A peptide is a short chain of amino acids joined by amide (peptide) bonds. The boundary between a peptide and a protein is informal; chains under roughly fifty residues are usually called peptides. The compounds in a research catalog range from tripeptides such as GHK and KPV to forty-residue analogs of gut and pituitary hormones.
How they are made
Nearly all commercial research peptides are produced by solid-phase peptide synthesis (SPPS). The chain is assembled one residue at a time on an insoluble resin, with protecting groups controlling which reactive sites are available at each step. When the sequence is complete it is cleaved from the resin, purified by reversed-phase high-performance liquid chromatography (RP-HPLC), checked for identity by mass spectrometry, and freeze-dried.
Modified peptides add steps. Fatty-acid chains (as on semaglutide and tirzepatide), unnatural amino acids such as Aib or D-amino acids, N-terminal acetylation and C-terminal amidation are all introduced during or immediately after assembly and are part of why two peptides of similar length can differ widely in cost.
Why lyophilized
Peptides in solution hydrolyse, oxidise and aggregate over time. Removing the water by freeze-drying (lyophilization) leaves a stable powder or cake that keeps for years when sealed, cold and dark. The vial is reconstituted with a diluent immediately before use, which is why a research vial is labeled by mass (for example 5 mg) rather than by concentration.
Research use only
Research peptides are reagents. They are not manufactured under the pharmaceutical quality systems (cGMP) required for drugs, they are not sterile-filled as injectables, and they have no approved use in humans or animals. "Research use only" is not a formality: it defines the product, the legal basis on which it is sold, and the testing it receives. Valor Synthetics sells to purchasers who confirm they are 21 or older and are buying for in-vitro laboratory work. See the research use policy.