How should I store lyophilized peptides?

Lyophilized (freeze-dried) peptides should be stored at -20°C (freezer) for long-term storage of up to 1–2 years. They can be stored at 4°C (refrigerator) for up to 3–6 months. Always protect from light and moisture.

How long does a reconstituted peptide last?

Reconstituted peptides stored at 2–8°C (refrigerator) in bacteriostatic water are typically stable for 4–6 weeks. Do not freeze reconstituted peptides — ice crystal formation can degrade the peptide structure.

Yes. Peptides degrade through oxidation, hydrolysis, and microbial contamination. Signs of degradation include discoloration, cloudiness that won't clear, precipitate formation, or reduced efficacy. Proper storage prevents premature degradation.

Storage

Peptide Storage: How to Store Research Peptides

Improper storage is the most common cause of peptide degradation outside of reconstitution errors. These are the rules that matter.

Rule #1 — Lyophilized: freeze at -20°C for long-term. Reconstituted: refrigerate at 4°C, use within 4–6 weeks. Never freeze a reconstituted vial.

By State

Lyophilized vs. Reconstituted

-20°C / 4°C

Lyophilized (Freeze-Dried) — Unopened Vial

Shelf Life: 1–2 Years

Store in freezer at -20°C for maximum longevity. Short-term storage (up to 3–6 months) is acceptable at 4°C in a standard refrigerator. Keep away from light and moisture. Do not open until ready to reconstitute.

2–8°C

Reconstituted in BAC Water — Open Vial

Shelf Life: 4–6 Weeks

Refrigerate immediately after reconstitution. Keep in the original vial. Most peptides remain stable for 4–6 weeks. Do not freeze — ice crystals can disrupt peptide structure. Protect from light.

The Rules

Do's and Don'ts

Refrigerate reconstituted vials at 2–8°C

Freeze lyophilized vials at -20°C

Keep vials in the original box

Label with reconstitution date

Swab stopper before each draw

Don't

Freeze reconstituted vials

Leave vials at room temp

Expose to direct light/sunlight

Shake — always swirl

Use past 6 weeks after reconstitution

Signs of Degradation

When to Discard a Vial

Discard a reconstituted peptide vial if you notice any of the following:

✗ Persistent cloudiness after 15 minutes at room temp

✗ Visible particles or precipitate that won't dissolve

✗ Yellow or brown discoloration (clear is normal)

✗ More than 6 weeks since reconstitution

FAQ

Common Questions

Can I freeze a reconstituted peptide vial?

No. Freezing a reconstituted vial causes ice crystals to form, which can physically disrupt the peptide's molecular structure. Only lyophilized (powder) vials should be frozen. Reconstituted vials must be refrigerated at 2–8°C.

How long do peptides last at room temperature?

Not long. Most peptides degrade significantly within 24–72 hours at room temperature. Always refrigerate reconstituted vials and minimize time out of the fridge during use.

Does light affect peptides?

Yes. UV light can break peptide bonds through photodegradation. Store vials in their original opaque boxes or wrap in aluminum foil. Avoid leaving vials on windowsills or under fluorescent lights.

Should I label my vials?

Always. Write the reconstitution date and concentration on the label before refrigerating. This prevents accidentally using an expired vial and helps you track doses per vial.

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