Most Helpful Guy
eat well. that is the only answer I know that is safe. There are some poisons that will make your hair grow but they are quite toxic. People use them on show dogs to get a longer coat and long ago women used them to get longer glossier hair (but it shortened their lives, I assume). I will refrain from listing them here.
I would stick to increasing your dietary intake of fish, oils, protein from any source, spinach, guava, make sure you have iron to prevent hair breakage, cinnamon, eggs, oysters for Zinc. See the following link: www.webmd.com/.../slideshow-foods-healthy-hair2