It is important to distinguish between permanent, progressive baldness in men - which is described as 'male pattern baldness', and is usually hereditary and thought to be linked to levels of the male hormone, testosterone - and various forms of temporary hair loss which may occur in men, women and children, and can be due to illness, stress, poor nutrition, drugs or other causes.
Whatever claims have been made on behalf of various 'cures' for baldness, there is no evidence that anything can restore hair once it has ceased to grow, though it is just possible that treatment of the scalp to improve the health of the follicles from which the hairs grow, may be effective if applied at the very first signs of hair loss.
Of all the essential oils, the one that is particularly associated with the health of the hair and scalp is Rosemary, and regular vigorous massage of the scalp with Rosemary may help. Massage will, in any case, increase local circulation, which will bring a greater volume of oxygenated blood to the scalp and may help the hair follicles in that way. Such traditional treatments as rubbing a freshly cut onion on the scalp, or laying stinging nettles on it, are in fact based on the same principle of increasing the local circulation.
Temporary baldness can often be treated very effectively. The Latin term ALOPECIA is used to denote this kind of baldness, in order to make clear the distinction between it and male pattern baldness, and aromatherapy treatments are described under that heading.