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Semaglutide

Also known as Ozempic, Wegovy, Rybelsus, GLP-1 receptor agonist

Approved for some usesMetabolic & weight loss

Last reviewed · Awaiting clinical review

Main safety concerns

Well studied and approved, but not for anyone with a personal or family history of medullary thyroid cancer or MEN2. Nausea and other gut effects are common, especially when the dose goes up.

Educational information, not medical advice. If you have symptoms that worry you, contact a clinician or emergency services.

What is known

A GLP-1 receptor agonist approved for type 2 diabetes and weight loss, sold as Ozempic, Wegovy, and Rybelsus.

Status:
FDA approved for type 2 diabetes and weight loss, sold as Ozempic, Wegovy, and Rybelsus. Research vials are not the approved product.[4]
Strongest evidence for any claim:

See the evidence claim by claim

On this page

What it is and how it works

Semaglutide copies , a gut hormone released after eating. It lowers appetite, slows how fast the stomach empties, and helps the pancreas release insulin when blood sugar is high. The result is less hunger and steadier blood sugar. It is approved by the FDA for type 2 diabetes (Ozempic) and for weight loss (Wegovy), with a daily tablet version as well (Rybelsus). A fatty acid chain lets it bind to albumin, which stretches its to about a week and allows once weekly dosing.[1] [4]

Evidence by claim

Each claim is graded on its own. Tap a grade to see what it does and does not mean.

Reported side effects

  • SeriousAcute pancreatitis(rare)[4]Seek care for severe, lasting abdominal pain.
  • WarningGallbladder problems, including gallstones(uncommon)[4]Rapid weight loss can raise the risk of gallstones.
  • CautionNausea(common)[3]The most common effect, worst in the days after a dose increase, then it eases.
  • CautionVomiting, diarrhea, or constipation(common)[3]
  • InfoReduced appetite(common)[3]Expected, and part of how the drug works.

Interactions and combination risks

  • WarningInsulin or sulfonylureas[4]

    Raises the risk of low blood sugar. These medicines may need to be lowered under medical supervision.

  • CautionOral medications[4]

    Semaglutide slows stomach emptying, which can change how quickly swallowed drugs are absorbed.

  • WarningOther GLP-1 or incretin drugs (tirzepatide, retatrutide)

    Do not combine drugs in this class. Using more than one at once stacks the gut effects and risks with no proven benefit.

Who should avoid it

  • SeriousPersonal or family history of medullary thyroid cancer, or MEN2

    Carries an FDA boxed warning based on thyroid C cell tumors seen in rodents. No clear human cases, but the warning stands.

  • SeriousPregnancy or breastfeeding

    Not for use in pregnancy. It is generally stopped well before trying to conceive.

  • WarningHistory of pancreatitis

    A possible pancreatitis signal means extra caution.

Dosing

Placed after the evidence and risks on purpose. Nothing here is a recommendation for you.

Doses studied in human trials
Route(s)subcutaneous, once weekly (Ozempic, Wegovy), oral, once daily (Rybelsus)
Typical rangeInjectable: start 0.25 mg weekly and step up every 4 weeks through 0.5, 1.0, and 1.7 mg to a target of up to 2.4 mg for weight loss. Diabetes doses usually top out around 1 to 2 mg.
FrequencyOnce weekly by injection, or once daily as the oral tablet
Half life used in the model7 days
Cycle guidanceTitrated up over about 16 weeks, then used continuously.
NotesThe slow exists to limit nausea. With a around 7 days, semaglutide builds up over the first month or so before it levels off, which is why each dose step is held for 4 weeks. See the plot below. Because it slows stomach emptying, it can change how fast other swallowed medicines are absorbed.
[4]

For the equipment itself, see syringes, needles, and the rest of the kit.

Saturation model (simplified)

A textbook one compartment model of how Semaglutide could build up with repeated doses. It is a shape, not a measured blood level. The starting values mirror the table above for illustration only.

This is not syringe units. The dose below is the actual amount of compound, in micrograms (mcg) or milligrams (mg). If you only know your dose as units on the syringe, use the reconstitution calculator to convert units to mcg or mg first.
Simplified model

Modeled amount in the body over time

Assumes evenly spaced doses, instant absorption, and one compartment first order clearance at the half life you entered. The vertical axis is modeled amount remaining in mg, not a measured blood concentration, and real levels vary between people.

00.61.11.72.2wk 024681012141618plateau average

Plateau average (modeled)

1.4 mg

Peak / trough

2 / 1

Time to about 90% of plateau

3.3 wk

Share of plateau at cycle end

100%

Semaglutide: in this model the amount reaches about 90% of its plateau after 3.3 weeks, and is at 100% of that plateau when dosing stops at week 16.

Show the modeled values as a table
Modeled amount by week, in mg
WeekSemaglutide (mg)
01
11.5
21.8
31.9
41.9
52
62
72
82
92
102
112
122
132
142
152
161
170.5
180.2

An educational estimate, not a clinical simulation or dosing advice.

Reconstitution

Vial sizes5 mg, 10 mg
DiluentBacteriostatic water for multi dose vials, or sterile water for single use
ConcentrationExample: a 5 mg vial plus 2 mL of water gives 2.5 mg/mL, so a 1 mg dose is 0.4 mL, which is 40 units on a U-100 syringe. Research vials vary, so check your label.
NotesThe approved products come as prefilled pens or single dose vials with their own instructions. Research material is sold as lyophilized vials, commonly 5 mg or 10 mg.

General reconstitution technique

Units and volume arithmetic

Converts between an amount and syringe units for the vial and diluent you enter. It starts empty and does not suggest an amount. Open the full calculator

Inputs

What do you want to convert?
  1. mg

    Total amount printed on the vial label.

    Sizes sold:
  2. mL

    Volume of bacteriostatic water already in the vial.

  3. Check the unit. 1 mg = 1,000 mcg, so the wrong one is a 1,000x error.

  4. U-100

    Printed on the syringe wrapper. Results over this size are shown as invalid.

Result

Fill in steps 1 to 3 to see the arithmetic. Nothing here is a suggested amount.

Settings live in the address bar, so a pasted link reopens this calculator as you left it.

Educational arithmetic only. It does not choose an amount for you and is not medical or dosing advice. Verify every calculation independently.

Storage and stability

Dry powder (lyophilized)

TemperatureFreeze for long term storage, or 2 to 8 short term
Shelf lifeMany months when frozen
NotesKeep dry and out of light. If you have an approved product, follow its own storage instructions.

After mixing

Temperature2 to 8 (refrigerated)
Shelf lifeAbout 2 to 4 weeks
NotesDo not freeze after mixing. Discard if cloudy or discolored.

General storage and stability guide

COA and purity notes

Common adulterantsunderdosed or mislabeled research vials, research semaglutide sold without the controls of the approved product, the wrong salt form sold as the active drug, giving less real drug than the label suggests
MislabelingThere are FDA approved products made to pharmaceutical standards. Research or compounded vials are not held to the same controls, so a recent third party COA matters. Watch for a salt form listed at the same mg as the active drug, which means less real semaglutide.
NotesSemaglutide has approved versions (Ozempic, Wegovy, Rybelsus). Research or compounded material is not the same product.

How to read a COA

Sources

  1. [1]Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1)

    New England Journal of Medicine 2021 (opens source in a new tab)· Randomized trial

  2. [2]Long-term weight loss effects of semaglutide in obesity without diabetes in the SELECT trial

    Nature Medicine 2024 (opens source in a new tab)· Randomized trial

  3. [3]Semaglutide and cardiovascular outcomes in patients with type 2 diabetes (SUSTAIN-6)

    New England Journal of Medicine 2016 (opens source in a new tab)· Randomized trial

  4. [4]Semaglutide prescribing information and drug overview

    U.S. FDA / Drugs.com 2024 (opens source in a new tab)· Regulatory record

Last reviewed 7 July 2026 · editorial status: reviewed