I have lost considerable amount of hair. Is it possible to restore it? If yes, how?
Your question is too vague, so there’s not much I can offer. Sometimes medication can be beneficial, sometimes surgery would work, sometimes your hair loss could be due to other conditions such as stress, diet, allergy, infection, etc.
You’ll need an examination by a doctor to first pinpoint why you’re losing hair, then you can start to figure out how to treat it.