Hormonal Update Volume 2 Number 9

Hair Today - Gone Tomorrow

Hair loss has long been thought of as a man’s problem. And, unfortunately, by the age of 50 nearly half of all men do experience some degree of baldness. However, did you know that by the same age one out of every four women also experiences some form of baldness? It’s true.

Hair loss is never welcome, but many men expect that over their lifetime they will lose some of their hair. On the other hand, female pattern baldness is not something a woman anticipates. Women are often shocked when they start losing their hair. In our youth and beauty oriented culture, hair is such an important part of our self-image. Whether you are a man or a woman, hair loss can be a devastating experience, accompanied by feelings of worry, embarrassment and fear.

Treatment for hair loss dates back 2500 years. Hippocrates, the father of modern medicine, is believed to have poured sheep’s urine over his scalp in an attempt to prevent his hair from falling out. Thankfully treatments for hair loss have improved.

You have, on average, 100,000 hairs on your head. Seems like a lot, doesn’t it? However, when you begin losing them, each little hair takes on a whole new importance. So, what causes hair loss? More and more studies show that the root of the problem just might be hormonal. In this Hormonal Update we take a look at hair loss, what causes it, and what you can do to help prevent it.

The Physiology of Hair

Hair is composed of dead cells that grow out of a little bulbous pocket called a hair follicle. Follicles lie just under the surface of the skin. They are nourished by tiny blood vessels and oil glands, and cycle through a pattern of growth, rest, and regrowth. Once a follicle’s rest phase is concluded the old hair is shed and a new one begins to grow. 

Hairs are shed and replaced at staggered intervals, with a single strand of hair growing at a rate of about one-half inch per month, for anywhere from two to ten years. A person normally loses from 50 to 125 hairs per day. As long the growing phase keeps pace with the shedding phase, hair remains abundant. Problem hair loss occurs when hairs cease to grow back or when there is a consistent and persistent loss of more than 150 hairs per day. 

What Causes Hair Loss

It is important to note that many forms of hair loss are temporary and can be reversed. Once the underlying cause is addressed, hair growth returns to normal within a few months. In women, iron deficiency and low B-12 levels are among the most common dietary reasons for hair loss. Excessive vitamin A intake is another. In older women, not getting enough animal protein in their diet can contribute to hair loss. Animal protein contains all of the amino acids necessary for cell life, including the cells in hair follicles. 

Both physical and emotional stress can cause, or exacerbate, hair loss. Illness, surgery, rapid weight change, loss of a job, or death of a loved one can all spark its onset. Often, in stress-related hair loss there is a three-month delay between the actual stressful event and the shutdown of hair production. Continued stress management can help restore hair growth. 

Some medical conditions including lupus, anemia, diabetes, and thyroid imbalances can cause hair loss. Hair loss is known to be a side-effect of certain medications, particularly anticoagulants, mediations for gout, drugs derived from vitamin A, beta blockers, birth control pills, anti-depressants and anti-thyroid agents. If you suspect that one of your medications is causing your hair to fall out check with your pharmacist. You may then want to consult with your doctor about finding a substitution. 

During pregnancy, when hormone levels are high, many women enjoy thicker and shinier hair. After childbirth, the dramatic drop in hormone levels can, and often does, lead to hair loss. This shedding of hair may begin a few weeks after the baby is born, and last as long as ten months. Once hormone levels are balanced again, pregnancy-related hair loss resolves itself.

Androgenetic alopecia, also known as male-pattern or female-pattern baldness, is an inherited, hormone linked condition affecting about 40 million men and more than 20 million women in the U.S. The main difference between male and female pattern baldness is the severity and distribution of the hair loss. Men tend to lose hair from the hairline and over the crown of the head; women tend to lose hair over the entire scalp. This form of hair loss is generally not temporary. However, greater understanding of the link between hormones and hair loss is leading to new techniques for preventing and managing this condition. 

The Hormone Connection

Increasingly, scientific evidence suggests that hair loss and hormonal imbalance are connected. For example, evidence is mounting that hair loss is a symptom of an androgen estrogen imbalance. Elevated androgens, as well as the hair follicle’s response to the androgens, can disrupt the hair cycle and cause hair to fall out.

Androgens are a class of hormones produced by the adrenal gland in both sexes, in the ovaries in women, and the testes in men. Testosterone is an androgen. The cycle of hair growth is controlled by an enzyme called 5 alpha-reductase type 2, which converts testosterone into dihydrotestosterone (DHT). 

DHT is the active form of testosterone, present in both men and women. New studies have shown that DHT plays an important role in hair loss. It appears that over the course of a few hair cycles high DHT levels cause hairs to become finer and shorter. It also shortens the growth phase and accelerates the number of hairs entering the resting phase.

Many of the commercial hair restoration products, such as finasteride, and Propecia, block the formation of DHT. This enables hair follicles that are inactive to become active again and make new hairs.

Estrogen can also suppress the availability of androgens. This is the result of a complex feedback mechanism that results in high estrogen levels reducing testosterone production. High estrogen levels can also affect the production of sex hormone binding globulin (SHBG), by increasing it. SHBG is a protein that binds to a sex hormone and prevents it from being converted into its active form. For example, SHBG helps prevent testosterone from converting into DHT. 

However, animal studies have shown that too much estrogen can put hair in the resting phase and can prevent it from growing. Similar studies have shown that men with higher than normal levels of estrogen are more prone to hair loss. 

During the transition from perimenopause to menopause many women notice that their hair is dull, dry or thinning. This is associated with the fluctuation, decline, and consequent imbalances between estrogen, progesterone and testosterone. 

Hysterectomy or removal of the ovaries also brings about a hormonal disruption that can lead to hair loss. This is particularly noticeable among women who are not taking hormone replacement. It is becoming more evident all the time that the balance between hormones is important to hair growth. Hormonal imbalances can be corrected with hormone replacement therapy (HRT). Generally men are not candidates for estrogen replacement, however progesterone supplementation has been shown to help reduce hair loss. Initial studies indicate that progesterone may block the production of DHT.

Restoring Balance