How to store peptides

Peptides are fragile molecules, and how they are stored has a direct effect on whether they remain what the lab report says they are. The rules are simple, but they are different for sealed powder and for dissolved solutions, and a tropical climate raises the stakes.

The main enemies

Four things degrade peptides:

• Heat, which speeds up every chemical reaction that breaks a peptide down.
• Moisture, which lets those reactions happen.
• Light, which damages some peptides directly.
• Repeated temperature changes, particularly freezing and thawing a solution.

Good storage is simply about limiting all four.

Sealed, lyophilized powder

A sealed vial of freeze-dried powder is the most stable form a peptide takes. Most tolerate ordinary room temperature well while sealed and dry, which is why they can be shipped without refrigeration.

• Short term: a cool, dark, dry place is generally fine.
• Longer term: a refrigerator, and for very long storage, a freezer, slow degradation further.
• Before opening a cold vial: let it reach room temperature first. Opening or puncturing a cold vial in humid air draws condensation inside, and moisture is exactly what the powder needs to be kept away from.

Reconstituted solutions

Once a peptide is dissolved, the clock runs much faster.

• Refrigerate at 2–8 °C, in the main body of the fridge.
• Avoid the door, where temperature swings every time it opens.
• Avoid the back wall, where some fridges run cold enough to freeze.
• Do not freeze a reconstituted solution unless you have a specific reason and know the compound tolerates it. Ice crystals and repeated thawing damage peptides.
• Protect from light. Keep the vial in its box or wrap it in foil. Some compounds, such as Semax, are particularly sensitive to light.
• Label the vial with the date it was mixed and the volume added.

How long a solution lasts depends on the compound and the liquid used. We cover it in how long reconstituted peptides last.

What changes in Bali

Bali is hot and humid all year, and both conditions work against peptides.

Never leave vials in a car or on a scooter. The inside of a parked car in the tropical sun gets far hotter than the air outside. Even a short stop can expose a vial to temperatures well beyond what a solution tolerates.

Watch for power cuts. A fridge that loses power in Bali warms up quickly. If you lose power for an extended time, a reconstituted vial may be affected.

Humidity matters for powder. Keep sealed vials in their packaging and away from bathrooms and kitchens. Humidity is the main reason for letting a cold vial warm up before opening it.

Carry chilled. When a mixed solution has to travel, an insulated case with a cooling insert keeps it within range for the journey. Sealed powder can travel without one.

Signs a vial may have degraded

• A solution that has become cloudy or developed particles
• Powder that looks wet, sticky or syrupy
• A colour change you would not expect for that compound

Any of these is a reason not to rely on the vial.