How to Read a Peptide Blend COA

A blend puts two or more peptides in one vial, so its certificate of analysis has to answer more questions than a single-peptide report. This guide shows what to look for on a blend report, how the numbers relate, and which gaps are worth asking about.

What a blend is

A blend is one lyophilized (freeze-dried) vial containing more than one peptide, usually labeled with each component and its amount, for example “10mg / 10mg” or “50 / 10 / 10”. The label amounts are the intended content of each component. The total mass in the vial is higher, because a vial also contains excipients such as a bulking agent. See the peptide-to-excipient ratio guide.

Why blends are harder to read

A single-peptide report asks: is this the right molecule, and how pure is it? A blend report has to answer the same for several components at once, and also: are all the intended components present, and in what amounts?

What to look for

1. Every labeled component is identified. The report should show identity (mass spectrometry) results for each component, not just one. A component that is on the label but not on the report is a gap to ask about.
2. Separate peaks in the HPLC trace. In a blend, the chromatogram normally shows more than one main peak, one for each component. A reported “purity” figure for a blend can mean different things: the main peak’s share, the combined share of all expected peaks, or a per-component figure. Check which the report states, and see how purity is tested.
3. Component amounts. Look for a content or potency result per component, compared with the label. Purity and potency are different questions; see purity vs. potency.
4. Total mass and ratio. The peptide figure plus the excipient mass should be close to the stated total mass, and the ratio line should match. The peptide figure is the laboratory’s measured peptide mass; compare it with the label amounts, and ask the laboratory if it differs.
5. Lot number and laboratory. As with any report: the lot matches the vial, the laboratory is named and contactable, and the test date is plausible. See how to verify a peptide COA.

Worked example: checking a blend’s arithmetic

Two published BT Labs reports on our COA page are blends. They are shown only to illustrate the arithmetic.

Report	Total mass	Peptide : excipients	Check
BPC-157 / TB-500 blend, lot BPTB062026-01	98.7 mg	22.6 : 76 mg (1:3.4)	22.6 + 76 = 98.6 mg; 76 ÷ 22.6 = 3.36
CJC-1295 / Ipamorelin blend, lot CP082026-01	52.6 mg	11 : 41.6 mg (1:3.8)	11 + 41.6 = 52.6 mg; 41.6 ÷ 11 = 3.78

In both reports the numbers add up. Compare the peptide figure on each report with the component amounts on the vial label, and note whether the report explains any difference. If it does not, that is a fair question for the laboratory.

Common red flags on blend reports

• Only one component identified on a multi-component label.
• A single purity number with no explanation of what it covers.
• A chromatogram with only one peak for a vial labeled as a blend.
• A peptide figure in the ratio line that the report does not explain relative to the label amounts.
• Identical figures on different blends or lots. See COA red flags.

Questions to ask a supplier

1. How is the purity figure on this blend calculated: per component, or for the whole mixture?
2. Which tests identify each component?
3. Is there a content result for each component?

Blends we publish reports for

Each of these product pages shows the lot, laboratory, test date and HPLC purity beside the certificate: BPC-157 / TB-500, CJC-1295 / Ipamorelin, KLOW and GLOW.

See it on real reports

Our published certificates are on the COA page, including blends. Product pages for our blends show the lot, laboratory, test date and HPLC purity beside the certificate. More in the COA reading guide and the glossary.

All products are sold strictly for laboratory research use only. Not for human or veterinary use, and not a drug, food, or cosmetic.