COLLAGEN
Collagen is one of the most abundant protein in many living organisms because it plays a connective role in biological structures. There are different types of collagen but the dominant of collagen is collagen type I . Over 90% of the collagen in human body is collagen type I which is present in skin, tendons, vasculature, lungs and heart.
Common types of collagen
Reference
Wang H. A Review of the Effects of Collagen Treatment in Clinical Studies. Polymers (Basel). 2021 Nov 9;13(22):3868. doi: 10.3390/polym13223868. PMID: 34833168; PMCID: PMC8620403
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8620403/