How to store lyophilized peptides in the lab

Store a lyophilized, or freeze-dried, peptide the way its label says: usually cold, always dry, away from light, in a sealed container. Medicines regulators describe peptides as generally kept refrigerated or frozen, and as powders that draw water from the air. So the two things to control are temperature and moisture, and the label is the first place to look for both.

This page describes laboratory practice for materials: temperature, light, moisture, containers and labels. It says nothing about preparing or using any material on a person or an animal. The quotations come from guidance written for medicines; we quote them to explain good storage, not to say any product is made or kept to them.

Start with the label

Health Canada's guidance on storing and transporting drugs opens its storage list with the simplest rule:

"Store all drugs according to the conditions described on the label of the product."

Health Canada, GUI-0069, section 5.1, retrieved 12 October 2026.

The international guide for active ingredients, ICH Q7, says the label is where special conditions belong:

"Special transport or storage conditions for an API or intermediate should be stated on the label."

ICH Q7, section 10.22, retrieved 12 October 2026.

If a container has no storage condition on it, that is a gap worth raising with the supplier before the material goes on a shelf.

Temperature: refrigerated or frozen

The European Medicines Agency's guideline for synthetic peptides describes the usual storage for peptides as medicines' active ingredients:

"Generally, to prevent or minimise degradation, peptides are stored under refrigerated (5°C ± 3°C) or frozen conditions (-20°C ± 5°C)"

European Medicines Agency, Guideline on the Development and Manufacture of Synthetic Peptides, section 4.7.1, retrieved 12 October 2026.

In plain words: refrigerated means about 2 to 8 degrees Celsius, and frozen means about minus 15 to minus 25. These are the conditions that guideline describes for medicines; the right condition for a given material is the one on its label.

Moisture: the quiet problem

Freeze-drying removes water, but the powder takes it back from the air. The EMA guideline's sentence on this begins:

"Peptides are often very hygroscopic powders, therefore appropriate precautions against moisture uptake"

European Medicines Agency, Guideline on the Development and Manufacture of Synthetic Peptides, section 4.5, retrieved 12 October 2026.

And on packaging:

"For hygroscopic powders, appropriate desiccant or storage under inert atmosphere could be considered if relevant."

European Medicines Agency, Guideline on the Development and Manufacture of Synthetic Peptides, section 4.6, retrieved 12 October 2026.

Good laboratory habits follow from this: keep containers sealed and open them as little as possible. Water also changes what a weighed amount contains; see peptide content vs purity.

Light, contamination and the container

The EMA guideline asks medicines' makers to take account of:

"any temperature and/or light sensitivity of the active substance"

European Medicines Agency, Guideline on the Development and Manufacture of Synthetic Peptides, section 5, retrieved 12 October 2026.

Health Canada's storage guidance covers light alongside temperature:

"Ensure any controls for conditions that are specified on the label (e.g. temperature, humidity, light, etc.) are in place."

Health Canada, GUI-0069, section 5.1, retrieved 12 October 2026.

ICH Q7 states the general aim of storage:

"Materials should be handled and stored in a manner to prevent degradation, contamination, and cross-contamination."

ICH Q7, section 7.40, retrieved 12 October 2026.

The EMA guideline adds a line on packaging:

"The container closure system should be suitable"

European Medicines Agency, Guideline on the Development and Manufacture of Synthetic Peptides, section 4.6, retrieved 12 October 2026.

In practice: keep the original sealed vial or container, store it in the dark or in an opaque box, and do not move powder into containers that were not made for it.

Order and rotation

Two more lines from ICH Q7 describe tidy storage for any stock of materials:

"Materials stored in fiber drums, bags, or boxes should be stored off the floor"

ICH Q7, section 7.41, retrieved 12 October 2026.

"should normally be controlled so that the oldest stock is used first."

ICH Q7, section 7.42, retrieved 12 October 2026.

The second line is about stock rotation: when several lots of the same material are on hand, the oldest goes first. Dates matter for that; see how long peptides last.

A short storage checklist

1. Read the label's storage condition before the material goes on a shelf.
2. Store at that condition: for peptides, usually refrigerated or frozen.
3. Keep containers sealed, dry and dark.
4. Keep the original container and its label.
5. Rotate stock so the oldest lot is used first.
6. Record the storage temperature; see temperature control and records.

None of this says whether a material may be bought or sold in Canada; for that, read are peptides legal in Canada?.

The handling series also covers shelf life, temperature records and labels. Get the free library updates by email.