The Two States: Lyophilized vs. Reconstituted
Before we discuss expiration, we must define the state of your peptide.
- Lyophilized (Freeze-Dried) Powder: This is how your peptides arrive from wlaustralia. Through a process called lyophilization, water is removed under a vacuum, leaving behind a stable “puck” of protein. In this state, the peptide is like a hibernating bear: its metabolic activity is near zero.
- Reconstituted (Liquid) Solution: Once you introduce a diluent, the peptide “wakes up.” It is now vulnerable to heat, light, and bacterial contamination. This is where the clock starts.
Pro Tip: Always store your unmixed, lyophilized vials in the freezer (around -20°C) for long-term storage of 12–24 months. If you plan to use them within a few weeks, the refrigerator (2–8°C) is sufficient.
The Mixing Medium: BAC Water vs. Sterile Water
The most common frustration for researchers is a solution that “goes bad” before the vial is empty. The culprit is often the choice of water.
Bacteriostatic (BAC) Water: The Security Guard
Consider BAC water the “security guard” of your vial. It contains 0.9% benzyl alcohol, which acts as a preservative to inhibit the growth of bacteria.
- Shelf Life: Approximately 28–30 days when refrigerated.
- Usage: Ideal for multi-dose vials where you will be drawing solution over several weeks.
Sterile Water: The One-Hit Wonder
Sterile water is exactly what it says: pure and sterile, but with no preservative.
- Shelf Life: 24–48 hours (maximum 72 hours) when refrigerated.
- Usage: Only for single-use applications. Once the seal is broken, any microscopic bacteria introduced by the needle will multiply rapidly because there is no benzyl alcohol to stop them.
The Strategy: Always use BAC water for peptides like Vilon or Epitalon if your research protocol spans more than two days.
