How to Read a COA

Learn how to verify peptide quality through Certificate of Analysis documents.

What is a COA?

A Certificate of Analysis (COA) is a document provided by a testing laboratory that verifies the identity, purity, and potency of a compound. For peptides, this is the single most important quality indicator you should evaluate before purchasing.

Key Elements of a Peptide COA

1. Purity Percentage (HPLC)

High-Performance Liquid Chromatography (HPLC) measures purity by separating the peptide from impurities. Look for:

>98% purity: Excellent — research grade

95-98% purity: Good — acceptable for most purposes

<95% purity: Concerning — significant impurities present

2. Identity Confirmation (Mass Spectrometry)

Mass spectrometry (MS or LCMS) confirms the molecular weight of the peptide matches what it should be. This verifies you're getting the right compound, not something substituted.

3. Third-Party vs. In-House Testing

Third-party COAs: Conducted by an independent laboratory — much more credible

In-house COAs: Conducted by the vendor themselves — potential conflict of interest

4. Date of Analysis

COAs should be recent. Look for testing within the last 12-18 months. Very old COAs may not reflect current batch quality.

Red Flags to Watch For

No COA provided at all

COA is an image with no laboratory information

Purity listed as "99.9%" for every single product (suspiciously perfect)

No laboratory name, accreditation number, or contact information

COA date is years old

Reputable Testing Laboratories

Look for COAs from recognized labs such as:

Janoshik Analytical

Intertek

SGS

Eurofins

Bottom Line

Never purchase peptides from a vendor who cannot provide a legitimate COA from an identifiable third-party laboratory. The COA is your primary protection against underdosed, mislabeled, or contaminated products.