📅 Vial Duration Calculator
Find how long your reconstituted vial lasts and check whether it fits inside the 28-day safe-use window.
The 28-Day Expiry Rule
Reconstituted peptides stored with bacteriostatic water have a finite shelf life of 28 days when refrigerated at 2–8°C. This is not an arbitrary limit — it reflects the lifespan of the benzyl alcohol preservative in BAC water. After 28 days, bacterial inhibition decreases and peptide degradation accelerates. Using reconstituted peptide beyond this window introduces both efficacy and safety risk.
This calculator tells you exactly how many days your vial will last at your dosing frequency. If it exceeds 28 days, it shows how much peptide you lose to waste and suggests whether to use a smaller vial, split the vial, or reconstitute in stages.
A 10 mg BPC-157 vial, dosed at 500 mcg twice daily.
- Total mcg: 10 mg × 1,000 = 10,000 mcg
- Daily usage: 500 mcg × 2 = 1,000 mcg/day
- Duration: 10,000 ÷ 1,000 = 10 days ✅ within 28 days
- Total doses: 10,000 ÷ 500 = 20 injections
Vial Duration Calculator
Enter your vial size, dose per injection, and how often you inject.
| Checkpoint | Status | Doses used | Remaining |
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Refrigerate at 2–8°C. Never freeze. Label every vial with the reconstitution date. Discard after 28 days regardless of remaining volume.
Vial Duration — Frequently Asked Questions
Why exactly 28 days?
The 28-day limit reflects the effective lifespan of the 0.9% benzyl alcohol preservative in bacteriostatic water. After this period, its bacteriostatic action diminishes, and the peptide itself degrades more rapidly through hydrolysis at amino acid bonds. Some peptides may remain structurally intact beyond 28 days, but since potency cannot be verified at home, the 28-day rule applies universally as a conservative safety standard.
Can I freeze a reconstituted vial to extend the shelf life?
No. Freeze-thaw cycles cause ice crystal formation that mechanically damages peptide chains. You can freeze the unreconstituted lyophilised powder (sealed dry vial) for 12–24 months, but once reconstituted with BAC water, commit to using it within 28 days. If a vial will last longer than 28 days, reconstitute only part of it and keep the rest as dry powder.
My vial lasts 45 days — what should I do?
You have three options: (1) Use a smaller vial — if a 2 mg vial fits within 28 days, buy those instead of 5 mg. (2) Reconstitute in stages — add enough BAC water to cover only 28 days of doses, and store the rest as dry powder in the sealed vial. (3) Increase your dose slightly within the safe protocol range to consume the vial before expiry. Option 2 is cleanest and most common.
How do I store a reconstituted vial correctly?
Store upright in the back of a standard refrigerator (2–8°C / 35–46°F) — not the door, which fluctuates in temperature. Keep away from direct light. Label with: peptide name, concentration, reconstitution date, and 28-day expiry date. Store in a dedicated clean container away from food. Never allow even brief freezing.