|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%|
Glycine and proline concentration is as much as 20 times higher than other food sources of protein. 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 was demonstrated in a 1999 study; mice orally administered 14C hydrolyzed collagen digested and absorbed more than 90% within 6 hours, with measurable accumulation in cartilage and skin. A 2005 study found hydrolyzed collagen absorbed as small peptides in the blood.
A preclinical study investigated the effects of oral ingestion of hydrolyzed collagen, along with vitamin C and glucosamine, suggested that the moisture content of skin, its viscoelastic properties, and smoothness benefit.
The mechanism of action of ingested hydrolyzed collagen on skin may be the increased density of collagen fibrils and the fibroblasts' density (the fibroblasts being the main cells of the dermis, and those producing collagen). It may be that that the peptides of ingested hydrolyzed collagen have chemotactic properties on fibroblasts or an influence on growth of fibroblasts.
Joint & Bone Health
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.  
It has been claimed that hydrolyzed collagen may promote lean muscle mass through and the burning of fat rather than carbohydrates and proteins, toning and thickening skin, joint rebuilding, arterial strengthening, increased energy, organ rebuilding, alleviate osteoporosis, as well as lessening the symptoms of arthritis, high blood pressure, bladder weakness, chronic fatigue, shallow breathing, autoimmune, skin problems, and splitting nails.[unreliable medical source?]
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.
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- Helps to reduce joint pain associated with osteoarthritis (Bruyère et al. 2012; Benito-Ruiz et al. 2009; Clark et al. 2008).
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