Trimatropin is Human Growth Hormone. The long medical name for Trimatropin is Somatropin [rDNA origin for injection]. Somatropin is the medical name for Human Growth Hormone. rDNA origin means it is synthetically produced in a lab using recombinant DNA technology, which produces a substance which is idential to that of what a healthy human body produces. A precise chain of 191 amino acids in a single chain polypeptide hormone.