# Cost per dose: the math for reconstituted vials

> Work out what one dose really costs from a reconstituted vial: doses per vial, cost per dose and cost per month — the arithmetic with worked examples.

Source: https://glp-1-app.com/learn/cost-per-dose/

Education · arithmetic only · not medical advice

## Cost per dose: the math for reconstituted vials

Vial prices are quoted per vial; budgets happen per month. Three divisions connect them — here's each one, with a worked example.

### Step 1 — doses per vial

**Doses per vial = vial strength (mg) ÷ your dose (mg).** A 5 mg vial at a 0.5 mg dose → 10 doses. A 10 mg vial at 2.5 mg → 4 doses. Note what's _not_ in this formula: the bacteriostatic water. Adding more water dilutes the solution (you draw more units per dose) but the total drug in the vial — and therefore the number of doses — doesn't move.

### Step 2 — cost per dose

**Cost per dose = vial price ÷ doses per vial.** That $300, 5 mg vial at 0.5 mg per dose: $300 ÷ 10 = **$30 per dose**. The same vial at a 1 mg dose is $60 per dose — cost per dose scales directly with dose size, which is why the same vial can be cheap for one person and expensive for another.

### Step 3 — cost per month

**Cost per month = cost per dose × doses per month.** For weekly dosing, a month is about 4.35 weeks (52 ÷ 12), so: $30 per dose × 4.35 ≈ **$130/month**. Using 4 flat makes months look cheaper than they are — over a year that shortcut hides ~a full vial of spend.

### The gotcha: partial vials

Doses per vial rarely divide evenly. A 5 mg vial at 0.75 mg is 6 full doses with 0.5 mg stranded — you either waste it or your 7th dose is short. When comparing vial sizes, compare _usable_ doses (round down), not the raw division. The [calculator](https://glp-1-app.com/) does this rounding for you and shows the exact per-dose cost from your own numbers.

### Worked example, end to end

10 mg vial, $420, 2 mL of bac water, 1.25 mg dose: doses per vial = 10 ÷ 1.25 = **8** · cost per dose = 420 ÷ 8 = **$52.50** · monthly (weekly dosing) = 52.50 × 4.35 ≈ **$228**. The 2 mL of water never entered the math — it only determines that each dose is 25 units on a U-100 syringe.

Log shots, track doses per vial and expiry, and plan your taper — private by design.

Educational arithmetic only — not medical, pricing, or purchasing advice. Dose decisions belong to you and your prescriber; prices in examples are illustrative round numbers, not quotes.

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