Collagen refers to a family of proteins that are the primary structural component of connective tissues, such as skin and cartilage, according to Yale University. 

The substance makes up about a third of all the protein in the human body, more than any other type of protein in the body by mass. There are 28 different types of collagen, each type categorized based on its amino acid composition. About 90% of the collagen in the body is type 1, which is found in the skin, tendons, internal organs and organic parts of bone, according to Healthline. The vast majority of the remaining collagen in the body is made up of the following types:

Type 2: Found in the cartilage.

Type 3: Found in the bone marrow and lymphoid tissues.

Type 4: Found in the basement membrane (thin sheets of collagen that surround most types of tissues).

Type 5: Found in the hair and the surfaces of cells.

3840 5099
2625 3699
3499 4299
4129 5199
2479 3299
1799 2099
2699 2999
3099 3399
1599 1899
6599 6899
3599 3899
5499 5799
2199 2499
3199 3499
4799 4999
3299 3599
3499 3699
3599 3999
5999 6299
9099 9399
4799 5099
4975 5999
4975 5999
4975 5999
2274 2899