The Science of Genetic Hair Loss

The Science of Genetic Hair Loss

Genetically determined baldness in both men and women is referred to as androgenic alopecia. Also known as hereditary-pattern or male-pattern baldness, androgenic alopecia affects 80 percent of men by the age of 80. The percentage of women diagnosed with androgenic alopecia (female-pattern baldness) by age 80 is around 40 percent.

Androgenic alopecia in men is often characterized by a specific pattern of baldness where hair loss eventually resembles the shape of a horseshoe on the head. Female-pattern baldness mostly involves loss of hair on the top of the head. Women with FBP may notice a receding hairline at the temple as well.

Gene Studies and Hair Loss: What Does The Science Say?

Studies indicate that male-pattern baldness (MPB) is a highly heritable trait involving the location of specific genes (locus) on a chromosome. Chromosome Xq12 has been identified as the site of MPB gene variants. This chromosome also harbors an androgen receptor gene responsible for making androgen receptors. Androgens such as testosterone and luteinizing hormone are hormones that help produce sexual characteristics in male adolescents, such as deepening of the voice, sperm viability, and growth of body hair.

When combined with male-pattern baldness genes, testosterone loss in older men can contribute to acceleration of hair loss. While many men with androgenic alopecia may begin noticing signs of male-pattern baldness in their late 30s (when testosterone production starts decreasing), women with this same inherited condition typically do not experience consistent hair loss until after menopause.

Contrary to popular belief, men do not inherit male-pattern baldness from their mother. This myth started because scientists discovered years ago that baldness genes are passed down on XX (female) chromosomes. However, it's since been proven that male-pattern baldness involves numerous genetic variants and is, in fact, a polygenic condition. In other words, hair loss genes and their variants may be passed on both XX and XY (male) chromosomes. Moreover, some less common variants are not even located on XX or XY chromosomes but are passed on via other chromosome types.

Recent studies further indicate that male-pattern baldness may correlate with increased risks of cardiovascular disease and prostate cancer. While researchers aren't sure why such a correlation exists, they do agree that androgenic alopecia is a predominantly inherited condition exacerbated by hormonal imbalances, lifestyle choices, and aging.

Dihydrotestosterone (DHT) and Androgenic Alopecia

Enzymes in the testes convert testosterone into another hormone called dihydrotestosterone. DHT is necessary for body hair growth in men and women. The conversion of testosterone to DHT in women takes place in the ovaries.

People with genetic hair loss may also have hair follicle receptors that are overly sensitive to DHT. DHT sensitivity will significantly shorten the anagen phase of body and head hair growth. Consequently, thinner, weaker hair will eventually lead to partial baldness patterns seen in men with androgenic alopecia.

A lab test is available to evaluate the level of DHT in the bloodstream. Men with abnormal DHT levels may be at risk for slow wound healing, prostate gland enlargement/cancer, or coronary heart disease. Some research suggests this may be why there is a suspected correlation between hair loss genes and certain health problems.

Female-Pattern Baldness, Genes, and Estrogen

Similar to male-pattern baldness, female-pattern baldness (FPB) is an inherited condition that mostly affects women over 40. Nearly 75 percent of women with FPB experience noticeable hair loss within several years after menopause. Since FPB doesn't typically emerge full-blown until after menopause, doctors think reduced levels of estrogen and progesterone likely "trigger" FPB genes in women.

Recognizing Female-Pattern Baldness

Instead of the horseshoe pattern indicative of male-pattern baldness, women with FPB will lose hair from all areas of their head. In most cases of FPB, hair loss begins where a woman consistently parts her hair. Some may notice a receding hairline at their temples as well.

Experts typically categorize FPB in three different stages:

First stage: minor thinning of hair at the partline

Second stage: hair thinning at the partline worsens. Scalp is clearly visible when hair is parted. This stage also includes onset of hair recession at the temples

Third stage: hair is noticeably thin all over the head. Hairstyles that help cover thin spots or wigs may be needed to reduce the appearance of FPB

If a woman has a father, mother, grandparent or aunt with male-pattern or female-pattern baldness, it's likely they have inherited FPB genes.

Estrogen and Hair Loss

Clinical and anecdotal evidence indicate that estrogen may provide protection against hair loss. In addition to the majority of menopausal women experiencing hair loss, women of all ages who are treated with selective estrogen receptor modulators or aromatase inhibitors for breast cancer are prone to FPB.

Moreover, research shows that pregnant women have higher than normal estrogen levels and will experience prolonged anagen stages of hair growth. Estrogen levels then fall dramatically after childbirth. This causes hair follicles to simultaneously enter the telogen stage of hair growth, which leads to increased numbers of hairs falling out.

Treatment for Female-Pattern Baldness

Currently, minoxidil is the only FDA-approved drug to treat FPB. Many dermatologists recommend women with FPB apply the five percent minoxidil formula instead of the less-effective two percent formula, if possible.

Women with FPB who don't respond well to minoxidil may try an anti-androgen medication that lowers their level of testosterone. Male hormones like testosterone can promote female-pattern baldness or general hair loss in menopausal women. For reproductive-age women with early onset FPB and polycystic ovary syndrome (POS), an anti-androgen drug can help reduce excess testosterone in the bloodstream caused by POS.

Treatments for Genetic Hair Loss

Androgenic alopecia cannot be cured because it is a genetic trait. However, several over-the-counter and prescription treatments are available that may help reduce hair loss and stimulate new hair growth in some, but not all, individuals with genetic hair loss.

Minoxidil (Rogaine)

An OTC topical that must be applied twice a day to be effective,miinoxidil is recommended for men or women younger who have been diagnosed with androgenic alopecia. Originally developed to treat hypertension, minoxidil researchers later discovered that minoxidil stimulated production of an anti-inflammatory, hormone-like chemical called prostaglandin E2.

Minoxidil enhances the ability of PGE2 receptors to "express" or release prostaglandin E2, which appears to help hair follicles remain in the anagen phase longer. However, most people need to apply minoxidil every day for at least four to five months before they see results. While minoxidil may help delay or prevent future hair loss in men or women with androgenic alopecia, it generally cannot restore receding hairlines or regrow hair in completely bald spots. Discontinuing use of minoxidil usually leads to loss of new hair after two to three months \

Minoxidil should not be used by individuals:

• Who experience sudden and dramatic hair loss for unknown reasons

•	Under 18 years of age

•	Have irritated, infected or painfully inflamed scalps

•	Suffering hair loss due to misuse of hair products (dyes, bleaches, etc)

•	Have conditions that cause hair loss (thyroid disease, nutritional deficiency, alopecia areata) without discussing with an professional

Finasteride (Propecia)

A prescription-only medication for androgenic alopecia, finasteride is available as a once-a-day pill for men only. Finasteride is ineffective for women with genetic hair loss and may cause birth defects.

By blocking the formation of DHT in men, finasteride prevents hair follicle shrinkage to encourage healthy hair growth. Most men see results within six months to one year of taking one 1mg finasteride pill every day. Some men report side effects from taking this drug, such as loss of libido, premature ejaculation or erectile dysfunction. It may take several months for side effects to diminish once the drug is no longer taken.

Surgical Hair Transplantation

The last resort for treating hair loss is generally hair transplantation surgery performed by a certified dermatologist or plastic surgeon. Men with advanced male-pattern baldness who want to reduce the appearance of baldness at the top of their head might consider hair transplantation if other treatments fail to improve hair growth. However, a good candidate for hair transplant surgery must have areas of healthy hair on the side or back of their scalp. A dermatologist can then remove small patches or even individual follicles from these areas to be transplanted elsewhere on the head.

The most common hair transplant surgery performed is called "hair graft" surgery. A minimally invasive procedure done as outpatient treatment, hair grafting involves the doctor incising tiny pieces ("plugs") of hair-rich tissue from the scalp. Each hair plug usually contains around 15 hairs. Plugs are then grafted onto bald areas and allowed to heal for several months before more hair graft surgery can be completed.

Get a Prescription Hair Loss Treatment Online

Now that you’ve learned a little more about androgenic hair loss, it’s time to consider your options. One thing we’ve found over the years is that patients do better restoring their hair when they have individualized plans and professional guidance.

At Shapiro MD, we help men and women access the medications above, plus our own patented hair health formulations that can be used simply and easily to fight the look of thinning or balding hair. But now, we also offer custom prescription treatments for men and women of all hair types. These dermatologist-formulated solutions contain powerful ingredients like minoxidil and tretinoin, both trusted and used by dermatologists in private practice for decades. Now, it’s all online, plus access to your prescribing clinician by chat any time you need.

Click here to get started yourself with Shapiro MD.

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