Beyond-Use-Date Calculator
Work out a conservative use-by date for a reconstituted peptide from the date you mixed it and how you store it. The maths runs in your browser.
What a beyond-use date means
A beyond-use date (BUD) is how long a medicine stays safe and effective after you open or mix it - which is different from the manufacturer's expiry date on the sealed vial. Once a peptide is reconstituted, temperature is the biggest factor in how long it lasts. The windows here are deliberately conservative: 28 days refrigerated follows the USP-797 standard for a preserved multi-dose vial, room temperature is treated as same-day, and freezing is for single-use aliquots only.
Keep reconstituted vials in the body of the fridge at 2-8 degrees C, not the door where the temperature swings. Never refreeze a thawed aliquot - the ice crystals damage the peptide. Many peptides stay stable longer than these windows, but without testing your specific batch the conservative date is the safe one to work to.
Beyond-use date FAQ
Is this the same as the expiry date on the vial?
No. The expiry date applies to the sealed, unmixed product. The beyond-use date starts when you reconstitute it and is usually much shorter.
Can I freeze a reconstituted peptide to make it last longer?
Only as single-use aliquots at -20 degrees C, and never refreeze a thawed one. Repeated freeze-thaw cycles degrade the peptide. This is an approximate long-term window, not a guarantee.
What if it looks cloudy or has particles?
Discard it, regardless of the date. Cloudiness, discolouration or floating particles mean the solution should not be used.