Other studies have suggested that a hydrolyzed collagen enriched diet can improve bone collagen metabolism, reduce pain in patients with osteoarthritis of knee or hip when the blood concentration of hydroxyproline increases, and also prevent osteoporosis, determined the high bioavailability of collagen where the distribution of labelled amino acids in skin was confirmed, and 58% of the peak value of the labelled amino acids remained 192 h after oral administration in mice.