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cat. no. SEMAGLUTIDE

Semaglutide

GLP-1 receptor agonist (incretin mimetic)

also: Ozempic / Wegovy / Rybelsus

At a glance

Half-life~7 (range ~6-7) days
Typical reconstitution5 / 10 mg vial + 1-2 mL BAC water
Studied dosestudy0.25 (start, weeks 1-4, not for glycemic control) then 0.5 then 1 then 2 (max) mg
Storage (mixed)Community guidance for compounded vials: refrigerate at 2-8C (36-46F) and use within 28 days of mixing; never freeze a reconstituted solution.

What it is

Semaglutide is a lab-made version of GLP-1, a hormone your gut releases after you eat. It nudges the pancreas to release more insulin and less glucagon, but only when blood sugar is already high, which is why it rarely causes lows on its own. It also slows stomach emptying and quiets appetite signals in the brain - lowering blood sugar (Ozempic, Rybelsus) and driving substantial weight loss at higher doses (Wegovy). A fatty-acid side chain lets it grab onto albumin in the blood, so one dose keeps working for about a week instead of minutes.

Dose ranges

Study-backed ranges carry a source you can open. Community ranges are widely reported but not clinically established - treat them as what people do, not as advice.

Type 2 diabetes, injectable (Ozempic)

study

0.25 (start, weeks 1-4, not for glycemic control) then 0.5 then 1 then 2 (max) mg

once weekly, subcutaneous; hold each step at least 4 weeks

Chronic weight management, injectable (Wegovy)

study

0.25 then 0.5 then 1 then 1.7 then 2.4 (maintenance) mg

once weekly, subcutaneous; each step held 4 weeks

Type 2 diabetes, oral tablet (Rybelsus)

study

3 (days 1-30, not for glycemic control) then 7 (days 31-60) then 14 (day 61+, max) mg

once daily, oral, empty stomach 30 minutes before food

Community microdosing for weight loss / GI tolerability (off-label)

community

0.125-0.25 (weeks 1-4), 0.25-0.5 (weeks 5-8), 0.5-0.75 (weeks 9-12) mg

once or twice weekly

Reconstitution & storage

No FDA-approved semaglutide vial exists for patient reconstitution - Ozempic and Wegovy are prefilled pens or syringes and Rybelsus is an oral tablet. These figures reflect compounded/research-vial community practice only, not an approved product. A common community ratio: 5 mg vial + 2 mL bacteriostatic water = 2.5 mg/mL, which measures easily on a U-100 insulin syringe. Always use bacteriostatic water made for injection, never tap or plain distilled water.

Lyophilized

FDA-approved products are liquid, not freeze-dried, so there is no FDA spec for lyophilized powder. Community/compounding guidance reports unreconstituted powder stable ~12-24 months at -20C (0F).

Reconstituted

Community guidance for compounded vials: refrigerate at 2-8C (36-46F) and use within 28 days of mixing; never freeze a reconstituted solution.

Run the numbers in the calculator

Common stacks

CAGRILINTIDE

Interactions & cautions

Contraindicated with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2), based on thyroid C-cell tumors in rodents (FDA labels). Acute pancreatitis has been reported with GLP-1 agonists; watch for persistent severe abdominal pain. Because semaglutide slows gastric emptying it can delay absorption of oral medications, and Rybelsus increased levothyroxine exposure by 33%. Combining with insulin or a sulfonylurea raises hypoglycemia risk, so those doses are often reduced. The Wegovy label recommends discontinuing at least 2 months before a planned pregnancy.

Questions people ask

What happens if I miss a weekly semaglutide dose?

Per the FDA Ozempic label, take the missed dose within 5 days of the missed day. If more than 5 days have passed, skip it and resume on your regular day - do not double up.

How long does semaglutide stay in the body after stopping?

Its half-life is about 1 week, so per the FDA Wegovy label it is still measurably present for roughly 5 to 7 weeks after the last dose - which is also why the label advises stopping at least 2 months before a planned pregnancy.

Who should not take semaglutide?

It is contraindicated in anyone with a personal or family history of medullary thyroid carcinoma (MTC) or MEN 2, per the Ozempic, Wegovy, and Rybelsus labels, based on thyroid tumors seen in rodent studies.

Is microdosing semaglutide an official protocol?

No. It is a community and telehealth practice of staying at or below the approved 0.25 mg starting dose, marketed as a gentler titration. There is no FDA-approved microdosing schedule for any GLP-1 drug.

Sources

  1. [1]OZEMPIC (semaglutide) injection - FDA Prescribing InformationlabelFDA-approved T2D titration (0.25 to 0.5 to 1 to 2 mg weekly), pen/syringe storage temperatures, MTC/MEN2 contraindication, pancreatitis warning, missed-dose guidance, and interactions.
  2. [2]WEGOVY (semaglutide) injection - FDA Prescribing InformationlabelFDA-approved weight-management titration (0.25 to 2.4 mg weekly), ~1 week half-life with drug present 5-7 weeks after last dose, pregnancy discontinuation guidance.
  3. [3]RYBELSUS (semaglutide) tablets - FDA Prescribing InformationlabelOral titration schedule (3 mg then 7 mg then 14 mg max) and a 33% increase in levothyroxine exposure when co-administered.
  4. [4]Clinical Pharmacokinetics of Semaglutide: A Systematic Review (Yang & Yang, 2024) PMID 38952487studySubcutaneous semaglutide half-life is approximately 1 week (145-168 hours across pooled studies), dose-proportional AUC/Cmax.
  5. [5]How to Reconstitute Semaglutide (PeptideDeck, community guide)communityCommunity/compounding reconstitution practice: 5-10 mg vials with 1-2 mL bacteriostatic water, refrigerated and used within 28 days.

What we could not verify

DrugBank and the primary NEJM CagriSema paper were paywalled/403 and not used; FDA labels plus the Yang & Yang 2024 PMC review cover the same pharmacology with primary sourcing. Reconstitution vial sizes rest on a single community source. Everything tagged community is off-label/unregulated practice, not clinical guidance.