How to Read a Peptide Certificate of Analysis

A certificate of analysis is the only document standing between you and a vial of unknown powder. Every peptide vendor will tell you their product is pure. The COA is where that claim either gets verified by an independent lab or falls apart under scrutiny. This page breaks down what each section means and which red flags should make you walk away from a purchase.

What Is a Certificate of Analysis

A certificate of analysis (COA) is a document issued by an analytical laboratory that reports the results of testing performed on a specific batch of a substance. For peptides, the COA covers purity, identity, and safety screening. The lab runs standardized tests, records the data, and publishes results tied to a lot number so the buyer can match the document to the specific vial they purchased.

A legitimate COA is not a marketing document. It is a technical report from a lab with no financial stake in whether you buy the product. When a COA comes from the seller's in-house lab rather than an independent third party, the credibility drops because the incentive to report favorable results is obvious.

Key Sections of a Peptide COA

HPLC Purity Data

High-performance liquid chromatography (HPLC) is the standard method for measuring peptide purity. The technique separates the target peptide from impurities by passing it through a reversed-phase C18 column. A detector at UV 214-220 nm measures absorbance of the peptide bond as each component elutes. Purity is calculated as the area under the main peak divided by total peak area, expressed as a percentage. Methods are validated to ICH Q2(R1) and USP guidelines for chromatographic testing. Research-grade peptides should be 95% or higher. High-purity products reach 99% or above.

Mass Spectrometry Identity

While HPLC tells you how pure the sample is, mass spectrometry tells you what the sample actually is. The test measures molecular weight by ionizing the peptide and detecting mass-to-charge ratios. For BPC-157, the expected molecular weight is approximately 1419.5 Da. A result confirming this value within the instrument's accuracy range verifies the vial contains the correct peptide rather than a truncated fragment or different compound entirely.

Endotoxin Screening

Endotoxins are bacterial cell wall fragments that cause fever and inflammation. The limulus amebocyte lysate (LAL) test detects them by exposing a reagent derived from horseshoe crab blood to the sample. Acceptable levels for research peptides are typically below 0.1 EU/mg. Not every COA includes endotoxin screening because it adds cost, but its presence provides evidence the manufacturing process was clean.

Appearance and Solubility

These basic quality checks describe the physical appearance of the lyophilized peptide (typically a white to off-white powder) and its solubility. While less critical than purity and identity, these entries confirm the lab actually handled and observed the sample rather than generating numbers from a template.

Red Flags on a COA

A COA missing any three of the items above should be treated as unreliable. A COA missing five or more is not a COA at all.

How Our Reviewed Sellers Handle COAs

Real Peptides publishes per-lot COAs from two independent laboratories: Freedom Diagnostics and Kovera. These documents report HPLC purity of 99% or higher, confirm molecular identity via mass spectrometry, and include endotoxin screening results below 0.1 EU/mg. Each COA ties to a specific lot number and includes the lab's name, contact information, test date, and methodology. The documents are available on the product page before purchase.

Peptide God does not publish COAs on its product pages. No testing laboratory is named, no purity data is presented, and no analytical documentation is available for review. This does not necessarily mean the product is impure, but it means the buyer has no independent evidence to evaluate. For a full seller comparison, see our trusted BPC-157 sellers page.