Hair originates in the dermis, the skin layer just below the surface layer (epidermis).  For more information on hair.

Baldness (alopecia), or severe hair loss, is much more common in men than in women. It can result from genetic factors, aging, local skin conditions, and diseases that affect the body generally (systemic diseases). Some medications, such as those used to treat cancer, also cause hair loss.

Male-pattern baldness is the most common type of hair loss affecting men. It's rare in women and children because it depends on the presence of the male hormones (androgens), and levels of these hormones are high in males after puberty. Baldness runs in families. The hair loss usually begins on the sides, near the front, or on the top of the head toward the back. The hair loss can begin at any age, even in the middle teen years. Some people lose only some hair and develop a bald spot in the back or a receding hairline; others, especially people whose hair loss begins at a young age, may go completely bald.

Female-pattern baldness is less common than male-pattern baldness. Usually, this condition causes the hair to thin in the front, on the sides, or on the crown. It rarely progresses to total hair loss.

Most types of baldness have no cure. A person with male-pattern or female-pattern baldness may undergo hair transplantation, in which hair follicles are removed from one part of the body and transplanted. Some medications, such as topical minoxidil, may promote hair growth in a small percentage of people. The oral drug finasteride may also promote hair growth. Finsateride is available as Propecia 1 mg, or as Proscar 5 mg (used for enlarged prostate). It is cheaper to buy Proscar 5 mg and bite off about a fifth a day instead of buying Propecia since Proscar is only slightly more expensive than Propecia but it has 5 times as much finasteride.
   Minoxidil may also be helpful at 2% for women and 5% for men, used topically.

Natural Therapies that may be helpful for healthy hair growth
A molecule produced in the intestine when soy is digested stops a hormone which can fuel prostate growth or cause baldness. Writing in the journal Biology of Reproduction, they said the finding could explain why Japanese men, who eat more soy, rarely have prostate cancer. They said the molecule could be used as a treatment for cancer and baldness. The team found that the molecule, equol, "handcuffs" the male hormone DHT - a by-product of testosterone. The researchers say this could be particularly important for men who have been diagnosed with either an enlarged prostate (benign prostatic hyperplasia), or cancer of the prostate. DHT has also been implicated in research into the causes of male pattern baldness.

Shaving and hair growth
Q. Does shaving make hair grow back faster or thicker?
   A. Shaving has no effect on the thickness or rate of hair regrowth. But stubble lacks the finer taper of unshaven hair, giving the impression of coarseness.

Hair loss in Japanese women
Characteristic features of Japanese women's hair with aging and with progressing hair loss.
J Dermatol Sci. 2006 Dec 9; Shiseido Research Center, 2-2-1 Hayabuchi, Tsuzuki, Yokohama 224-8558, Kanagawa, Japan.
There have been few studies of the features of hair with aging and hair loss in Japanese women. Features of Japanese women's hair with aging and with progressing hair loss were investigated. Japanese women with hair loss or with no or less hair loss), aged 14-68 years, were studied. Severity of hair loss was rated by visual comparison with six standard photographs. Hair density, hair growth rate, and hair diameter were analyzed by phototrichogram. Hair loss in Japanese women is commonly characterized by a diffuse central pattern occurring after approximately 40 years of age. Hair density declines with age after the 40s. The reduction resulted from an increase in the number of one-haired follicular units and a reduction of three- and more-haired follicular units. Both the ratio and the growth rate of anagen hair also declined with age after the 40s. Mean hair diameter and the ratio of thick hairs increased with age from about 10 to 40 years, and decreased with progressing hair loss. There were few vellus-like hairs in women with hair loss, in comparison with male-pattern baldness. In Japanese middle-aged women, hair density declined with age without the appearance of hair loss. Hair loss appeared after approximately 40 years of age. The major causes might be reduction of hair density and the ratio of thick hairs, but not an increase of vellus-like hairs.

Rogaine foam better than Rogaine solution for hair growth
Rogaine in the form of foam is an effective treatment for hair loss in men and may be safer and easier to apply than the original liquid formulation. The foam causes less itching. Rogaine foam does not have propylene glycol, an chemical that commonly causes irritation and occasionally causes an allergic contact dermatitis. Rogaine is made by Pfizer Inc. Journal of the American Academy of Dermatology, November 2007.

Emails regarding hair loss
Q. I am 38 and searched the internet for info on herbal remedies to prevent hair loss. I found anecdotal references on benefits of saw palmetto, zinc, and vitamin B6 p-5-p (pyrodoxal, not pyrodoxine). All three were indicated to fight the effects of DHT's reaction with 5-alpha reductase which can have a harmful effect on hair follicles and cause hair loss. Have you heard anything more "official" on these three supplements for stopping hair loss?
   A. As far as we know, there are, as of now, no proven herbal or nutritional therapies for androgenetic hair loss. Some over the counter hormones, such as DHEA, androstendione, and pregnenolone may cause hair loss in some individuals. I am hoping that future research will indicate that certain herbs or supplements are helpful (one possibility is equol (see above), but in the meantime we do know that pharmaceutical medicines such as finasteride pills do help, but with slight side effects of potential lower sex drive. 

Q. I have just started taking 25mg of dhea prescribed by my physican after a series of blood tests. The side effect of hair loss is a concern for me as I have already got thinning hair and I'm a woman. How long will it take for me to notice this DHEA hair loss side effect and does it happen in everyone taking this amount.
   A. The hair loss side effects from DHEA can come within a few weeks and it occurs in most people but not everyone.

Q. I am working on an article for a health magazine about hair loss and how men can keep their hair and scalp healthy before they start to go bald. I’d love to find out what guys can do now to prevent hair loss later in life. So any tips you might have, from nutrition to hair care, I’d love to hear them! We're looking for things that aren't commonly known. I know there are a slew of nutrients and dietary recommendations floating out here online, but what do you recommend? What are the most important and why? How do they help keep hair healthy? What about soy? I have heard it can counteract DHT.
   A. Hair loss in men is mostly due to genetics. We all know people who eat a terrible diet with tons of fast foods and soft drinks, yet they have a full head of hair while others watch their meal selection carefully and choose healthy foods on a regular basis but still can's stop their hair loss. Although genetics has most of the influence, it is possible that a low inflammatory diet over the long run could be of benefit. This low inflammatory diet would have a high intake of fish and fish oils, a high intake of all sorts of vegetables and whole grains, and a low intake of sugar and simple carbohydrates.

Q. Is it ok, to take saw palmetto if you are breast feeding? My son is three months old and my hair is really starting to fall out and I am trying to find something that will stop it.
   A. We have not seen any studies regarding saw palmetto use and breastfeeding. It is probably safe but we can't say for certain. We don't think saw palmetto has much of an effect by itself on hair growth.

Q. After viewing info, I found that you do not have a product to restore hair or prevent hair loss. Is there a list of DHT
blockers available that are effective against hair loss, or are any products or combination of products effective in this area?
   A. We have not found a proven hair growth product and until we do, we don't feel comfortable having consumers waste their money. But, we are constantly searching for an effective natural hair growth product.

Q. I was on a weight loss program called Transformations about a year ago. It incorporates a low-calorie diet along with injections of Human Chorionic Gonadotropin hormone (HCG). I did very well on the program and lost 27 pounds. Around that same time I discontinued using Estrogen patches (Vivelle). I had a complete hysterectomy 10 years ago, ovaries removed. I have noticed over the past year that my hair seems to be thinning. I have gained the weight back and want to go on the weight loss program again, but I'm concerned whether the HCG could have had anything to do with my hair thinning. My dermatologist says it was stopping the estrogen because estrogen helps to protect hair. I stopped the estrogen because strokes run in my family and I had been on the patches for 10 years. I do have hot flashes and it can be 20 degrees outside and I'm always hot. I would consider going back on the estrogen but if for some reason I stopped it again...would I lose hair again? Do you think it was the estrogen or HCG that caused the hair loss?

Q. I'm a male without hair on my body. I serviced 6 years in the military & I have been married 5 times all ending in divorce. Maybe the women I married think maybe they are in bed with an something else. I cannot grow a beard. Watch goes here?
   A. We are not aware of any natural treatments that grow body hair.

Q. I'm a female and my hair is breaking and scalp dry, can u recommend hair vitamins for strength and growth?
   A. We will update this web page on hair and vitamins as we find out more research.

Q. I'm currently taking Propecia for hair loss and want to stop as I think there is an impact on libido and erectile function. I have tried Passion Rx and found it effective but am concerned about increasing testosterone and therefore DHT. Is there reason to think that Passion Rx would increase the rate of hair loss?
   A. We have no reason to believe Passion Rx has any significant influence on hair loss or hair growth. Plus, for long term use, most people only need to take Passion Rx 2 days a week or so.

Q. I am so glad I found your website. I love how you back up your claims with evidence! How refreshing. I am a 31 year old female who is experiencing sudden dramatic hair thinning. There is no visible baldness, just excess shedding and no visible hair growth. This problem had a sudden onset about 10 months ago. My hair normally grows about six inches in a year but there has been no visible growth for the past 10 months. There are several possible causes: I contracted histoplasmosis a year or so ago. I am on a six month course of prescription Sporanox (hair loss is not an official side effect, however, there are numerous posting on the internet of people stating that their hair began to fall after taking this drug). Finally, I was recently diagnosed with iron deficiency anemia. My question is whether there is a hair growth aid to stop hair loss (or promote hair growth) that is not a result of hormonal problems? I have been taking prescription iron tablets for a couple months but my hair is still shedding intensely. I realize that it may stop shedding after I stop the Sporanox, but I would rather not wait if there is something I can do now, especially if the hair loss is not reversible. There is a lot of "information" out there regarding "hair growth formulas", but I don't trust the validity of their claims. Any evidenced based information you can provide would be greatly appreciated.
   A. Sporanox can cause hair loss. Sporanox has other has side effects such as headache, dizziness, feeling sick, gastrointestinal symptoms, erectile dysfunction, muscle weakness. Unfortunately we are not aware of any natural hair growth formulas that work. Fo-Ti has been mentioned, and so has the combination of saw palmetto and beta sitosterol, but we have not seen good proof yet.

Q. Do you know of any products pertaining to prevention of female hair loss.
   A. We are not aware of any natural herbal products that prevent or treat female hair loss.

Q. I'm from Malaysia. Lets say somebody is losing hair, lets assume the DHT has destroyed the hair follicle, is it possible for the hair to regrow at any chance. I'm experiencing hair loss my hair is becoming thinner and its falling. I'm just afraid that it will
never grow back no matter what i do. I'm using anti-DHT shampoo for a couple of days. I just would like to know from you if my hair will regrow ever again even if the hair follicle is destroyed by the DHT.
   A. It is possible that finasteride can regrow the hair but we are not aware of natural herbs for hair growth that work effectively.

Q. Is there any natural herb or treatment that can stop hair loss and regrow hair other than minoxidil and propecia?
   A. At this time we are not aware of any effective natural hair loss remedies.