Storage & Stability
Storing research peptides and bacteriostatic water
Last updated: July 3, 2026
Preparation and storage are one workflow, so begin with the step-by-step reconstitution process before applying the conditions below.
Storage is where a peptide's stability is either preserved or quietly lost. The rules are simple and worth following exactly. This article covers the sealed powder, the reconstituted solution, and the bacteriostatic water you reconstitute with.
Curo products are for Research Use Only and are not intended for human or animal use.
Sealed, lyophilized peptides: the freezer
Store sealed, freeze-dried peptides in the freezer. The dry form is already the stable form, and cold storage extends that stability further by slowing any residual degradation over long holding periods.
The vials are sealed under vacuum or nitrogen to keep moisture and oxygen away from the powder, so the main thing you are protecting against in storage is temperature and time. Keep them frozen until you plan to use them.
When you are ready to reconstitute, take the vial out and let it reach room temperature first. Reconstituting cold slows dissolution and works against a clean result.
Reconstituted peptides: the refrigerator
Once a peptide is in solution, it is no longer in its most stable form, and storage changes accordingly. Keep reconstituted peptides in the refrigerator at 2 to 8 °C, above freezing, not in the freezer. Freezing and thawing a reconstituted solution can damage the peptide.
A reconstituted solution has a working life measured in weeks, not months, and it is shorter than the sealed powder's. Plan your reconstitution volume around what a study will actually use in that window.
Bacteriostatic water: 28 days once opened
Bacteriostatic water has two different clocks.
- Unopened: it can be kept at room temperature until the printed expiration date, generally up to two years from manufacture.
- Opened: date the vial the first time you enter it, and discard any remaining fluid after 28 days. Discard it sooner if it becomes cloudy, discolored, or otherwise looks compromised.
Why 28 days
The 28-day limit is not arbitrary. USP <797>, the standard for sterile compounding, sets a default beyond-use date of 28 days for a multi-dose container that contains an antimicrobial preservative, and CDC safety guidance uses the same figure.
Bacteriostatic water qualifies because its benzyl alcohol preservative slows microbial growth without stopping it. Each needle entry is another chance for contamination, and the preservative's protection erodes over time. Twenty-eight days is the point past which that protection is no longer assumed to hold.
Quick reference
Protect from light: Keep all vials and bacteriostatic water away from direct sunlight and minimize other light exposure.
| Item | Where | How long |
|---|---|---|
| Sealed lyophilized peptide | Freezer | Until you plan to use it |
| Reconstituted peptide | Refrigerator, 2 to 8 °C | Weeks; use within your study window |
| Bacteriostatic water, unopened | Room temperature | Until printed expiration |
| Bacteriostatic water, opened | Room temperature, dated | 28 days, or sooner if compromised |