Handling, storage & documentation

Reconstituting lyophilised material

The powder cake is fragile and the peptide is easier to damage than most people expect. The sequence that protects it:

• Let the vial reach room temperature before opening — condensation on cold glass introduces water you did not measure.
• Direct the diluent stream against the glass wall, never onto the cake.
• Swirl gently. Do not shake and do not vortex; mechanical shear degrades peptides.
• Wait for the cake to dissolve on its own rather than agitating it.

Use bacteriostatic water unless your protocol requires otherwise. Once in solution, store at 2–8 °C.

Storage windows and stability

Lyophilised material is stable for extended periods at −20 °C when it stays sealed and out of light. Once reconstituted the clock starts:

• Peptides: 2–8 °C, typically 30 days.
• Recombinant proteins: 2–8 °C, typically 14 days — they are markedly more sensitive to freeze–thaw.
• Glutathione: use promptly. It oxidises readily in solution.

Avoid repeated freeze–thaw cycles of reconstituted material. Aliquot at the point of reconstitution if you will be drawing from it repeatedly.

How to read a certificate of analysis

A COA is only useful if it corresponds to the vial in your hand. What to check, in order:

• Lot number. It must match the label. If it does not, the document describes different material.
• Purity method. Ours is RP-HPLC, area percent at 214 nm. A percentage with no method behind it means very little.
• Identity. Confirmed by ESI mass spectrometry against expected molecular weight — this is what rules out a substituted compound.
• Date. A certificate from a lot you did not receive tells you nothing about yours.

Browse the COA archive →

What “99%+ purity” does and doesn’t mean

It is a statement about relative abundance under one analytical method, not a guarantee of anything else. A 99% RP-HPLC result means the target compound accounts for 99% of the UV-absorbing material detected at 214 nm.

It does not speak to sterility, endotoxin load, residual solvents or elemental impurities — those are separate tests. If your work depends on any of them, ask us before ordering rather than assuming a purity figure covers it.

Appearance: what is normal

Most lyophilised peptides present as a white to off-white cake. Some variation is expected and is not a defect:

• GHK-Cu is deep blue. The copper complex is coloured. A white GHK-Cu vial would be the anomaly.
• A cake that has shifted or partly collapsed in transit is cosmetic — fill weight is verified gravimetrically per lot.
• A cracked seal, a compromised stopper, or a lot number that does not match the certificate are not cosmetic. Contact us within 7 days.

What “research use only” obliges you to

These materials are laboratory reagents. They are not drugs, foods, cosmetics or medical devices, they have not been evaluated for safety in humans or animals, and they must not be used in or on either.

Purchasing confirms you are a qualified buyer handling them in a research setting, in a jurisdiction where that is lawful, and that you accept responsibility for safe handling, storage and disposal. We cannot advise on dosing or administration, and we will not make an exception on request.