Collagen
What is it?
Collagen is used to form connective tissues, including skin, bone, cartilage, tendons, ligaments, hair, and nails, and is built from peptide chains consisting of glycine and a combination of other amino acids, most often proline and hydroxyproline. (35) The five most common types of collagen include Type I (dermis, tendon, ligaments, bone), Type II (cartilage, vitreous body, nucleus pulposus), Type III (skin, vessel wall, reticular fibers), Type IV (basal lamina, epithelial layer of basement membranes), Type V (lung, cornea, hair, fetal membranes, bones). (34) Type X collagen may have a role in bone health, (33) particularly through the mineralization of cartilage in the subchondral bone. (1) Supplements may contain collagen derived from bovine, porcine, marine, fish, and other sources, (35) such as eggshell membranes. (28)
Not be confused with: Colostrum
Download ingredient reviewMain uses
Formulations
Dosing & administration
Adverse effects
Collagen supplements are generally considered as safe without the common occurrence of adverse effects. (7)(19) Feelings of fullness or disagreeable taste have been reported in rare cases. (22) To avoid the possibility of allergic reactions, consideration of the source of collagen may be required. (29)
Pharmacokinetics
Absorption
- Collagen hydrolysates are degraded in the digestive tract and are mostly absorbed as amino acids, dipeptides, and tripeptides. (40)
- Absorbed via the brush-border membrane using the H+-coupled peptide transporter, PEPT1. (5)
- Ingestion in tripeptide form may improve absorption efficiency in humans. (40)
Distribution
- The collagen hydrolysate peptide, PRO-HYP, is distributed to the skin, cartilage, and bone marrow in its intact form, with its highest concentration in gastric and intestinal walls. (12)
Metabolism
- The liver metabolizes collagen peptides, though many HYP-containing peptides (some of which can be larger than tripeptides) can pass through the liver to enter systemic circulation. (25)