do collagen peptides count as protein?

Technically, yes, collagen peptides are pure protein. However, from a strict regulatory and labeling standpoint (like FDA in the US), it’s tricky.
Because collagen completely lacks the essential amino acid tryptophan, it is classified as an incomplete protein. This means its PDCAAS (Protein Digestibility-Corrected Amino Acid Score) is effectively zero. So, while you can list the total grams of protein on the Nutrition Facts panel, you cannot count those grams toward the % Daily Value (DV) for protein. If you do, you risk non-compliance and potential lawsuits.