do collagen peptides count as protein?

It’s helpful to explain this to consumers in terms of “building blocks.”
Does it count towards your daily macronutrient and calorie intake? Absolutely (it yields about 4 kcal per gram). However, because it’s low in BCAAs (branched-chain amino acids) like leucine, it won’t stimulate muscle protein synthesis (MPS) the way traditional proteins do. We buy and use collagen peptides specifically for the connective tissues—hair, skin, nails, tendons, and cartilage—thanks to its high concentration of glycine, proline, and hydroxyproline.

Ethan hit the nail on the head. Biochemically, it’s protein, but functionally, it serves a different purpose.
When I formulate a meal replacement or a sports powder, I never use collagen as the primary protein source due to its biased amino acid profile. Instead, I use it synergistically. We often blend high-quality collagen peptides with a complete protein like whey isolate or a pea/rice protein blend. This way, the client can make a “High Protein” claim on the front of the packaging while also offering the functional joint and skin benefits of collagen.

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.