There are various remedies postulated for prevention of hair fall but none seems to be promising. In case of hairfall secondary to dandruff, by controlling it hairfall can be decreased. But there are no good treatment for hair fall.
Essential oils have been shown (in at least one reputable published scientific study that I am aware of, to be effective in the treatment of alopecia). ie
Randomized trial of aromatherapy. Successful treatment for alopecia areata.
Hay IC1, Jamieson M, Ormerod AD.
I personally think they can help in a number of ways:
1. Massage reduces stress, essential oils like lavender also have some sedative properties and can reduce stress
2. Many essential oils are anti-fungal, anti-bacterial and anti-viral (sometimes alopecia can be caused by fungal, bacterial or virual infections.
3. The act of massaging gently induces circulation
4. The carrier oils used to dilute the essential oils to safe levels of use themselves have healing / soothing properties (eg jojoba, olive oil), and can help if the hair loss is caused by dermatitis/allergies etc
I would be very interested in any other studies linking aromatherapy, essential oils etc.. to treatment of alopecia.
I would never touch finasteride for the risks of permanent sexual/cognitive/memory side effects. Platelet Rich Proteins harvested from patients own blood is the most effective, all natural method.