It depends what oil you use!
Yes, there are oils that are beneficial for hair growth. Oils provide moisture to hair and scalp, moisture is very important to keep dry hair from breaking and shedding. Examples: Jojoba Oil, Coconut Oil, Castor Oil, Olive Oil, to name a few.
There are fast hair growth oils, that contain carrier oils such as jojoba, coconut, PLUS vitamins and sulfur, which is excellent for hair growth!
yes it can grow a forest of hair on your head
no
no
can you use vegtable oil to grow your hair
Olive oil. Massage olive oil in your hair.... btw, it will also make your hair grow
No
defenitly not if anything it ruins your hair
yes
you can use hair oil. do not use regular cooking oil!!
By massage with mustard oil
Yes it does
Nothing that you can put on from the outside will make your hair grow thicker. (With the possible exception of Minoxidil.)