what is collagen peptides made of?

As a brand owner, the most important thing I have to explain to my customers about what collagen is made of is what it is not made of: plants.
There is no such thing as vegan collagen. Since collagen is exclusively an animal protein, true collagen peptides are always 100% animal-derived. When we get customers looking for vegan alternatives, we have to pivot and sell them “collagen builders” (which are made of plant-based vitamins and amino acids), but the peptides themselves are strictly sourced from animals.

I think it’s really important to highlight the sustainability aspect here. When consumers ask what it’s made of, some get squeamish, but they shouldn’t.
Collagen peptide production is actually a fantastic example of upcycling. The raw materials (hides, bones, and scales) are by-products of the meat and fishing industries. Instead of these nutrient-dense parts going to waste, specialized facilities extract the protein to create high-value health supplements. If you are a brand owner, this is a great sustainability story to tell your customers.

Structurally, collagen peptides are made entirely of amino acids—predominantly glycine, proline, and hydroxyproline. But in terms of raw materials, they are extracted from the connective tissues of animals.
The vast majority of the commercial bulk market is made from bovine hide and bones (cow), which yields an excellent mix of Type I and Type III collagen. The second most popular source is marine scales and skins (fish), which is predominantly Type I. You can also find it made from porcine (pig) skin and poultry (chicken) cartilage, depending on the specific application.