the gel contains platelet-rich plasma -lrb- prp -rrb- - a concentrated mix of substances in the blood that play a role in healing .
it is made up of a clear yellowish liquid , called plasma , but it also contains small , solid compounds - red cells , white cells and platelets .
the platelets are important for clotting , but they also contain hundreds of proteins called growth factors that spinning the blood leaves behind the plasma and the platelets but in higher concentration - up to ten times greater than usual .