How to store research peptides: lyophilised and reconstituted

Most of what's written about peptide quality is about the lab: purity, content, certificates. All of that describes the product on the day it was tested. What happens between then and the day it's used depends on how it's stored, and that part is down to whoever's holding the vial.

Lyophilised powder

Most research peptides are supplied lyophilised, meaning freeze-dried into a powder or "cake" at the bottom of a sealed vial. Taking the water out is what makes them stable enough to ship and store.

• —Long-term storage: −20°C, in a freezer.
• —Short-term storage: 2–8°C, in a fridge.
• —In transit: lyophilised peptides are generally stable at room temperature for the length of a normal postal journey, which is why they're posted without cold packs. That isn't a reason to leave them out once they arrive.

Once reconstituted

Once a lyophilised peptide is dissolved, it's much less stable than the dry powder. Reconstituted vials are kept at 2–8°C and used within 28 days. Freezing and thawing a solution can damage the peptide, which is why reconstituted vials shouldn't be refrozen.

Light, moisture and air

Temperature isn't the only thing that degrades peptides. Light can break some of them down, so vials are best kept in their box or somewhere dark. Moisture is the enemy of a dry powder: a vial taken straight from the freezer and opened will pull condensation in from the air. Letting a sealed vial come up to room temperature before it's opened avoids that.

What to check when a parcel arrives

• —Seals and flip-off caps are intact.
• —The powder is a solid cake or loose powder, not a sticky film or liquid.
• —Every vial has a legible label with the compound, strength and lot number.
• —The contents match your order, compound and strength.
• —Anything wrong is photographed, including the lot number, and reported straight away.

Bacteriostatic water

Unopened bacteriostatic water is normally stored below 25°C and protected from light, and discarded 28 days after first opening. We explain how it differs from sterile water in Bacteriostatic water vs sterile water.

Where the storage instructions live

Every Zenic Labs label carries its storage conditions on the back, next to the lot number, so the instructions stay with the vial. If anything here ever differs from the label on a product you've been sent, follow the label. Everything we sell is for laboratory research use only, and we can't advise on how it's used.