I have looked at hgh from china.
one type is called somatotropin
cas 9002-61-3 and the other somatropin cas no 12629-01-5

Somatropin is what I have heard of and is probably what is common.
somatropin is recombinant hgh. rhGH
What does it mean that it is
recombinant.
What is the difference between these substances?