Does low testosteron level affect muscle growth? if it does what should i do to enhance my muscle growth?

im 20 years old.. i get chronic blood transfusions.. everymonth like 2-3 pack RBC.. but other than that im completely normal.. except the fact that im skinny.. so yea i decided to go to the gym.. and i've enjoyed working out.. its just that i havnt seen any improvements in my muscle growth.. even a bit.. and my blood works show my testosteron level is way below the normal range. so yea.. any suggestions??? i mean.. stuff that i could actualy do..