How Peptide Blends Are Tested, and How to Read Their Certificates

Some research materials combine two or more peptides in a single vial — BPC-157 with TB-500, for example, or Selank with Semax. Testing a blend is not the same as testing a single compound, and a certificate for a blend should look different from one for a single peptide. Knowing what to expect makes it much easier to tell a thorough report from a thin one.

Each component needs its own number

A blend is only as good as the amount of each ingredient in it. A vial labelled as 10 mg of one peptide plus 10 mg of another could contain 14 mg of the first and 6 mg of the second and still weigh the right total. That is why a useful blend certificate reports content separately for every component, in milligrams, rather than a single combined figure.

Our certificate for the BPC-157 and TB-500 blend, for instance, lists each peptide on its own line with three vial results for each. That tells you both the ratio and how consistently the vials were filled.

How the laboratory separates the components

On an HPLC trace, each peptide in the blend leaves the column at a different retention time, so a blend shows one major peak per component rather than a single dominant peak. The laboratory identifies which peak belongs to which peptide and quantifies each against its own reference standard.

This only works when the peaks are well separated. Two components that elute close together can overlap, and the method has to be adjusted to pull them apart before either can be measured reliably. It is one reason blends generally cost more to test properly than single compounds.

What “purity” means for a blend

For a single peptide, purity is the main peak’s share of the total peak area. For a blend, that definition breaks down: the second component is not an impurity, but it is certainly a second peak. So blend certificates commonly report:

• Content per component — usually the most important figure;
• No single overall purity figure, or purity stated for each component separately if the method allows it.

A blend certificate that shows one headline purity figure, such as “99% pure”, with no explanation of how the second component was treated is worth a closer look. See how to read an HPLC chromatogram for how area-percent purity is calculated.

Three-component and four-component blends

The more components a blend contains, the harder a complete analysis becomes. Every additional peptide needs its own reference standard, its own peak on the trace and its own quantification, and small peptides can be difficult to retain and resolve alongside larger ones. For complex blends it is normal for a certificate to quantify the major components and to be explicit about anything it does not quantify. What is not normal is silence: a report should make clear which components were measured.

Reading a blend certificate: a checklist

1. Is every labelled component named in the results?
2. Is content given in milligrams for each component, not only as a total?
3. Are several vials reported, so fill consistency can be judged?
4. Is any purity figure explained — per component, or not reported?
5. Does the lot code match the lot being sold, and can the report be verified with the laboratory? See how to verify a lab report yourself.

The certificates for our blends are listed with every other lot on the lab results page. For background on why content and purity are separate measurements, see net peptide content.

Materials supplied by BMS Labs are for laboratory research use only and are not for human or veterinary use.