Free GLP-1 / Tirzepatide / Retatrutide Calculator – Exact Units, Reconstitution & Titration Math

Last updated August 2026 · Free · No signup required · Mobile-friendly for research use

This free GLP-1 calculator is built specifically for research compounds such as Semaglutide, Tirzepatide and Retatrutide. Enter your vial size, bacteriostatic water volume and target dose to receive the precise insulin-syringe units, concentration and volume to draw. The page also includes common research titration schedules, concentration tables and detailed worked examples so you can plan multi-week protocols with confidence.

How GLP-1 reconstitution and unit math works

Research vials of Semaglutide, Tirzepatide and Retatrutide arrive as lyophilized powder. After adding bacteriostatic water the concentration is simply:

Because these compounds are typically dosed in full milligrams (or half-milligram steps) rather than micrograms, the calculator works directly in milligrams. A 10 mg vial reconstituted with 2 mL of BAC water yields 5 mg/mL. A 2.5 mg dose therefore requires 0.5 mL, which is exactly 50 units on a standard U-100 insulin syringe.

Common research titration schedules (educational reference)

Clinical and research literature frequently uses gradual dose escalation to improve tolerability. The schedules below are compiled from publicly discussed research protocols and are provided for educational arithmetic only. They are not medical recommendations.

Tirzepatide-style weekly titration (research context)

• Weeks 1–4: 2.5 mg once weekly
• Weeks 5–8: 5 mg once weekly
• Weeks 9–12: 7.5 mg once weekly
• Weeks 13–16: 10 mg once weekly
• Thereafter: 12.5 mg or 15 mg if tolerated and protocol continues

Retatrutide-style research escalation (illustrative)

• Starting range often discussed: 0.5–2 mg weekly
• Step-wise increases every 4 weeks
• Common research maintenance band: 4–8 mg weekly (higher doses appear in some trial arms)

Semaglutide research context

• Typical research starting points: 0.25 mg or 0.5 mg weekly
• Escalation every 4 weeks toward 1 mg, 1.7 mg or 2.4 mg ranges depending on the protocol

Concentration and unit reference tables

The tables below show common vial-and-water combinations and the resulting units for popular research doses. Click any row in the live calculator above to load similar values.

10 mg vial + 2 mL BAC water = 5 mg/mL

* Doses above 100 units require a larger syringe or a split injection.

40 mg vial + 2 mL BAC water = 20 mg/mL (popular high-concentration research setup)

Retatrutide 10 mg vial examples

Detailed worked examples

Storage, stability and handling notes for GLP-1 research peptides

• Lyophilized (unreconstituted) powder is best stored frozen or at least refrigerated and protected from light and moisture.
• Once reconstituted with bacteriostatic water, keep the vial refrigerated at 2–8 °C (36–46 °F).
• Most research sources indicate reconstituted GLP-1-class peptides remain usable for approximately 28 days when properly refrigerated and handled with sterile technique.
• Avoid repeated freeze–thaw cycles after reconstitution; ice crystals can damage the peptide.
• Protect from direct light. Amber vials or foil wrapping are commonly used.
• Discard any solution that becomes cloudy, discolored, or contains visible particles.

Choosing BAC water volume for GLP-1 compounds

Higher concentration (less water) produces smaller injection volumes, which many researchers prefer for weekly doses above 5 mg. Lower concentration (more water) spreads the dose over more syringe units and can make fine titration easier. A practical target is a draw volume between 10 and 75 units on a U-100 syringe so the mark is easy to read and the injection volume remains comfortable.

Syringe selection tips

• 1 mL (100-unit) syringe – most versatile for doses from ~10–80 units.
• 0.5 mL syringe – excellent resolution for mid-range doses.
• 0.3 mL syringe – best when the calculated volume is under ~0.25 mL.

All standard insulin syringes use the U-100 scale (100 units = 1 mL), so the unit number returned by the calculator is the mark you aim for regardless of barrel length.

Frequently Asked Questions

Free GLP-1 / Tirzepatide / Retatrutide calculator · No registration · Updated August 2026 · Accurate unit conversion for research use