RetaCalc
Protocol library
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Semaglutide

A GLP-1 receptor agonist used in several authorised medicines. Formulation, indication and route are product-specific and must not be treated as interchangeable.

Evidence context, not a personal protocol

Quantities below reproduce their stated source context—label, human study, laboratory work or educational guide. They do not assess suitability, product equivalence or individual risk.

Wegovy injection label

Weekly label quantities

The line reproduces the adult Wegovy injection escalation stages. It does not apply to Ozempic, Rybelsus or unlicensed vial products.

Evidence source
Maximum study quantityChoose the maximum shown by the evidence line. Any earlier point can be selected below for its arithmetic.

Assigned weekly quantities

Select a point for its calculation examples
  1. Weeks 1 to 4
    0.25 mg
  2. Weeks 5 to 8
    0.5 mg
    +0.25 mg after 4 weeks
  3. Weeks 9 to 12
    1 mg
    +0.5 mg after 4 weeks
  4. Weeks 13 to 16
    1.7 mg
    +0.7 mg after 4 weeks
  5. Week 17
    2.4 mg
    +0.7 mg after 4 weeks
    Label maintenance quantity; no treatment end week is specified.

Vial-aware arithmetic

Reconstitution examples, up to 3 mL

Choose the vial quantity and BAC water first. The diagram and results below update for the selected 0.25 mg study quantity. Higher-strength vials may naturally land outside the 20-30 unit band.

Vial quantity

Choose the quantity printed on the vial.

BAC water added

Use 1, 2 or 3 mL, or enter a custom volume up to 3 mL.

Open the full reverse calculator
Three millilitre research vial, diluent vial and capped U-100 syringe on an ink-blue surface
One small vial, one measured diluent volume and one U-100 scale. The arithmetic connects all three.
BAC water selected
3 mL

Basic example limit: 3 mL maximum. Check the actual vial and product-specific limits.

1 mL BAC
2.5 units

resulting U-100 draw

Concentration
10 mg/mL
BAC added
1 mL
2 mL BAC
5 units

resulting U-100 draw

Concentration
5 mg/mL
BAC added
2 mL
3 mL BAC
7.5 units

resulting U-100 draw

Concentration
3.333 mg/mL
BAC added
3 mL

Shown in the diagram. Closest of these examples to 25 units.

Formula: draw units = selected mg × BAC mL ÷ vial mg × 100. The 20-30 unit band is a measurement reference, not a recommendation. Results are mathematical examples, not preparation instructions.

Dosage and protocol evidence

Each card states what the quantities are based on. A third-party or animal schedule is not a validated human dose.

Regulatory LabelSubcutaneousOnce weekly
Adults meeting the authorised Wegovy indication

0.25 mg weekly for weeks 1-4, then 0.5 mg, 1 mg and 1.7 mg in successive four-week stages before 1.7 mg or 2.4 mg maintenance

This is the adult Wegovy injection label schedule. Other semaglutide products, indications and routes use different instructions.

View source
Community GuideSubcutaneous in reportsWeekly; extended intervals are experimental
online research community maintenance reports

Reports describe 0.25-0.5 mg or 0.5-1 mg subcutaneously weekly, with occasional experimental 10-14-day intervals

These are non-label maintenance and microdosing anecdotes. They do not alter the four-week label escalation stages or establish a validated taper; raw/incretin-mimetics/im-semaglutide.md and refined/34-im-semaglutide-channel.md:58-64.

View source
Community GuideSubcutaneous in reportsWeekly; slower-than-label titration in some reports
authenticated research-forum (Peppys) weight-loss reports

Subcutaneous 0.25 mg weekly start stepping up roughly every four weeks toward the 2.4 mg standard maximum, with an experienced member advocating a slower-than-label microdose ramp near 500 mcg every couple of weeks; a clinical triple dose of 7.2 mg weekly is noted, and many switch to or stack with tirzepatide once semaglutide plateaus around 6-7 months

Forum provenance from an authenticated archive with usernames omitted. These are non-label community reports; reconstitution and unit confusion is common, quantities conflict, and the archive keeps the GLP-1-only semaglutide separate from tirzepatide. They are community provenance, not label instructions.

View source

Evidence summary

Semaglutide has a large clinical evidence base, but the evidence is tied to specific regulated formulations and participant populations.

Formulation matters

Do not infer equivalence between an authorised pen or tablet and a research vial. Concentration calculations cannot establish identity, purity, sterility or bioequivalence.

Community provenance (Peppys)

An authenticated research-forum archive records subcutaneous semaglutide anchored on a 0.25 mg weekly opening dose, stepped up about every four weeks toward the 2.4 mg standard maximum, with an experienced member advocating a slower-than-label microdose ramp near 500 mcg every couple of weeks. A clinical triple dose of 7.2 mg weekly is discussed, and the dominant strategic theme is switching to or stacking with tirzepatide once semaglutide plateaus around six to seven months. The same archive notes frequent reconstitution and unit confusion and keeps the GLP-1-only semaglutide separate from tirzepatide. Usernames are omitted and figures are logged as community provenance without endorsement; these reports do not alter the label schedule above.

Warnings and contraindications

Different semaglutide products have different indications, formulations and instructions.
Authorised labels contain serious warnings and contraindications requiring clinical assessment.

Contraindications reported by the source

Personal or family history of medullary thyroid carcinoma for relevant US products
Multiple Endocrine Neoplasia syndrome type 2 for relevant US products
Organised research bench with labelled storage tray, vial rack, notebook and thermometer
A clean workspace supports traceability. It does not establish sterility.

Shared across protocols

Supplies and general handling

Keep the universal checklist short. Product-specific labelling and source documentation always take priority over a general guide.

Research vial

Select the labelled vial quantity used in the calculation.

View Peppys vial

Bacteriostatic water

Use only a diluent appropriate to the research method and formulation.

View Peppys BAC water

U-100 measuring syringe

Use a new sterile device for every entry. Source locally.

Source locally

Wipes and sharps container

Plan clean handling and immediate sharps disposal. Source locally.

Source locally

Storage follows the label

Do not apply a universal refrigerator rule. Follow the product, diluent and study documentation for temperature, light and expiry.

Use sterile equipment once

CDC injection-safety guidance calls for a new sterile needle and syringe for each injection and entry into a medication container.

Stability is formulation-specific

Do not infer a post-mixing lifetime from BAC water alone. Discard material when identity, integrity or sterility is in doubt.

General references: CDC injection safety, NHS medicine storage and DailyMed BAC water labelling.