Peptide shelf life calculator
Calculate peptide expiry based on storage condition and date received or reconstituted. Covers lyophilized and reconstituted peptides across all storage conditions.
Peptide stability is determined by the physical state of the compound (lyophilized vs reconstituted) and the storage conditions. Understanding the difference between these states is essential for maintaining potency throughout a research protocol.
Lyophilized (freeze-dried) peptides are highly stable because the removal of water eliminates the primary pathway for chemical degradation — hydrolysis. Most lyophilized peptides retain full potency at room temperature for 12-24 months in sealed vials. Refrigeration extends this further. Freezing provides maximum stability for long-term storage. Lyophilized peptides can tolerate ambient temperatures during shipping without significant degradation.
Reconstituted peptides are dramatically less stable. Once dissolved in bacteriostatic water, the peptide is exposed to water molecules, temperature fluctuations, and potential microbial growth despite the benzyl alcohol preservative. The general guideline is 28 days at 2-8°C (refrigerator). Some peptides are more stable: tirzepatide and retatrutide, as larger structured molecules, maintain potency longer. Smaller peptides like sermorelin and GHRP-6 are more fragile.
Never freeze reconstituted peptides. The formation of ice crystals physically disrupts the peptide's molecular structure, causing irreversible aggregation and denaturation. A frozen and thawed reconstituted peptide may appear visually unchanged but has significantly reduced biological activity.
Key signs of degradation: cloudiness or turbidity, visible particles or flocculation, unusual color change, or an unexpected odor. Any of these indicate the solution should be discarded.
This calculator applies published stability data for common peptide storage conditions.
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July 3, 2027
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Estimated shelf life: ~12 months under refrigerator (2–8°c) conditions. Avoid freeze-thaw cycles for reconstituted peptides. Always use bacteriostatic water. Peptide degradation accelerates above 8°C once reconstituted.
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Frequently asked questions
How long does reconstituted BPC-157 last in the refrigerator?+
Reconstituted BPC-157 in bacteriostatic water is typically stable for 28-42 days at 2-8°C. BPC-157 is a relatively small peptide (15 amino acids) and degrades faster than larger, more structurally complex molecules. For maximum potency, use within 28 days of reconstitution. Some researchers reconstitute smaller vials more frequently rather than maintaining one large vial for months.
Can I freeze reconstituted peptides to extend shelf life?+
No — freezing reconstituted peptides is contraindicated. Ice crystal formation physically disrupts the peptide's three-dimensional structure through mechanical force, causing irreversible aggregation. The peptide may appear unchanged after thawing but biological activity is significantly reduced or eliminated. If long-term storage is needed, keep the peptide in lyophilized form (which can be frozen safely) and reconstitute only what you need for the current protocol.
How should I store lyophilized peptides for long-term stability?+
For storage up to 12 months: refrigerator (2-8°C) in the original sealed vial provides excellent stability. For storage beyond 12 months or maximum stability: freezer (-20°C) in the sealed vial. When moving from freezer to use, allow the vial to come to room temperature before opening to prevent condensation from entering the vial. Lyophilized peptides can tolerate brief room temperature exposure without significant degradation.
How do I know if my reconstituted peptide has gone bad?+
Key visual indicators: cloudiness or turbidity (a clear solution becomes opaque or milky), visible particulate matter or flocculation (floating particles or aggregates), color change (most peptide solutions are colorless to very slightly yellow — strong yellow or brown coloring is abnormal), and unusual odor. Any of these signs indicate degradation and the solution should be discarded. If in doubt, discard and reconstitute fresh — the cost of a new vial is low relative to the cost of a failed research protocol.
Does bacteriostatic water actually extend shelf life compared to sterile water?+
Yes, significantly. Sterile water without preservative allows bacterial and fungal growth within 24-48 hours after puncture. Bacteriostatic water with 0.9% benzyl alcohol inhibits microbial growth, extending the safe use period to 28 days in a refrigerated multi-dose vial. The benzyl alcohol does not affect peptide stability — it acts specifically on microbial membranes. Using sterile water for multi-dose reconstitution carries meaningful infection risk.
Research background
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