How to choose a peptide supplier.
Research peptides are sold by many vendors, and a vial of white powder looks the same whatever is in it. What tells them apart is the paperwork behind the vial and whether it holds up when you check it. Here are seven checks to run before buying, and what a good answer looks like for each.
A report for the exact lot.
A Certificate of Analysis covers one lot. The lot number on the report should match the lot on the vial or the product page; a report with no lot number, or one that never changes, says nothing about the vial you receive. How to read a peptide COA walks through a report line by line.
A named lab you can verify.
The report should name the laboratory that ran the tests. Many independent labs let anyone check a report against their own record in under a minute, and that check matters because a PDF can be edited or borrowed. How to verify a peptide COA shows how.
Identity, not just purity.
HPLC purity says how much of the peptide material is the target sequence, not which sequence it is. Identity is a separate test, usually mass spectrometry against the expected mass, and a report with only a purity number answers half the question. How peptides are tested covers each result.
How much is in the vial.
Purity is not quantity. A published analysis of peptide vials bought from three online shops, each sold as 10 mg, measured between 4.3 and 8.8 mg. A good report states the measured amount next to the labeled one, and net peptide content shows how much of the powder is peptide once counterions and water are counted.
Endotoxin and sterility.
Endotoxin from Gram-negative bacteria can change the results of cell and animal experiments even in trace amounts; the LAL test measures it in endotoxin units. A sterility test shows whether anything grows in culture over at least 14 days. See endotoxin testing and sterility testing.
The molecule spelled out.
A supplier should state the sequence, any caps such as Ac- or -NH2, the formula and the molecular weight, so the identity result can be checked against something. Trade names are not standardized: TB-500, for one, has been used for more than one molecule. The sequence is what counts, and the peptide molecular weight calculator turns it into an expected mass.
Honest labeling.
Research peptides are laboratory reference materials. A supplier selling them for research should label them research use only and keep human-use claims off the page; sales copy that promises results in people is a warning sign on its own. What RUO means covers the label.
How Helion answers them.
Helion's reports come from ILS Laboratories, name their lot and carry a Verify at ILS link in the COA Portal. Each covers identity, HPLC purity and endotoxin, and the peptide reports add measured content, sterility and heavy metals; reports publish per lot as testing completes. Every compound page lists its sequence, formula and molecular weight, and every product is labeled for research use only.
Specs and storage by compound.
Questions (5)
How do I know if a peptide supplier is legit?
Ask for the Certificate of Analysis for the exact lot, check it with the lab that issued it, and make sure it covers identity by mass spectrometry as well as HPLC purity, plus endotoxin and, for peptides, sterility.
What should a peptide COA include?
The lab's name, the lot number, identity by mass spectrometry, HPLC purity, and ideally measured content, endotoxin, sterility and heavy metals.
Is HPLC purity enough to trust a peptide?
No. It shows how much of the peptide material is the target sequence, not which molecule it is or how much is in the vial.
Can a peptide COA be faked?
A PDF can be edited or borrowed, which is why checking it against the issuing lab's own record matters.
Where does Helion test its peptides?
At ILS Laboratories. Each published report has a Verify at ILS link in the COA Portal.
Published studies (4)
- Characterization of Synthetic Peptide Therapeutics Using Liquid Chromatography-Mass Spectrometry: Challenges, Solutions, Pitfalls, and Future Perspectives
- Synthetic pharmaceutical peptides characterization by chromatography principles and method development
- Identification and characterization by LC-UV-MS/MS of melanotan II skin-tanning products sold illegally on the Internet
- Residual endotoxin contaminations in recombinant proteins are sufficient to activate human CD1c+ dendritic cells
Citations from PubMed for reference. They describe the compound in the literature, not any Helion lot, and nothing here is guidance on use.