At NXPeptides, quality assurance isn’t an afterthought — it’s the foundation of everything we do. Every peptide in our catalog undergoes a comprehensive, multi-stage testing protocol before it ever reaches you. We maintain a minimum purity standard of 98% and provide full documentation with every order.
Our Testing Philosophy
We believe that trust begins with trust in materials. That’s why we’ve built a quality assurance program that prioritizes transparency, consistency, and scientific rigor. Every compound we sell is subjected to multiple independent analyses, and we make those results available to every customer.
Our QA program is designed around three core principles:
- Independence: All analytical testing is performed by accredited third-party laboratories to eliminate bias
- Completeness: We test for purity, identity, sterility, and endotoxin levels on every batch
- Transparency: Full Certificates of Analysis are available for every product, every batch
Third-Party Testing
NXPeptides partners with independent, ISO 17025-accredited analytical laboratories to verify the quality of every batch we produce. By using third-party testing exclusively, we ensure that our quality claims are objective and verifiable.
Our testing partners employ state-of-the-art instrumentation and validated analytical methods that meet or exceed current industry standards. Each laboratory maintains rigorous internal quality controls and participates in regular proficiency testing programs.
Testing Parameters
Every batch of peptide produced by NXPeptides is evaluated across four critical parameters. The table below outlines our testing methodology and acceptance criteria:
| Parameter | Method | Acceptance Criteria | Purpose |
|---|---|---|---|
| Purity | HPLC (High-Performance Liquid Chromatography) | ≥ 98.0% | Confirms the compound meets minimum purity standards and is free of significant impurities |
| Identity | Mass Spectrometry (MS) | Molecular weight within ± 0.1% of theoretical | Verifies the molecular identity of the peptide matches its intended structure |
| Sterility | USP <71> Sterility Testing | No growth detected | Ensures the product is free from microbial contamination |
| Endotoxin | LAL (Limulus Amebocyte Lysate) Assay | < 0.25 EU/mL | Screens for bacterial endotoxins that could compromise product safety |
Certificate of Analysis (CoA)
Every NXPeptides product ships with a Certificate of Analysis — a detailed document that reports the results of all testing performed on that specific batch. Our CoAs include:
- Product name, catalog number, and batch/lot number
- HPLC purity percentage with chromatogram reference
- Mass spectrometry results with observed vs. theoretical molecular weight
- Sterility testing results
- Endotoxin screening results
- Date of manufacture and expiration date
- Storage and handling recommendations
- Name and accreditation details of the testing laboratory
CoAs are included with your shipment and can also be requested at any time by contacting our support team.
Purity Standards
NXPeptides maintains a strict minimum purity threshold of 98% for all products in our catalog. Many of our peptides consistently test above 99% purity. Any batch that falls below our acceptance criteria is rejected and never released for sale.
Our purity analysis is conducted using reversed-phase HPLC with UV detection at 220nm wavelength. This method provides highly accurate and reproducible purity measurements and is considered the gold standard for peptide analysis in both academic and pharmaceutical settings.
Manufacturing Standards
Our peptides are synthesized using solid-phase peptide synthesis (SPPS) — the most widely validated method for producing high-purity peptides. Our manufacturing partners operate in controlled cleanroom environments and follow strict standard operating procedures (SOPs) at every stage of production.
Key manufacturing controls include:
- Raw material qualification and incoming inspection
- In-process quality checks during synthesis
- Post-synthesis purification via preparative HPLC
- Lyophilization (freeze-drying) under controlled conditions
- Aseptic filling and sealing in sterile vials
- Final QC release testing before distribution
Storage & Handling
Proper storage is essential to maintaining peptide integrity. NXPeptides takes storage seriously at every stage of the supply chain:
At Our Facility
All inventory is stored in temperature-monitored cold storage between 2°C and 8°C (refrigerated) or -20°C (frozen), depending on the specific compound. Environmental monitoring systems track temperature and humidity 24/7, with automated alerts for any deviations.
During Shipping
Every order ships in insulated packaging with gel ice packs to maintain cold chain integrity during transit. Our packaging has been validated to maintain safe temperatures for up to 48 hours under standard shipping conditions.
After Delivery
Upon receipt, we recommend storing lyophilized (powder) peptides at -20°C or colder. Reconstituted peptides should be stored at 2–8°C and used within the timeframe specified on the product label. Avoid repeated freeze-thaw cycles, as these can degrade peptide integrity.
Email: support@nxpeptides.com
Phone: +1 (518) 327-4392
Hours: Monday – Friday, 9AM – 6PM EST