Calling both materials peptides hides a category error. A discrete research or cosmetic sequence is a single principal chemical species. A collagen hydrolysate is a polydisperse mixture produced by enzymatic or chemical cleavage of a larger protein.
What collagen peptide usually means in raw-material trade
Hydrolysates are specified by source, average molecular-weight range, and degree of hydrolysis. Mass spectra, when provided, show envelopes, not one monoisotopic mass. HPLC traces are correspondingly complex. That can be a valid ingredient class. It is not a single-sequence peptide.
What a defined sequence requires
A defined oligopeptide should have one sequence and stated termini; a principal HPLC peak with a stated method; a mass consistent with the calculated monoisotopic or average mass; and a lot identifier that ties those data to the container.
Why quotes get mixed
A hydrolysate is often cheaper per gram. That is expected: you are not buying a single synthetic species. Converting the two into a cost-per-milligram comparison without stating the object being bought is not a specification review.
Practical comparison rule
If the identity line is a sequence, demand sequence-level documents. If the identity line is a hydrolysate, demand source and molecular-weight information. Do not accept a sequence COA as cover for a hydrolysate, or the reverse.
Research-use and professional buyer information only.