Peptide Calculator — Reconstitution, Dosing & Microdosing Tools

Reconstitution Calculator

BAC water mixing · U-100 syringe visualizer

Vial size (mg)

BAC water to add (mL)

Desired dose per injection (mcg)

Enter in mcg (1 mg = 1000 mcg)

Results

U-100 insulin syringe · Standard protocol

Concentration

2.50

mg/mL

Volume/dose

0.10

Syringe units

10.0

IU (U-100)

Doses per vial

total doses

U-100 Syringe Visualizer 10.0 IU

0102030405060708090100 IU

Protocol steps

Sanitize

Wipe vial tops with 70% isopropyl alcohol swab.

Draw BAC water

Draw 2.00 mL of bacteriostatic water into your syringe.

Inject slowly

Inject the BAC water down the side of the peptide vial. Do not aim directly at the powder.

Swirl gently

Swirl (do not shake) until fully dissolved and clear.

Draw dose

Draw 0.10 mL (10.0 IU on syringe) for each 250 mcg dose.

Store

Refrigerate reconstituted vial at 2–8°C. Use within 28–30 days.

Common reconstitution examples

Peptide	Vial	BAC Water	Concentration	250mcg dose	Doses
BPC-157	5 mg	2 mL	2.5 mg/mL	10 IU (0.1 mL)	20
TB-500	10 mg	2 mL	5 mg/mL	5 IU (0.05 mL)	40
Semaglutide	5 mg	2 mL	2.5 mg/mL	10 IU (0.1 mL)	20
Tirzepatide	10 mg	2 mL	5 mg/mL	5 IU (0.05 mL)	40
Retatrutide	10 mg	2 mL	5 mg/mL	5 IU (0.05 mL)	40
Ipamorelin	5 mg	2 mL	2.5 mg/mL	10 IU (0.1 mL)	20

⚠️ Disclaimer: This calculator is for research and educational purposes only. Always verify calculations with a medical professional. Use single-use needles and dispose in a proper sharps container.

Half-Life & Accumulation

Drug accumulation curve over weeks

Compound

Half-life (hours)

Dose per injection (mg)

Dosing interval

Simulation duration (weeks)

Pharmacokinetic Analysis

Based on first-order kinetics

Peak (steady state)

—

Trough

—

Accumulation

—

× factor

Steady state

—

days

Clinical Insight

Loading…

Systemic Concentration Over Time Clearance model

Drug level

Steady state

Reference half-lives

Compound	Half-Life	Steady State	Accumulation	Dosing
Retatrutide	~144h (6 days)	~4–5 weeks	7×	Once weekly
Tirzepatide	~120h (5 days)	~3–4 weeks	5×	Once weekly
Semaglutide	~168h (7 days)	~4–5 weeks	8×	Once weekly
CJC-1295 DAC	~192h (8 days)	~5–6 weeks	9×	Once weekly
TB-500	~72h (3 days)	~2–3 weeks	2.3×	EOD / Weekly
BPC-157	~4h	~1–2 days	~1×	ED / BID
Ipamorelin	~2h	~12h	~1×	BID / TID

⚠️ Calculations based on first-order pharmacokinetic modeling. Individual metabolism varies. For research and educational purposes only.

GLP-1 Microdosing Schedule Generator

Compare once-weekly vs split-dose protocols — optimize peak/trough ratio

Step 1 — Select compound

Step 2 — Total weekly dose (mg)

Step 3 — Choose dosing frequency

Steady-State Metrics

Protocol B — Twice weekly

Metric	Value
Per-injection dose	—
Peak concentration (SS)	—
Trough concentration (SS)	—
Peak-to-trough ratio	—
Peak reduction vs 1×/week	—
Days to steady state	—

Weekly injection schedule

Tap a frequency above to see schedule

Plasma concentration comparison

⚠️ Critical Research Disclaimer: Microdosing GLP-1 agonists is not clinically studied. These calculations are based on pharmacokinetic modeling, not clinical trials. Always consult a licensed physician before altering any dosage or frequency.

Frequently Asked Questions

How much bacteriostatic water do I add to a peptide vial?

It depends on your target dose. A common approach: add 2 mL of BAC water to a 5 mg vial, giving you a 2.5 mg/mL (2,500 mcg/mL) concentration. At that concentration, a 250 mcg dose = 10 units on a U-100 insulin syringe. Use the reconstitution calculator above to find the exact ratio for your vial size and desired dose.

What syringe do I use for peptide injections?

Standard U-100 insulin syringes — 29 to 31 gauge, 0.5 mL or 1 mL capacity. The 100-unit markings correspond to 1 mL total volume. The reconstitution calculator above outputs your dose in "IU" which directly corresponds to the syringe tick marks.

How do I convert mcg to units on an insulin syringe?

Divide your target dose in mcg by the concentration (mcg per mL) to get the volume in mL, then multiply by 100 to get insulin syringe units. Example: 250 mcg ÷ 2500 mcg/mL = 0.1 mL × 100 = 10 IU. The reconstitution calculator does this automatically.

Why does drug level keep rising week after week with GLP-1s?

GLP-1 agonists like Semaglutide (~7 day half-life) and Retatrutide (~6 day half-life) are injected weekly, but your body hasn't fully cleared the previous dose before you inject again. Each dose adds on top of residual drug. This continues until the amount eliminated between doses equals the amount injected — called steady state. This is why slow titration (increasing every 4 weeks) is essential and why early doses feel different from later doses.

What is the benefit of split-dosing (microdosing) GLP-1s?

Splitting a weekly dose into 2–3 smaller doses throughout the week reduces the peak concentration immediately after injection. This flattened peak may reduce side effects like nausea, vomiting, and GI discomfort that spike in the first 24–48 hours. The tradeoff is more frequent injections. This approach is based on pharmacokinetic modeling — it has not been studied in clinical trials.

Can I use BAC water vs sterile water?

Use bacteriostatic water (BAC water) for multi-dose vials. It contains 0.9% benzyl alcohol which inhibits bacterial growth, allowing you to draw multiple doses from the same vial over 28–30 days. Sterile water has no preservative and is only suitable for single-dose use. Never use tap water or saline for peptide reconstitution.