Semaglutide is a GLP-1 (glucagon-like peptide-1) receptor agonist, a prescription medication that mimics a natural gut hormone to help regulate blood sugar and appetite. It is FDA-approved and sold under brand names Ozempic, Rybelsus, and Wegovy. It must be prescribed and supervised by a licensed clinician.

Is semaglutide the same as Ozempic and Wegovy?

Yes — semaglutide is the active ingredient in all three. Ozempic and Rybelsus are approved for type 2 diabetes, and Wegovy is approved for weight management. They differ in dosing and approved indication, which is why a clinician matches the right product to the right patient.

Is semaglutide FDA-approved?

Yes. Unlike many research peptides, semaglutide is FDA-approved and is a prescription medication. It should only be obtained through a licensed pharmacy with a valid prescription and used under medical supervision.

What are the common side effects of semaglutide?

Commonly reported side effects include nausea, vomiting, diarrhea, constipation, and abdominal discomfort, especially when starting or increasing the dose. Serious risks are described in the prescribing information, including a boxed warning about thyroid C-cell tumors seen in rodents. A prescribing clinician reviews these risks for each patient.

Why does WikiPeps cover a prescription drug?

Because semaglutide is one of the most discussed peptide-based medications, and accurate, non-promotional education helps people ask their clinician the right questions. WikiPeps does not sell semaglutide and does not provide dosing or sourcing guidance for prescription drugs.

Peptide library

Semaglutide

Name: Semaglutide
Creator: The WikiPeps Editorial Team
Published: 2026-05-31

Semaglutide is a prescription GLP-1 receptor agonist medication approved by the FDA and sold as Ozempic and Rybelsus for type 2 diabetes and Wegovy for chronic weight management. It is a prescription drug, not a research chemical, and must be used under medical supervision.

The WikiPeps Editorial Team4 min readReviewed May 31, 2026

Also known asGLP-1OzempicWegovyRybelsusGLP-1 receptor agonist

In plain words

Semaglutide is the medicine inside Ozempic and Wegovy. It copies a natural gut hormone that tells your brain you’re full, so people use it to eat less, lose weight, and steady blood sugar.

Key facts

Category: Prescription weight-loss med
Legal / FDA status: FDA-approved prescription medication (Ozempic, Wegovy, Rybelsus)
Half-life: Approximately 1 week (about 165 hours), supporting once-weekly injectable dosing
Typical form: Manufacturer prefilled injection pen (Ozempic, Wegovy) or oral tablet (Rybelsus)
Also known as: Ozempic, Wegovy, Rybelsus, GLP-1 receptor agonist

How it's delivered

Subcutaneous injection (approved product is a metered pen)

The approved semaglutide products (Ozempic/Wegovy) are once-weekly subcutaneous injections delivered by a finished, pre-filled metered pen — there is no patient reconstitution step. An oral tablet form (Rybelsus) also exists. Reconstituting a research vial is not how the approved medicine is supplied; semaglutide is prescription-only.

Also seen: oral (Rybelsus tablets)

Source: FDA prescribing information — Ozempic/Wegovy (subcutaneous once weekly) and Rybelsus (oral).

How to mix & dose

Semaglutide dosage calculator

Semaglutide is the prescription drug Ozempic/Wegovy/Rybelsus, dosed once weekly per its FDA label (titrated to 2.0–2.4 mg). The approved product is a metered pen with no reconstitution; the math here is for research vials only.

10 mg 20 mg Dosing guide

Calculate for your vial

Plug in the mg on your Semaglutide vial, the water you added, and your dose — get the exact units to draw.

Reconstitution Calculator

Units to draw (U-100)10units

Volume to draw0.1mL

Concentration5mg/mL

Per insulin unit50mcg

Doses per vial20doses

Check the decimal. A misplaced decimal point here is a 10× dosing error. Re-read every number, and confirm your dose with a licensed clinician before you draw.

Educational only — not a dosing recommendation. This tool does the measurement math; it does not tell you what to take. On a U-100 insulin syringe, 100 units = 1 mL.

Dosing schedule

Semaglutide · fixed weekly step-up schedule

Optional

A fixed weekly titration ladder. Body weight and goal are context, not a formula — people with more to lose more often climb toward the 2.4 mg maintenance dose.

10.25 mg/wkWeeks 1–4Starting dose
20.5 mg/wkWeeks 5–8
31.0 mg/wkWeeks 9–12
41.7 mg/wkWeeks 13–16
52.4 mg/wkWeek 17+Maintenance / max

Everyone starts at 0.25 mg and steps up every 4 weeks on the same schedule — the ladder is not calculated from body weight. Someone with more to lose more often titrates toward the 2.4 mg maintenance dose, while a lighter person losing well with few side effects may hold at a lower step. The dose is individualized by tolerability and response under medical supervision, not from your weight.

Source: FDA label — Wegovy® (semaglutide). Educational only — not medical advice and not a dosing recommendation. Any dosing decision belongs with a licensed clinician.

Semaglutide is a prescription GLP-1 receptor agonist medication approved by the FDA and sold as Ozempic and Rybelsus for type 2 diabetes and Wegovy for chronic weight management. It is a prescription drug, not a research chemical, and must be obtained and used under the supervision of a licensed clinician. This page is purely educational and is not medical advice.

Important: Unlike the research peptides elsewhere in this library, semaglutide is an approved medicine. WikiPeps does not sell it, does not provide dosing or sourcing guidance, and does not instruct self-administration. The goal here is to help you understand the drug so you can have a better conversation with your prescriber.

What is semaglutide?#

Semaglutide is a GLP-1 (glucagon-like peptide-1) receptor agonist — a medication that mimics a natural hormone released in the gut after eating. By activating GLP-1 receptors, it helps regulate blood sugar and appetite. It is the active ingredient in the brand-name products Ozempic, Rybelsus, and Wegovy, and it is FDA-approved.

What is semaglutide used for?#

Its approved uses depend on the specific product, and a prescribing clinician matches the product to the patient.

Brand	Form	FDA-approved use
Ozempic	Once-weekly injection pen	Type 2 diabetes blood-sugar control; cardiovascular risk reduction in certain adults
Rybelsus	Daily oral tablet	Type 2 diabetes blood-sugar control
Wegovy	Once-weekly injection pen	Chronic weight management in eligible adults and adolescents

Eligibility, indication, and dosing are clinical decisions. Using a diabetes product for weight loss, or vice versa, is something only a prescriber should determine.

How does semaglutide work?#

Semaglutide activates GLP-1 receptors, which in turn:

Stimulate insulin release when blood sugar is high.
Reduce glucagon secretion (a hormone that raises blood sugar).
Slow gastric emptying, so food leaves the stomach more slowly.
Act on appetite centers in the brain to increase satiety.

Its long half-life of about one week is what allows the injectable forms to be dosed weekly.

How is semaglutide administered?#

This section is descriptive only — it is not instruction to self-inject. Injectable semaglutide (Ozempic, Wegovy) is supplied as a manufacturer prefilled pen designed for once-weekly subcutaneous injection, typically into the abdomen, thigh, or upper arm. Patients are trained directly by their clinician or pharmacist, and the pen, needles, and storage are handled per the manufacturer's instructions for use. Rybelsus is a daily oral tablet taken on an empty stomach with a small sip of water.

Because semaglutide pens are finished, FDA-regulated products, there is no patient reconstitution step the way there is with lyophilized research peptides. The pen is used as supplied.

What are the side effects and risks?#

Commonly reported side effects include nausea, vomiting, diarrhea, constipation, and abdominal discomfort, particularly when starting or increasing the dose. The prescribing information also describes more serious considerations, including a boxed warning about thyroid C-cell tumors observed in rodents (it is contraindicated in people with a personal or family history of medullary thyroid carcinoma or MEN 2), and potential risks such as pancreatitis, gallbladder problems, and hypoglycemia when combined with other diabetes medicines. Only a prescribing clinician can weigh these risks for an individual.

Why does counterfeit and compounded semaglutide matter?#

Because demand is high, the FDA has warned about counterfeit and improperly compounded semaglutide products, including dosing errors and unverified ingredients. The safest path is a legitimate prescription filled at a licensed pharmacy. WikiPeps strongly discourages sourcing prescription drugs outside the regulated system and does not facilitate it.

The bottom line#

Semaglutide (Ozempic, Wegovy, Rybelsus) is an FDA-approved prescription GLP-1 medication for type 2 diabetes and chronic weight management. It is a real medicine with real risks, not a research chemical, and it should only be obtained with a valid prescription and used under a licensed clinician's supervision. Use this page to understand it and to ask your prescriber informed questions.

Side effects & safety

As an FDA-approved GLP-1, its side effects are well documented — mostly gastrointestinal, and heaviest while the dose steps up.

Commonly reported

Nausea
Diarrhea or constipation
Vomiting
Reduced appetite / early fullness
Stomach discomfort or reflux

Less common — worth knowing

Gallbladder problems
Pancreatitis (rare)
Injection-site reactions

Carries a boxed warning for thyroid C-cell tumors (seen in rodents) and is not for people with a personal/family history of medullary thyroid cancer or MEN2. A prescriber screens for this.

Educational only — not medical advice. Everyone responds differently; talk to a licensed clinician before starting Semaglutide, and stop and seek medical care for any severe or unusual reaction.

Tried Semaglutide, or have a question about it?

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Frequently asked questions

What is semaglutide?: Semaglutide is a GLP-1 (glucagon-like peptide-1) receptor agonist, a prescription medication that mimics a natural gut hormone to help regulate blood sugar and appetite. It is FDA-approved and sold under brand names Ozempic, Rybelsus, and Wegovy. It must be prescribed and supervised by a licensed clinician.
What is semaglutide used for?: Ozempic and Rybelsus are FDA-approved to improve blood sugar in adults with type 2 diabetes (Ozempic also for reducing cardiovascular risk in certain patients). Wegovy is approved for chronic weight management in eligible adults and adolescents. Uses and eligibility are determined by a prescribing clinician.
Is semaglutide the same as Ozempic and Wegovy?: Yes — semaglutide is the active ingredient in all three. Ozempic and Rybelsus are approved for type 2 diabetes, and Wegovy is approved for weight management. They differ in dosing and approved indication, which is why a clinician matches the right product to the right patient.
Is semaglutide FDA-approved?: Yes. Unlike many research peptides, semaglutide is FDA-approved and is a prescription medication. It should only be obtained through a licensed pharmacy with a valid prescription and used under medical supervision.
What are the common side effects of semaglutide?: Commonly reported side effects include nausea, vomiting, diarrhea, constipation, and abdominal discomfort, especially when starting or increasing the dose. Serious risks are described in the prescribing information, including a boxed warning about thyroid C-cell tumors seen in rodents. A prescribing clinician reviews these risks for each patient.
How is semaglutide administered?: Injectable semaglutide (Ozempic, Wegovy) comes in a manufacturer prefilled pen for once-weekly subcutaneous injection, and Rybelsus is a daily oral tablet. Patients are trained by their clinician or pharmacist; this page describes the products factually and is not self-administration instruction.
Why does WikiPeps cover a prescription drug?: Because semaglutide is one of the most discussed peptide-based medications, and accurate, non-promotional education helps people ask their clinician the right questions. WikiPeps does not sell semaglutide and does not provide dosing or sourcing guidance for prescription drugs.

References

1.Ozempic (semaglutide) injection — FDA Prescribing Information — Novo Nordisk / U.S. Food and Drug Administration · 2024
2.Wegovy (semaglutide) injection — FDA Prescribing Information — Novo Nordisk / U.S. Food and Drug Administration · 2024
3.Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1 trial) — New England Journal of Medicine (PubMed-indexed) · 2021
4.FDA warns against compounded semaglutide products and counterfeit risks — U.S. Food and Drug Administration · 2024

What the research shows

FDA-approved drug

Semaglutide is the active ingredient in FDA-approved medicines (Ozempic, Wegovy, Rybelsus) backed by large randomized phase 3 trials and a cardiovascular-outcomes trial. The evidence here is among the strongest of any peptide in the library.

Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1)
Wilding JPH, Batterham RL, et al. · 2021 · N Engl J Med 2021;384:989-1002
View source NCT03548935
Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes (SUSTAIN-6)
Marso SP, Bain SC, et al. · 2016 · N Engl J Med 2016;375:1834-1844
View source NCT01720446

Citations are real, published sources, graded conservatively. Educational only — not medical advice, and not an endorsement to use any compound.

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Comments & experiences

What members are saying about Semaglutide — questions, observations, and lived experience. Not medical advice.

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