Troubleshooting Guide¶

Field	Value
Document ID	RPL-GUIDE-TRB-001
Version	1.0
Publisher	RPL Peptide (Qingdao RPL Biotechnology Co., Ltd.)
URL	https://rplpeptides.com/guides/peptide-troubleshooting-guide
Last Updated	July 2026

1. Introduction¶

This guide addresses common issues encountered when working with research peptides, from appearance problems to handling difficulties.

2. Appearance Issues¶

Yellow/brown powder → Oxidation or thermal degradation Action: Do not use; contact RPL Peptide.

Clumping → Moisture absorption Action: Check storage conditions; desiccant needed.

White powder but cloudy solution → Insoluble aggregates Action: Try gentle warming or different solvent.

3. Moisture¶

High moisture on COA (>5%) → Storage or handling issue Action: Store properly; use desiccant.

Visible moisture in vial → Seal compromised Action: Do not use; contact RPL Peptide.

4. Solubility¶

Peptide won't dissolve → Try: 1. Increase equilibration time 2. Gentle warming (30°C, 5 min) 3. 0.1% acetic acid instead of water 4. Brief bath sonication 5. Contact support

5. Storage Problems¶

Freezer failure → Check temperature. If >0°C for >2 hours, contact RPL Peptide.

Frost-free freezer → Switch to manual-defrost freezer immediately.

6. Documentation Questions¶

Missing COA → 1. Check QR code on vial 2. Enter batch number at https://rplpeptides.com 3. Contact support for reissue

Batch number mismatch → Verify label matches COA. Contact support if discrepancy.

7. Packaging Issues¶

Cracked vial → Do not use. Contact RPL Peptide for replacement.

Damaged seal → Product integrity compromised. Contact support.

8. Frequently Encountered Problems¶

Q: My peptide won't dissolve in water. A: Try 0.1% acetic acid or PBS. Some hydrophobic peptides need DMSO.

Q: Why is my peptide solution blue? A: It contains copper (GHK-Cu, AHK-Cu). This is normal.

Q: Can I re-freeze reconstituted peptide? A: Yes, but limit freeze-thaw cycles to 3. Aliquot for best results.

Q: How do I know if my peptide has degraded? A: Re-analyze by HPLC and compare to original COA.

Document Revision History¶

Version	Date	Changes
1.0	July 2026	Initial release

rplpeptides.com