|This article relies too much on references to primary sources. (December 2013)|
||This article possibly contains original research. (December 2013)|
Hydrolyzed collagen is produced from collagen found in the bones, skin, and connective tissue of animals such as cattle, fish, horses, pigs, and rabbits. The process of hydrolysis involves breaking down the molecular bonds between individual collagen strands using combinations of heat, acids, alkalis, or enzymes. Typically, with skin-sourced collagen, hides are put in a lime slurry pit for up to 3 months, loosening collagen bonds; the hides are then washed to remove lime, and the collagen extracted in boiling water. The extracted collagen is evaporator concentrated, desiccated with drum driers, and pulverized.[unreliable source?]
Amino acid content
The amino acid content of hydrolyzed collagen is the same as collagen. Hydrolyzed collagen contains 20 amino acids, predominantly glycine, proline and hydroxyproline, which together represent around 50% of the total amino acid content.
|Other essential amino acids||16%|
|Other non-essential amino acids||12%|
Amino acid content
Hydrolyzed collagen contains 8 out of 9 essential amino-acids, including glycine and arginine—two amino-acid precursors necessary for the biosynthesis of creatine. It contains no tryptophan and is deficient in isoleucine, threonine, and methionine.
The bioavailability of hydrolyzed collagen in mice was demonstrated in a 1999 study; orally administered 14C hydrolyzed collagen was digested and more than 90% absorbed within 6 hours, with measurable accumulation in cartilage and skin. A 2005 study in humans found hydrolyzed collagen absorbed as small peptides in the blood.
Effects on skin
Ingestion of hydrolyzed collagen may affect the skin by increasing the density of collagen fibrils and fibroblasts, thereby stimulating collagen production. It has been suggested, based on mouse and in vitro studies, that hydrolyzed collagen peptides have chemotactic properties on fibroblasts or an influence on growth of fibroblasts.
Joint and bone effects
Some clinical studies report that the oral ingestion of hydrolyzed collagen decreases joint pain, those with the most severe symptoms showing the most benefit. Beneficial action is likely due to hydrolyzed collagen accumulation in the cartilage  and stimulated production of collagen by the chondrocytes, the cells of cartilage. Several studies have shown that a daily intake of hydrolyzed collagen increases bone mass density. It seems that hydrolyzed collagen peptides stimulated differentiation and osteoblasts activity- the cells that build bone- over that of osteoclasts (cells that destroy bone).
However, other clinical trials have yielded mixed results. In 2011, the European Food Safety Authority Panel on Dietetic Products, Nutrition and Allergies concluded that "a cause and effect relationship has not been established between the consumption of collagen hydrolysate and maintenance of joints". Four other studies reported benefit with no side effects; however, the studies were not extensive, and all recommended further controlled study. One study found that oral collagen only improved symptoms in a minority of patients and reported nausea as a side effect. Another study reported no improvement in disease activity in patients with rheumatoid arthritis. Another study found that collagen treatment may actually cause an exacerbation of rheumatoid arthritis symptoms.  
Hydrolyzed collagen, like gelatin, is made from animal by-products, including skin, bones, and connective tissue. It is possible that consumption of hydrolyzed collagen risks contraction of Transmissible spongiform encephalopathy.
The U.S. Food and Drug Administration (FDA), with support from the TSE (Transmissible spongiform encephalopathy) Advisory Committee, has since 1997 been monitoring the potential risk of transmitting animal diseases, especially bovine spongiform encephalopathy (BSE). The FDA study concluded: "...steps such as heat, alkaline treatment, and filtration could be effective in reducing the level of contaminating TSE agents; however, scientific evidence is insufficient at this time to demonstrate that these treatments would effectively remove the BSE infectious agent if present in the source material."
In cosmetics, hydrolyzed collagen may be found in topical creams, acting as a product texture conditioner, and moisturizer.
- Bensaid, A.; Tomé, D.; L’Heureux-Bourdon, D.; Even, P.; Gietzen, D.; Morens, C.; Gaudichon, C.; Larue-Achagiotis, C.; Fromentin, G. (2003). "A high-protein diet enhances satiety without conditioned taste aversion in the rat". Physiology and behavior 78 (2): 311–320. doi:10.1016/S0031-9384(02)00977-0. PMID 12576130.
- Fricke, O.; Baecker, N.; Heer, M.; Tutlewski, B.; Schoenau, E. (2008). "The effect of L-arginine administration on muscle force and power in postmenopausal women". Clinical physiology and functional imaging 28 (5): 307–311. doi:10.1111/j.1475-097X.2008.00809.x. PMID 18510549.
- Oesser, S.; Adam, M.; Babel, W.; Seifert, J. (1999). "Oral administration of 14C labelled gelatine hydrolysate leads to an accumulation of radioactivity in cartilage of mice (C57/BL)". Journal of nutrition 129 (10): 1891–1895. PMID 10498764.
- Iwai, K.; Hasegawa, T.; Taguchi, Y.; Morimatsu, F.; Sato, K.; Nakamura, Y.; Higashi, A.; Kido, Y.; Nakabo, Y.; Ohtsuki, K. (2005). "Identification of food-derived collagen peptides in human blood after oral ingestion of gelatine hydrolysates". Journal of Agricultural and Food Chemistry 53 (16): 6531–6536. doi:10.1021/jf050206p. PMID 16076145.
- Matsuda, N.; Koyama, Y., Hosaka, Y., Ueda, H., Watanabe, T., Araya, T., Irie, S. and Takehana K. (2006). "Effects of ingestion of collagen peptide on collagen fibrils and glycosaminoglycans in the dermis". Journal of nutrition vitaminology 52 (3): 211–215. doi:10.3177/jnsv.52.211.
- Postlethwaite, A.E.; Seyer, J.M.; Kang, A.H. (1978). "Chemotactic attraction of human fibroblasts to type I, II, and III collagens and collagen-derived peptides". Proc Natl Acad Sci USA 75 (2): 871–875. doi:10.1073/pnas.75.2.871. PMC 411359. PMID 204938.
- Shigemura, Y.; K Iwai; F Morimatsu; T Iwamoto; T Mori; C Oda; T Taira; EY Park; Y Nakamura; K Sato (2009). "Effect of prolyl-hydroxyproline (Pro-Hyp), a food-derived collagen peptide in human blood, on growth of fibroblasts from mouse skin". Journal of Agricultural and Food Chemistry 57 (2): 444–449. doi:10.1021/jf802785h. PMID 19128041.
- Moskowitz, R. (2000). "Role of collagen hydrolysate in bone and joint disease". Seminars in arthritis and rheumatism 30 (2): 87–99. doi:10.1053/sarh.2000.9622. PMID 11071580.
- Ruiz-Benito, P.; Camacho-Zambrano, M.M.; Carrillo-Arcentales, J.N.; Mestanza-Peralta, M.A.; Vallejo-Flores, C.A.; Vargas-Lopez, S.V.; Villacis-Tamayo, R.A.; Zurita-Gavilanes, L.A. (2009). "A randomized controlled trial on the efficacy and safety of a food ingredient, collagen hydrolysate, for improving joint comfort". International journal of food science and nutrition 12: 1–15. doi:10.1080/09637480802498820.
- Oesser, S.; Seifert, J. (2003). "Stimulation of type II collagen biosynthesis and secretion in bovine chondrocytes cultured with degraded collagen". Cell tissue research 311 (3): 393–399. doi:10.1007/s00441-003-0702-8. PMID 12658447.
- Nomura, Y.; Oohashi, K.; Watanabe, M. and Kasugai (2005). "Increase in bone mineral density through oral administration of shark gelatine to ovariectomized rats". S Nutrition 21 (11-12): 1120–1126. doi:10.1016/j.nut.2005.03.007. PMID 16308135.
- Wu, J.; Fujioka, M.; Sugimoto, K.; Mu, G.; Ishimi, Y (2004). "Increase of effectiveness of oral administration of collagen peptide on bone metabolism in growing and mature rats". Bone and mineral metabolism 22 (6): 547–553. doi:10.1007/s00774-004-0522-2. PMID 15490264.
- European Food Safety Authority - EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on the substantiation of a health claim related to collagen hydrolysate and maintenance of joints pursuant to Article 13(5) of Regulation (EC) No 1924/20061. EFSA Journal 2011;9(7):2291.
- Barnett ML, Kremer JM, St Clair EW, Clegg DO, Furst D, Weisman M, Fletcher MJ, Chasan-Taber S, Finger E, Morales A, Le CH, Trentham DE: Treatment of rheumatoid arthritis with oral type II collagen. Results of a multicenter, double-blind, placebo-controlled trial. Arthritis Rheum 1998 Feb;41(2):290-7.
- Ausar SF, Beltramo DM, Castagna LF, Quintana S, Silvera E, Kalayan G, Revigliono M, Landa CA, Bianco ID: Treatment of rheumatoid arthritis by oral administration of bovine tracheal type II collagen. Rheumatol Int. 2001 May;20(4):138-44.
- Trentham DE, Dynesius-Trentham RA, Orav EJ, Combitchi D, Lorenzo C, Sewell KL, Hafler DA, Weiner HL: Effects of oral administration of type II collagen on rheumatoid arthritis. Science 1993 Sep 24;261(5129):1727-30.
- Bagchi D, Misner B, Bagchi M, Kothari SC, Downs BW, Fafard RD, Preuss HG: Effects of orally administered undenatured type II collagen against arthritic inflammatory disease: a mechanistic exploration. Int J Clin Pharmacol Res. 2002;22(3-4):101-10.
- Sieper J, Kary S, Sorensen H, Alten R, Eggens U, Huge W, Hiepe F, Kuhne A, Listing J, Ulbrich N, Braun J, Zink A, Mitchison NA: Oral type II collagen treatment in early rheumatoid arthritis. A double-blind, placebo-controlled, randomized trial. Arthritis Rheum. 1996 Jan;39(1):41-51.
- McKown KM, Carbone LD, Kaplan SB, Aelion JA, Lohr KM, Cremer MA, Bustillo J, Gonzalez M, Kaeley G, Steere EL, Somes GW, Myers LK, Seyer JM, Kang AH, Postlethwaite AE: Lack of efficacy of oral bovine type II collagen added to existing therapy in rheumatoid arthritis. Arthritis Rheum. 1999 Jun;42(6):1304-8
- Cazzola M, Antivalle M, Sarzi-Puttini P, Dell’Acqua D, Panni B, Caruso I: Oral type II collagen in the treatment of rheumatoid arthritis. A six-month double blind placebo-controlled study. Clin Exp Rheumatol. 2000 Sep-Oct; 18(5):571-7.
- Helps to reduce joint pain associated with osteoarthritis (Bruyère et al. 2012; Benito-Ruiz et al. 2009; Clark et al. 2008).
- U.S. Food and Drug Administration. "The Sourcing and Processing of Gelatin to Reduce the Potential Risk Posed by Bovine Spongiform Encephalopathy (BSE) in FDA-Regulated Products for Human Use".