How to Store Research Peptides: Lyophilized, Reconstituted and Pre-Filled

Lyophilized vials: refrigerate at 2–8 °C short term, freeze at −20 °C long term, keep dry and dark. Reconstituted solutions: refrigerate, use within the COA window, or aliquot and freeze once. Pre-filled pens: refrigerate, never freeze, keep capped and in the carton. Heat, light, moisture and repeated freeze–thaw are the enemies.

Why peptides degrade

Three processes account for most peptide loss in storage. Hydrolysis — water breaking peptide bonds — needs water, which is why the dry lyophilized form is so much more stable than a solution. Oxidation affects methionine, cysteine and tryptophan residues in particular; Semax, with an N-terminal methionine, is a typical example. Aggregation is driven by heat, shear and concentration. Thermal and photolytic stress on synthetic peptides has been characterised directly [1], and the drying science that produces a stable lyophilized cake is its own field [2].

Lyophilized vials

• Short term (weeks): 2–8 °C, in the original carton, away from light.
• Long term (months or more): −20 °C. The lyophilized cake tolerates freezing well.
• Keep dry. The stopper is the moisture barrier; never leave a vial open. Let a cold vial reach room temperature before opening so condensation does not form inside.
• Light. Amber or carton-shielded is best; UV accelerates oxidation.

Reconstituted solutions

• Refrigerate at 2–8 °C immediately after reconstitution.
• Use within the window on the COA. Bacteriostatic water's preservative limits microbial growth; it does not stop chemical degradation.
• For longer holds, aliquot and freeze once at −20 °C in single-use volumes. Every freeze–thaw cycle costs material; avoid refreezing a thawed aliquot.
• Label with concentration and the date of reconstitution.

Pre-filled research pens

• Refrigerate, 2–8 °C, in the carton.
• Never freeze. Freezing a solution in a pen can damage both the peptide and the device.
• Keep capped between uses and return to the refrigerator promptly.
• Light-sensitive contents — the NAD+/B12 pen in particular — should stay in the carton.

In transit

APX Labs ships in temperature-aware packaging and dispatches same or next business day so material spends the minimum time in transit; see shipping. On receipt, refrigerate immediately and check the lot number against the COA.

By compound

• GHK-Cu: the copper complex is stable as a solid; in solution the blue colour should persist — fading suggests loss of copper coordination.
• IGF-1 LR3: a ~9 kDa protein; more aggregation-prone than short peptides, so avoid shear and freeze–thaw.
• Semax: N-terminal methionine — protect from oxidation; keep dark.

Laboratory handling guidance for research reagents only. APX Labs products are for research use only.

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