Yes. It can regrown based on the type of illness. Baldness is a sign of many disease. There is option of hair transplant also

Use minoxidil spray on bald areas, but hair regrowth will be as long as you use this medicine. Permanent solution is hair transplant

Definitely hair can be regrown on bald patches. Use mx 5% solution once at night before sleep. Do not use any other oil. After bathing, use Folica lotion on the bald patch once. Have Apraize 10mg once a day. Continue the following medication for 3-4 months along with maxirich vitamins

Your answer can't be answered in one sentence as well. What people are saying about doctors has nothing to do with the treatment of hairfall. There's absolutely no medications that grow hairs back to their natural state. Although there are certain medications which stops your hair loss and grow hairs as well. Also your treatment depends on what kind of alopecia you have.

Yes. Certain drugs help you grow hairs naturally (though, not fully). But, the results are seen as long as you use that drugs