I haven't seen whitening of my skin from glutathione, can I still expect to see some whitening even after my treatment is over?

I have been receiving Glutathione injections for the past month. I have received a double dose of 600 mg twice a week. My complexion is medium to fair. I know that i have received the recommended quantity of glutathione for skin whitening. However I have seen no visible whitening of my skin, can I still expect to see some whitening even after my treatment of 20 vials is over?