The words on the catalog, defined.

An amino acid is a small organic molecule with an amine group at one end and a carboxylic acid group at the other, joined through a central carbon that carries a side chain. Twenty of them are the standard building blocks of every protein, and the side chain is what makes one different from another. A few lines on this catalog are single amino acids or their derivatives; most are chains of them. Every product page states which it is under Specification.

A peptide is two or more amino acids joined end to end by peptide bonds; an amino acid is one unit on its own. Chemists call a chain of up to about fifty residues a peptide and a longer, folded chain a protein, though the boundary is a convention rather than a rule. Length matters to a buyer for one practical reason: it is a large part of what sets the cost of a vial, which the pricing page explains.

Most of them, yes. Amino acids are the building blocks, and when they link into a chain that chain is a peptide; we use the word amino because it describes the chemistry accurately across the whole catalog, including the lines that are single amino acids, a dinucleotide or a small molecule. Every product page names the class of molecule in its first line. The full list is on the order list.

It means the material is supplied as a chemical reagent for laboratory research use only: not a drug, not a dietary supplement, not a food or cosmetic, and not FDA-approved for any use. The grade describes the intended use and the documentation that comes with the material, not a purity level. Who may buy it is set out under buyer eligibility.

Lyophilized means freeze-dried: the compound was frozen in solution and the ice removed under vacuum, leaving a dry cake in the vial. A dry cake under seal holds its identity in storage and transit far better than a solution does, which is why this catalog's peptide lines are supplied this way. What an intact cake looks like, and how to store it, is on the quality page.

It tells you what share of the material in that lot eluted as the main peak when the lot was run through high-performance liquid chromatography — a measure of how much of the sample is the named compound rather than related impurities. It is a figure about one tested lot, stated in the past tense, and it says nothing about identity on its own, which is why the same certificate also carries a mass-spectrometry result. Ask for the certificate through COA requests.

A certificate of analysis, or COA, is the laboratory report for one specific lot. It names the compound and the lot number, states the identity result from mass spectrometry, the purity result from HPLC, the appearance of the material and the endotoxin result, and carries the date of testing. Every certificate supplied through this site names a lot number that matches the vials it describes; how to read one line by line is covered in the COA guide.

A safety data sheet is the hazard-communication document for a chemical: composition, handling, storage, transport and disposal information in the standard sixteen-section format. It is available on request for any compound on the catalog, the same way a COA is, and a buyer who stores or handles the material at a workplace will usually need it on file. Request either document through COA and SDS requests.