How to Calculate How Many Doses Are Left in Your Peptide Vial

The Basic Formula

Doses remaining = Total peptide in vial ÷ Dose per injection

Let's say you have:

First, convert to the same unit:

You can perform 40 injections from this vial.

Working with Pre-Reconstituted Vials

Many vials come pre-filled with a stated concentration. For example:

Label reads: "1,000 mcg/mL, 10 mL vial"

This means:

If your dose is 100 mcg:

Calculating Doses When You Reconstitute Yourself

You receive a lyophilized (powder) vial and must add BAC water. The label states:

After reconstitution:

If your dose is 250 mcg (0.25 mL drawn per injection):

Each injection draws 0.25 mL, so 20 doses × 0.25 mL = 5 mL total (the entire vial).

The Dead Space Problem

Here's the catch: syringes have "dead space"—the needle, hub, and plunger cannot deliver all the liquid drawn. On average:

This means if you draw 1 mL, roughly 0.05-0.1 mL stays in the syringe and never enters your body. This reduces your usable doses.

Practical calculation:

This is why serious users often get a few extra doses' worth when calculating reorder quantities.

The Practical Tracking Method

Don't rely on math alone—track actual usage:

Create a simple log with columns:

Example:

```

Date | Dose (mL) | MCG | Total Used | Est. Remaining

4/15 | 0.25 | 250 | 250 | 9,750

4/16 | 0.25 | 250 | 500 | 9,500

4/17 | 0.25 | 250 | 750 | 9,250

```

After 30 days of daily 250 mcg doses, you'll have used approximately 7,500 mcg, leaving 2,500 mcg. At that point, 10 more doses remain—time to reorder.

Reordering Timeline

Most users order when 2-3 weeks of doses remain. This accounts for:

Example timeline:

Multi-Vial Protocols

If you're rotating between compounds:

This prevents simultaneous re-orders and optimizes shipping costs.

Accounting for Spillage and Errors

In practice, some peptide is lost to:

Budget an extra 10-15% when ordering. So if calculations show you need 100 doses, order enough for 110-115 doses.

Digital Tracking

Tools like MyProtocolStack let you:

This removes guesswork and ensures you're never without supply during a protocol.

Quick Reference: Common Scenarios

5 mg vial, 250 mcg daily dose, 250 mcg/mL concentration:

10 mg vial, 100 mcg daily dose, 100 mcg/mL concentration:

2 mg vial, 0.5 mg twice daily, 1 mg/mL concentration:

Taking 60 seconds to calculate remaining doses ensures your protocol never falters due to poor planning.

This article is for informational and educational purposes only and does not constitute medical advice. Always consult a licensed healthcare provider before starting, adjusting, or stopping any peptide protocol. MyProtocolStack is a protocol tracking and blood work analysis platform — it is not a medical device and does not provide clinical recommendations.