Kelp tablets are supposed to make hair and nails grow faster and stronger.
Hair and nail tablets from Holland and Barrett
Mega Vits seem to be making my hair grow fast - they are also from Holland and Barrett
In short, you can't. Putting pregnancy and illness aside, hair pretty much grows at a maximum rate of half an inch per month no matter what you do. A little faster in the summer than in the winter.
There are no known remedies or concoctions that work.
agree with john lambert - when you're conditioning your hair, give your scalp a really good massage for a few minutes - it stimulates blood flow to the scalp area and promotes growth. i know we're all different but it works for me.