well your receptors don't get 'used up' when you shoot some test, the body absorbs it in the bloodstream and takes it to all cells which have the appropriate receptor (androgen receptor, AR) The test floats through the lipid bilayer of the cell and binds to the AR. The AR takes it into the nucleus, binds to the specific genes, makes mrna, mrna makes a protein. Then your receptor goes back into the cytosol and waits for another test molecule. In short, they are either bound, or free. But they are never 'used'

It's a common misconception in BBing that your receptors get worn out or other such rubbish.