Hydrolyzed collagen is a highly digestible protein, and an oral ingestion has been reported as having beneficial effects on joint & bone health, on skin health and for weight management and sports performance.
The bioavailability of hydrolyzed collagen has been demonstrated by many studies. In a study of 1999, scientists demonstrated on mice that more than 90% of orally administered 14C labelled hydrolyzed collagen is digested and absorbed in 6 hours after ingestion. An important part is accumulated in cartilage and skin.In another study of 2005, scientists showed that the hydrolyzed collagen is absorbed in small peptides in the blood.
One preclinical study investigated the effects of oral ingestion of hydrolyzed collagen, along with vitamin C and glucosamine, on the skin properties of women tending to have dry and rough skin. This study suggested that, with the ingestion of 5g per day during 6 weeks, the moisture content of the skin, its viscoelastic properties and its smoothness improved.
Regarding the mechanism of action of hydrolyzed collagen on skin, it seems that orally ingested hydrolyzed collagen increases the density of collagen fibrils and the fibroblasts density (the fibroblasts being the main cells of the dermis, and the ones which produce collagen). The explanation of this action may be 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 10g of hydrolyzed collagen by day decreases the joint pain, and that patients having the most severe symptoms benefited more.
Other clinical trials have yielded mixed results. Four studies reported positive effects with no side effects. However, the studies were not extensive and all recommended the need for further controlled studies.
Another 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. Yet another study found that collagen treatment may actually cause an exacerbation of rheumatoid arthritis symptoms.
Any beneficial action is probably due to the fact that hydrolyzed collagen is accumulated in cartilage and stimulates the production of collagen by the chondrocytes, the cells of cartilage.
On bone health, several studies have shown that a daily intake of 10g per day of hydrolyzed collagen for 4 to 24 weeks increases bone mass density. It seems that hydrolyzed collagen peptides stimulated the differentiation and the activity of osteoblasts, the cells that build the bone, instead of osteoclasts, those that destroy it.
Hydrolyzed collagen is a good protein to use in blends with others for a weight management diet. It contains 8 out of 9 essential amino-acids, and proteins are recognized as being the most satiating macronutrient. Hydrolyzed collagen is also a good ingredient for a sportive diet. It is important for athletes to restore their protein content after an exercise, and the consumption of hydrolyzed collagen that contains more than 97% of protein can help it. Hydrolyzed collagen also contains some glycine and arginine, two of the three amino-acids of the creatine, a molecule which present in the body and having an important play during the exercise, providing energy to the body. Finally, hydrolyzed collagen contains some arginine, which has been shown to be efficient to improve the athletic performance.