Collagen is a complex structural protein found in skin hair and nails rich in amino acids the building blocks of protein contains vitamin c to support collagen formation holland barrett hydrolysed collagen caplets 1000mg 180 caplets collagen is a complex structural protein mostly found in fibrous tissues such as tendons ligaments cartilage bone and skin holland barrett hydrolysed collagen is made up of amino acids which help compose new collagen in the body the caplets are solub