One of the best hair tonics of which I have ever he is this very old-fashioned recipe, but it must be used sparingly, or it will leave the hair uncomfortably sticky.
To prepare, cut a fair-sized onion into slices and cover with unsweetened gin. Leave for at least a day before using, afterward do not strain. Brush the hair well each night massage a little of the mixture into the roots with the tip the fingers.
If there is any life in the scalp at all this will cure baldness and promote a fresh growth of hair.