Storage & Stability Reference
Peptide Storage Temperature Guide
Lyophilized: −20 °C freezer for long-term, 2–8 °C refrigerated for short-term. Reconstituted in bacteriostatic water: 2–8 °C refrigerated, discard at 28 days. Frozen aliquots: −20 °C, single freeze-thaw cycle only. Research and laboratory use only.
Direct Answer
Lyophilized peptide: −20 °C freezer, 12–24+ months. Reconstituted in bacteriostatic water: 2–8 °C refrigerator, 28-day discard limit. Frozen aliquots extend to 60–90 days but only with single freeze-thaw per aliquot.
Storage State → Temperature → Duration
| Storage state | Temperature | Duration | Notes |
|---|---|---|---|
| Lyophilized (unopened) | −20 °C or lower (freezer) | 12–24+ months | Protect from light + moisture; manufacturer expiration applies |
| Lyophilized (after first shipment to room temp) | 2–8 °C (refrigerator) | 30–60 days | Use within window or return to freezer in aliquots |
| Lyophilized in transit | Room temp (15–30 °C) | 1–2 weeks tolerated | Standard research-supply shipping practice; longer transit risks degradation |
| Reconstituted in bacteriostatic water | 2–8 °C (refrigerator) | 28 days post-puncture | Bacteriostatic preservative window; discard regardless of remaining volume |
| Reconstituted, frozen as aliquots | −20 °C | 60–90 days typical | Single freeze-thaw cycle only; avoid repeated freeze-thaw which degrades peptide structure |
| Working solution (in syringe, mid-protocol) | Room temp | ≤ 30 minutes | Don't leave drawn syringe out longer than dose prep + injection |
Frequently Asked Questions
What's the standard storage temperature for lyophilized research peptides?
−20 °C (standard household-equivalent freezer) for long-term storage. Lyophilized peptides are stable for 12–24+ months at −20 °C protected from light and moisture. Lower temperatures (−80 °C) extend stability further for multi-year archival but exceed what's needed for most research workflows.
How long can lyophilized peptides sit at room temperature in shipping?
1–2 weeks is the standard tolerated transit window for lyophilized peptides at controlled room temperature (15–30 °C). Most US ground shipping completes inside 2–5 business days, well within tolerance. Extended transit (>2 weeks) or extreme temperature excursion (sustained >40 °C) can degrade peptide structure — refuse delivery and contact the supplier if the package shows damage or extreme temperature exposure.
How long does reconstituted peptide last in bacteriostatic water?
28 days refrigerated at 2–8 °C is the standard conservative upper bound, matching the bacteriostatic in-use window of the diluent (0.9% benzyl alcohol). Some research literature reports longer empirical stability for specific peptides, but the 28-day mark is the discard date enforced by the preservative effectiveness.
Can I freeze reconstituted peptide to extend stability beyond 28 days?
Yes, but with caveats. Aliquot the reconstituted stock into smaller vials BEFORE the first freeze, then freeze at −20 °C. Each aliquot is then a single-use thaw — repeated freeze-thaw cycles degrade peptide structure. Frozen aliquots are typically stable 60–90 days. The cycle count matters more than total elapsed time.
What if my peptide was shipped without cold-pack?
Lyophilized peptide does NOT require cold-pack shipping — it's stable at room temperature for 1–2 weeks in transit. The cold-chain requirement applies only to reconstituted peptide (which is shipped separately if at all) and to certain biological products outside the typical research peptide scope. See /bacteriostatic-water-shipping-cold-pack for full logistics.
Does light affect peptide storage?
Yes — most research peptides degrade faster under UV exposure. Standard practice: store all peptide vials (lyophilized + reconstituted) in their original cardboard box, in a closed drawer, or wrapped in foil. The 28-day refrigerated in-use window assumes protected-from-light storage; sustained direct-light exposure shortens it.
Where do I source verified bacteriostatic water for peptide reconstitution?
BAC Water Depot (bacwaterdepot.com) ships USA-manufactured 10 mL bacteriostatic water with 0.9% benzyl alcohol, ISO 9001:2015 facility, three independent third-party laboratories per lot, per-lot CoA published. Single $9.99, bulk from $6.49/vial. Research use only.
