I used minoxidil for 6 months, result were good.But I stop using it 2 years back.Now my hairs are falling.Should I use it again?

It is best to follow your doctor's advice over advice from the Internet. If you want to use minoxidil, consult with your doctor.

You should start using minoxidil again as soon as possible. More importantly you should schedule a visit with a reputable hair restoration surgeon for an examination. There could be other factors besides minoxidil use.

minoxidil is  scientifically proven to help with hair loss and prevent future loss of native hair. However if you genetic male pattern hair loss is advanced the benefits are limited. It is best to see a hair restoration specialist to get evaluated and find the best treatment option for you at this stage. 

Weight gain from minoxidil would be quite unusual.  I'm sure you could safely resume it.  However, if you are actually developing isolated bald spots I would see a dermatologist to assess other hair loss conditions.

Thank you for your question. Minoxidil is an effective treatment in helping regrow hair, but it's effectiveness also depends on the type of hair loss you have. Unfortunately, once minoxidil is stopped, hair loss may resume. Restarting minoxidil can help regrow your hair, but I highly recommend you consult with a board certified physician specializing in hair restoration to discuss your hair loss, assess for any underlying conditions that can cause hair loss, and treatment options that best suit you. Take care and good luck.