How to Prevent Hair Loss

It is easier to prevent the falling out of healthy hairs than to regrow hair in follicles that are already dormant. Finasteride (marketed in the U.S. as Propecia) and minoxidil (marketed in the U.S. as Rogaine, and some places as Regaine) have shown some success in partially reversing loss. In a one-year study of finasteride, evaluation after one year showed five of 21 subjects (23.8%) had two-grade improvement in MNHS grade on a modified Norwood/Hamilton scale and 12 of 21 subjects (57.1%) had one-grade improvement; the others remained at the same grade. However such treatments are generally ineffective at treating extreme cases of hair loss.
Surgery is another method of reversing hair loss and baldness, although it may be considered an extreme measure. The surgical methods used include hair transplantation, whereby hair-producing follicles are taken from the back and sides of the head and injected into bald or thinning areas.

Looking forward, the prospective treatment of hair multiplication/hair cloning, which extracts self-replenishing follicle stem cells, multiplies them many times over in the lab, and microinjects them into the scalp, has been shown to work in mice, and is currently under development, expected by some scientists to be available to the public in 2009–2015. Subsequent versions of the treatment are expected by some scientists to be able to cause these follicle stem cells to simply signal the surrounding hair follicles to rejuvenate. See Baldness treatments
Topical application of ketoconazole, which is both an anti-fungal and a potent 5-alpha reductase inhibitor, is often used as a supplement to other approaches.

Interestingly, placebo treatments in studies often have reasonable success rates, though not as high as the products being tested, and even similar side-effects as the products. For example, in Finasteride (Propecia) studies, the percent of patients with any drug-related sexual adverse experience was 3.8% compared with 2.0% in the placebo group.

Regular aerobic exercise can help keep androgen levels (particuarly free androgen levels) naturally lower while maintaining overall health, lowering stress and increasing SHBG. It has been suggested that strict weight training may have a detrimental effect on hair in studies where aerobic exercise (only) was compared to either weight training (only) or a moderately sedentary life. However, there is at least one study that indicates a decline in free testosterone combined with an increase in strength. The possibility that the training was also aerobic cannot be ruled out.
Stress reduction can be helpful in slowing hair loss. Immunosuppressants applied to the scalp have been shown to temporarily reverse hair loss, though the possibly lethal side effects of this treatment make it untenable. Saw Palmetto (Serenoa repens) is an herbal DHT inhibitor often claimed to be cheaper and have fewer side effects than finasteride and dutasteride. Unlike other 5alpha-reductase inhibitors, Serenoa repens induces its effects without interfering with the cellular capacity to secrete PSA. Saw palmetto extract has been demonstrated to inhibit both isoforms of 5-alpha-reductase unlike finasteride which only inhibits the (predominant) type 2 isoenzyme of 5-alpha-reductase.

Polygonum Multiflorum is a traditional Chinese cure for hair loss. Whether the plant itself is useful, the general safety and quality control of herbs imported from China can be questionable.
Beta Sitosterol, which is a constituent in many seed oils, can help to treat BHP by lowering cholesterol. If used for this purpose, an extract is best. Consuming large amounts of oil to get at small quantities of beta sitosterol is likely to exacerbate male pattern baldness.

Resveratrol, from grape skins, is a lipase inhibitor. By decreasing the body's ability to absorb fat through the intestine walls, it reduces the total fat and calorie content of a person's diet.
While drastic, broad spectrum anti-androgens such as flutamide are sometimes used topically. Flutamide is potent enough to have a feminizing effect in men, including growth of the breasts.
In March 2006, Curis announced that it had received the first preclinical milestone, a $1,000,000 cash payment, in its hair growth program with Procter & Gamble Pharmaceuticals, a division of The Procter & Gamble Company. The program is focused on the potential development of a topical Hedgehog agonist for hair growth disorders, such as male pattern baldness and female hair loss.

In October 2006, UK biotechnology firm Intercytex announced they have successfully tested a method of removing hair follicles from the back of the neck, multiplying them and then reimplanting the cells into the scalp (Hair multiplication). The initial testing resulted in 70% of male patients regrowing hair. This treatment method is expected to be available to the public by 2009.

In January 2007, Italian stem-cell researchers say they've come up with a new technique for curing baldness. Pierluigi Santi of a Genoa clinic said stem cells could be used to "multiply" hair roots. He said the clinic would be ready to perform its first hair transplants on priority patients - those who have lost their hair in fires or other accidents - within a few months. After that, he said, "we'll open our doors to paying customers". Santi's approach works by splitting roots and growing new follicles.