Testosterone, DHT and hair loss. Here’s what to know.

Male and female hair loss patterns have multiple possible causes. Genes are involved — probably several genes — but hormones play a role, too. And while the exact mechanism is still under study, the hormonal causes of hair loss are similar between the sexes.

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Hormones and male hair loss

Increased production of dihydrotestosterone (DHT), the strongest of the hormones that develop male sexual characteristics during puberty, is associated with gradual balding in males.

This correlation can be confusing. During puberty, when enough DHT is synthesized from its fellow androgen testosterone, it leads to the growth of both body and facial hair and the prostate. Yet it has the inverse effect on scalp hair growth in adult males: Those experiencing pattern hair loss show higher levels of DHT.

One theory is that as the lower layer of skin gets thinner with age, hair follicles experience greater pressure. At the same time, increased DHT levels speed up the growing phase of hair, and follicles begin to shrink with each growth cycle. This hair miniaturization prevents follicles from reaching their strongest state and puts more of them in a resting phase, leading to hair loss.

Another theory suggests it’s the sensitivity of hair follicles to androgens that causes male pattern balding. That’s because areas of the scalp more prone to losing hair have more androgen receptors. The negative effect of DHT on scalp hair growth still plays a significant role, though, according to the theory.

Because enzymes convert testosterone into DHT, lower testosterone levels mean lower DHT levels as well. Thus, hair loss would not be an expected symptom of low T per the elevated-DHT theory, but the connection isn’t ruled out by the androgen-sensitivity theory.

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Hormones and female hair loss

The role of androgens in female pattern hair loss is less clear. An elevated level of precursor hormones that turn into testosterone and DHT has been associated with the condition. Still, only about 25% of females with increased androgen levels may experience pattern hair loss.

Enzymes responsible for converting testosterone into a form of estrogen — the hormone driving female sexual characteristics — also play a role in how female pattern hair loss appears. 

These hormones are more concentrated on the front of the scalp. And by subverting the eventual production of DHT, female pattern hair loss doesn’t tend to present at the hairline or around the temples as it does in males.

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So, is hair loss a symptom of low T or not?

Despite disparities in defining low testosterone, studies have found it’s not especially common. Testosterone invariably declines with age, and perhaps around 8% of males over age 50 have concentrations of total testosterone in the lowest percentile range. Clinicians don’t have a standardized measure of “normal” testosterone levels in females. 

But pattern hair loss occurs widely, affecting around half of males over 50 and up to 30 million females in the United States. That’s why, particularly for males, other indicators are used more often to diagnose low T. Here are some to note:

Symptoms of low T for both sexes: 

• A lower sex drive
• Reduced muscle mass
• Lack of energy
• Depression 

In males: 

• Erectile dysfunction
• Smaller testicles
• Reduced body hair
• Low sperm count 
• Hot flashes

In females:

• Difficulty conceiving
• Irregular menstruation
• Vaginal dryness
• Fragile skin and thinning hair (which are also more common with age) 

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Seek an expert opinion

If you want to know whether your hair and skin changes are symptoms of a hormonal deficiency, the aging process or both, consult a board-certified dermatologist. You can access expert diagnoses and personalized treatment plans for thousands of conditions at getcortina.com.

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