Is there any medicine I can take to increase milk supply?

I’ve heard of friends taking Domperidone medicine to help with supply issues. However, the effectiveness seemed to varies for everyone. Some found it effective while others had no success with it. One of the successful ones took four times a day, drank plenty of water and was also pumping more. Another friend took Fenugreek (from GNC) instead, 6 pills a day and felt that it helped. Some side effects from Domperidone may include headache, abdominal cramps and dry mouth. My friend had slight headache but unsure whether it was due to the medication. You can purchase it from pharmacies from Unity or Guardian or go through your doctor.