This article is for laboratory and research information only. All products referenced are supplied strictly for research use and are not for human or veterinary use.
Research peptides are generally supplied in one of two formats: freeze-dried powder in a sealed vial, or a ready-mixed solution in a pre-filled pen. Each has trade-offs for stability, convenience and storage. Here is how they compare.
Lyophilised (freeze-dried) vials
Lyophilisation removes water from a peptide by freezing it and then lowering the pressure so the ice sublimates. What's left is a dry powder or "cake" in a sealed vial.
- Stability: best of the two formats. Stored frozen at around -20°C, lyophilised peptides can stay stable for long periods.
- Flexibility: the lab chooses the solvent and volume, so it controls the final concentration. Our concentration calculator helps with this.
- Extra step: needs reconstitution with a suitable solvent such as bacteriostatic water.
Browse our peptide vials.
Pre-filled pens
Pre-filled pens contain the peptide already in solution, at a fixed concentration.
- Convenience: no reconstitution step, which saves time and removes a source of handling error.
- Consistency: the concentration is set at manufacture, so it is identical from pen to pen.
- Shorter shelf life: peptides in solution degrade faster than dry powder, so pens need refrigeration and have a shorter storage window.
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Side-by-side comparison
| Lyophilised vial | Pre-filled pen | |
|---|---|---|
| Form | Freeze-dried powder | Ready-mixed solution |
| Reconstitution needed | Yes | No |
| Long-term stability | Highest (frozen) | Lower (refrigerated) |
| Concentration control | Set by the lab | Fixed at manufacture |
| Best suited to | Longer study timelines, custom concentrations | Shorter studies, minimal preparation |
Peptides available in both formats
- BPC-157: vial / pen
- TB-500: vial / pen
- GHK-Cu: vial / pen
- NAD+: vial / pen
- MOTS-c: vial / pen
- KPV: vial / pen
- Tesamorelin: vial / pen
- Melanotan 2: vial / pen
FAQ
Do pre-filled pens need to be refrigerated?
Yes. Because the peptide is already in solution, pens should be kept at 2–8°C and protected from light.
Can lyophilised vials be stored at room temperature?
Briefly, for example in transit. For anything longer, refrigerate or freeze them. See do peptides need to be refrigerated?