Male pattern hair loss (androgenetic alopecia) is a medical condition characterized by progressive hair loss and thinning at the vertex, temporal regions, and frontal region of the scalp in men. A similar condition may occur in women, but generally only results in hair loss at the midline of the scalp (female pattern baldness). Both of these conditions are caused by a combination of genetic factors and elevated androgens levels in scalp tissue.
Androgenic alopecia usually affects men who have recently gone through puberty, most commonly between the ages of 18-40. Women are usually affected after menopause (age 50) and have a slightly different pattern of hair loss. The condition can be cosmetically displeasing, leading to embarrassment and loss of self-confidence and self-esteem. Interestingly, male pattern hair loss is associated with heart disease.
Androgenetic alopecia is caused by a combination of genetic factors and elevated levels of Dihydrotestosterone (DHT) in scalp tissue. It is not only passed on by the mother as many people claim – in fact, genes from both parents are important for the development of this condition.
Male and female pattern hair loss begins when testosterone is converted into DHT by the enzyme 5-alpha reductase. This enzyme is located in high quantities in scalp tissue and the prostate. In the scalp, DHT acts on hair follicles causing them to undergo a process called miniaturization. This means that the hair follicles shrink because they spend less time in the growth phase – eventually dying off completely.
Male and female pattern hair loss is also related to poor circulation in the scalp tissue. Correcting poor circulation and elevations in the level of DHT are critical to slowing, stopping, or reversing hair loss.
Hair loss is extremely common with an estimated 70% of the US population experiencing significant hair loss in their lifetime. Up to 50% of men below the age of 50 and 80% of men below the age of 80 experience significant hair. Men are also affected much earlier in life than women, with hair loss beginning in the early ’20s in many individuals.
Women traditionally experience hair loss later in life after the beginning of menopause. Up to 50% of women experience some level of hair loss after the age of 50.
In men, androgenic alopecia results in hair loss in the following areas, this pattern of hair loss is what gives this condition the name “male pattern baldness.”
- The vertex – the crown of the head
- Both temples
- Frontal region
In women, the pattern of hair loss is different, likely due to differences in the distribution of the enzymes that convert testosterone to DHT and lower levels of testosterone. “Female pattern baldness” presents with hair loss in the following areas:
- The center of the scalp – along the natural part of the hair
- The Vertex
Some women develop loss of hair due to hyperandrogenism – a condition characterized by elevated androgen levels – resulting in irregular menses, acne, and hirsutism. Hirsutism is the development of hair in areas that usually appear in men, such as the face, inner thighs, and back.
Androgenic alopecia is often suspected based on the pattern of hair loss and your age. The majority of the diagnosis is focused on ruling out other conditions that can result in hair loss. The most common of which include:
- Iron deficiency (e.g. hemoglobin, iron levels, total iron-binding capacity, ferritin),
- Thyroid disease (e.g. TSH, free T4),
- Syphilis (e.g. RPR).
If you are a woman with abnormal menstrual periods, infertility, significant acne, or facial hair – your doctor may work you up for hyperandrogenism. This condition is evaluated by checking your testosterone, dehydroepiandrosterone sulfate, and prolactin levels.
In men older than 18 years, the most common treatment for pattern hair loss includes:
- Rogaine (minoxidil 2%)
- Propecia (finasteride)
Rogaine (minoxidil) works by dilating the blood vessel in the scalp. This promotes increased blood flow to the scalp tissue, thereby encouraging hair follicle health and hair growth. It is usually applied topically to the scalp twice daily. It is available in shampoo, gel, and cream formulations.
Propecia (finasteride) is an oral medication that works by inhibiting the enzyme 5-alpha reductase. This results in less conversion of testosterone to DHT. Remember – DHT promotes hair follicle miniaturization and hair loss – therefore, finasteride prevents hair loss by reducing DHT levels. Finasteride is also used in patients with benign prostatic hyperplasia (BPH) – which is a common condition in older men characterized by an enlarged prostate and urinary symptoms.
DHT is important for sexual function – therefore, 5-alpha reductase inhibitors such as Propecia (finasteride) may produce undesirable side effects such as decreased libido, erectile dysfunction, and problems with ejaculation.
Propecia (finasteride) is not usually effective in treating hair loss in women. Most women with androgenetic alopecia benefit from topical Rogaine (minoxidil) therapy – similar to men. In women in a hyperandrogenic state, Aldactone (spironolactone) may be effective as it inhibits androgen receptors slowing the growth of hair in unwanted areas and slowing its loss on the scalp.
People who are not interested in any of the aforementioned medications may decide to use toupees, hair pieces, hair extensions, or wigs. Some individuals may benefit from hair transplantation or the insertion of hair plugs. These procedures carry the risk of infection and scarring but can be very successful when performed by a skilled surgeon.
- Varothai S, Bergfeld WF. Androgenetic alopecia: an evidence-based treatment update. Am J Clin Dermatol. 2014 Jul;15(3):217-30. – https://www.ncbi.nlm.nih.gov/pubmed/24848508
- Rathnayake D, Sinclair R. Male androgenetic alopecia. Expert Opin Pharmacother. 2010 Jun;11(8):1295-304. – https://www.ncbi.nlm.nih.gov/pubmed/20426708