> For the complete documentation index, see [llms.txt](https://docs.rplpeptides.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.rplpeptides.com/docs/guides/peptide-troubleshooting-guide.md).

# 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 |

***

© 2026 RPL Peptide

rplpeptides.com


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