempic, Rybelsus)
Starting dose0.25 mg once weekly for 4 weeks — from the FDA-approved label
Maintenance dosing1.7–2.4 mg once weekly — from the FDA-approved label
Half-life≈ 7 days
After mixing a multi-dose vial28 days · USP <797> multi-dose vial. General pharmacy standard — check the pharmacy label for the vial you have.
Typical vials2 mg · 5 mg · 10 mg

Every row links back to a source listed below. These facts are for reference, not a personal recommendation.

How Semaglutide works

Semaglutide acts at GLP-1 alone. Here is what that means.

GLP-1 is a hormone your gut releases when you eat. It lasts only a few minutes — an enzyme called DPP-4 breaks it down almost straight away — so the natural signal is a short burst after a meal. A GLP-1 receptor agonist is a redesigned copy of that hormone, built to survive the enzyme and to stick to proteins in your blood. That stretches a few minutes into a signal one weekly injection can hold. Everything these drugs do follows from one receptor staying switched on far longer than your body ever intended.

◆ Receptor targets1 of 4 · GLP-1 alone
4What each receptor does — 4 rows in the data table
Receptors targeted by Semaglutide, and what each receptor does
ReceptorSemaglutideWhat it does
GLP-1targetedpancreatic isletTells the pancreas to release more insulin, but only while blood sugar is already climbing, and to hold back glucagon at the same time. Because it acts only when sugar is rising, this class does not on its own push blood sugar below normal the way insulin or a sulfonylurea can.stomach and gutSlows how fast food leaves your stomach, so a meal empties gradually and you stay full for longer. This is also where the nausea, early fullness and constipation come from. The effect people want and the effect they complain about are the same effect.hindbrain and hypothalamusActs on the parts of the brain that decide when a meal is over and how appealing food seems. Appetite drops rather than having to be fought off, and most of the weight effect comes from here — not from the stomach.
GIPnot targeted—
Glucagonnot targeted—
Amylinnot targeted—

The same four receptor groups are shown for every drug, so the differences are easy to compare. Targets come from the drug class. Any result specific to Semaglutide comes from the cited sources.

Single-target GLP-1 drugs are the yardstick for every newer molecule. They act on one receptor, and their effects are well mapped. Stomach and gut side effects often limit how high the dose can go. Dual and triple agonists add other receptors in an effort to push past that limit.

What repeated weekly dosing accumulates to

A new dose can arrive before the prior one has cleared. The amount then rises toward a steady pattern over several doses. The curve uses one cited figure: the 7 days half-life. It is arithmetic, not a measurement of anyone’s blood.

◆ How repeated doses build uplong-term peak ≈ 2.00× one dose

Estimated amount compared with one dose, taken once weekly. Based on the cited half-life, not on blood test results.

10Exact values — 10 rows in the data table
Semaglutide — exposure after each once weekly dose, as a multiple of a single dose, computed from the cited half-life
WeekJust after that doseJust before the next doseToward long-term level
11.00×0.50×50%
21.50×0.75×75%
31.75×0.88×87%
41.88×0.94×94%
51.94×0.97×97%
61.97×0.98×98%
71.98×0.99×99%
81.99×1.00×100%
92.00×1.00×100%
long-term level2.00×1.00×100%

This is a math estimate based on the cited half-life of 7 days. Each dose is added to what has not yet left the body, so the curve rises toward 2.00× one dose — within 5% of that level by week 5. This is not a measured blood level and does not predict one person’s result. Source of the half-life: Wegovy (semaglutide) — FDA-approved Prescribing Information (DailyMed) · retrieved 2026-08-20.

What the evidence for Semaglutide is

The dosing numbers come from an FDA-approved prescribing label. FDA reviewed the manufacturer’s studies before approving the product, and the label can change when new dosing or safety information appears.

FDA label
What it establishes
The schedule was tested for the approved use, FDA reviewed the results, and the approved product must meet manufacturing standards.
What it does not establish
It does not show that every dose step is right for every person. A clinician still has to consider health history, side effects and other medicines.

Use these numbers for the named product and approved use. A different brand, product form or use may have a different schedule.

Where Semaglutide is in clinical trials

531 registered studies; the program has reached phase 4, and 119 are still enrolling.

The soonest a running study expects to finish measuring people is August 2026. That is when the sponsor expects to finish collecting the main measurement. It is not a results date, and not a date anything goes on sale.

  • Phase 4Recruiting

    A Proof-of-Concept Study to Evaluate Topical-Lingual Semaglutide in Adults With Obesity

    Gila Therapeutics, Inc. · Obesity & Overweight · 40 participants planned · started June 2026

    Main measurement due May 2027 (sponsor estimate)

    NCT07728383 on ClinicalTrials.gov

  • Phase 4Recruiting

    Waiting on Atrial Fibrillation Intervention Therapy (WAIT) Study

    Emma Svennberg · Atrial Fibrillation (AF), Obesity & Overweight · 200 participants planned · started March 2026

    Main measurement due December 2028 (sponsor estimate)

    NCT07275697 on ClinicalTrials.gov

  • Phase 4Recruiting

    Individualized Pharmacological Approach to Obesity in Patients With Bipolar Disorder

    Mayo Clinic · Bipolar I Disorder, Bipolar II Disorder · 100 participants planned · started January 2026

    Main measurement due February 2028 (sponsor estimate)

    NCT07213466 on ClinicalTrials.gov

A registered study means a sponsor filed a plan and started enrolling. It is not evidence the drug works, and most drugs tested in people never reach a pharmacy. Sponsors write and update these sources themselves; the National Library of Medicine publishes them without checking them.

ClinicalTrials.gov · retrieved 2026-08-23

Every compound we track, and what stage each one has reached →

Regulatory status

FDA has approved the branded pens, and the oral tablet Rybelsus.

FDA declared the semaglutide shortage resolved in February 2025. Mass compounding has wound down since. FDA has also proposed dropping it from the 503B bulks list.

Semaglutide is not on FDA’s shortage list, checked 14 August 2026. That matters here because shortage listing is what allowed compounded copies, and it is the one part of this page that can change any day.

Full regulatory tracker →

How Semaglutide compares

Each page says which kind of comparison it is: one trial that tested both, or two separate trials read side by side — which is much weaker, however close the numbers look.

Where semaglutide stands in tirzepatide vs semaglutide

Dosing, source strength, half-life and reactions for tirzepatide vs semaglutide, cited row by row past semaglutide.

The semaglutide half of wegovy vs zepbound

Each page in wegovy vs zepbound on its own terms, rather than folded into semaglutide.

Where to go next on Semaglutide

The schedule, the side effects and the mixing math each have their own page.

How long each semaglutide step is held before the next

2 published semaglutide dose values, each linked to the original source.

Every reaction on the semaglutide page, with its frequency

9 common and 6 serious semaglutide reactions, each carrying its own source.

What each water volume does to the 2 mg semaglutide vial

Every option for the 2 mg semaglutide vial, with an example draw on a U-100 barrel.

Reconstituting semaglutide at 5 mg, step by step

The 5 mg semaglutide table itself, not a general rule applied to an unrelated vial size.

The semaglutide reconstitution math, shown rather than hidden

Doses per vial, plus a 28-day use-by period with its source.

The label behind Ozempic, separate from semaglutide in general

Novo Nordisk holds NDA 209637 for Ozempic, not for semaglutide.

What Wegovy treats, alongside the semaglutide medicine guide

Wegovy is taken once weekly, on the same day each week, at any time of day, a product rule that does not come from semaglutide.

Wegovy access in United Kingdom, from semaglutide

3 NICE list-price bands run from £73.25 to £175.80, checked 2026-08-16, with semaglutide as one example

What semaglutide adds to the alcohol evidence

Injection and tablet trials answered different questions and did not all move their primary outcome. alongside semaglutide.

Semaglutide injection sites, timing and rotation

What the semaglutide Instructions for Use specify, quoted rather than paraphrased.

Safety notes

  • Prescription medicine — dosing decisions belong to the prescribing clinician
  • Escalate every 4 weeks only as tolerated

Questions about Semaglutide

Is Semaglutide FDA-approved?

Yes — it is sold as Wegovy and Ozempic and Rybelsus. That is why the schedule on this site is quoted from a label rather than summarized from a study.

How is Semaglutide taken?

By injection under the skin, once a week. The dosing page has every step, with the source on each row.

How does Semaglutide differ from the other compounds in this class?

It acts at GLP-1 alone. The nearest alternatives act elsewhere: Tirzepatide (GIP + GLP-1), Retatrutide (GIP + GLP-1 + glucagon), Cagrilintide (amylin), Survodutide (glucagon + GLP-1), Mazdutide (glucagon + GLP-1), VK2735 (GIP + GLP-1), Zenagamtide (GLP-1 + amylin), Pemvidutide (glucagon + GLP-1). Adding or removing a receptor changes both the effect and how much of it people can tolerate, so these molecules are not swappable at the same number of milligrams. Comparing them milligram for milligram is the most common mistake in this category.

What is not known about Semaglutide?

It does not show that every dose step is right for every person. A clinician still has to consider health history, side effects and other medicines.

Is there a Semaglutide dosing schedule on this site?

Yes — the label schedule is published in full, one row per step, each row carrying its source. Open the Semaglutide dosage chart.

Questions readers ask

How long to lose 30 pounds on semaglutide?

There is no published answer in weeks, because no trial reported a time to a pound target. SURMOUNT-5 reported an average of 13.7% of body weight lost after 72 weeks, across 751 adults taking semaglutide.

How many pounds that is depends on where a person started, and how fast is not something the report breaks out. The dose ladder is also slow by design. It runs 0.25 mg for four weeks, then four more steps before the 2.4 mg the result was measured at.

What is the downside of semaglutide?

The most concrete one is a boxed warning about thyroid C-cell tumors seen in rodents. The label also rules it out for a personal or family history of medullary thyroid cancer, or of MEN 2.

The everyday downside is different. Nausea, diarrhea, constipation and vomiting all sit in the label’s very common band. The drug also takes months to reach the dose the weight results came from.

Is semaglutide the same as Ozempic?

Semaglutide is the ingredient; Ozempic is one of three products that contain it. The others are Wegovy and the tablet, sold as Rybelsus and now as Ozempic tablets.

They are not interchangeable. Ozempic is approved for blood sugar in type 2 diabetes and stops at 2 mg. Wegovy is approved for weight and goes to 2.4 mg, with a 7.2 mg dose carrying its own trial.

Does semaglutide get rid of belly fat?

No cited trial measured fat loss in one specific body area. SURMOUNT-5 did measure waist size, which fell by an average of 13.0 cm with semaglutide.

Waist circumference is not the same claim as belly fat, and the trial did not scan anyone to separate fat from muscle.

2primary sources, each with the day we read it — open the documents used on this page