various glands throughout the body. The primary male sex hor-
mone is testosterone. Testosterone and other related hormones
that have “masculinizing” effects are produced primarily in the tes-
ticles. These same hormones are the cause of many changes that
occur in puberty in boys. The hormones that cause acne and beard
growth also can trigger the beginning of baldness. Testosterone is
also produced in women from the adrenal glands and the ovaries,
and it is produced in lower concentrations than the testicles pro-
duce the hormone in men. In women, most of the testosterone is
converted into estrogen.
The hormone believed to be most directly involved in androge-
netic alopecia is dihydrotestosterone (DHT). DHT is formed by the
action of the enzyme 5-alpha reductase (5AR) on testosterone, and
it binds to special receptor sites on the cells of hair follicles to
cause the specific changes associated with balding.
The presence of androgens (steroid like substances), testosterone
(considered an androgen), and DHT cause some hair follicles to
regress and die. In addition to the testicles, the adrenal glands
located above the kidneys produce androgenetic hormones; this is
true for both sexes. In females, ovaries are the major source of hor-
mones that can affect hair. Androgenetic hormones stimulate many
of the male sex characteristics we see in adult men. Androgens like
testosterone, are converted into estrogens in women, which make
women develop their typical female sex characteristics.
Baring hair at the beach
The beach is an excellent place to observe hair patterns. Have you ever noticed
that men with hairy backs and shoulders often have a bald head or a hair replace-
ment system?
This indicates that the gene for hair on the back and shoulders is separate from the
gene for hair on the scalp. Although DHT acts like fertilizer for shoulder and back
hair, it causes reduction of head hair in many men.
The beach is an excellent place to observe hair patterns. Have you ever noticed
that men with hairy backs and shoulders often have a bald head or a hair replace-
ment system?
This indicates that the gene for hair on the back and shoulders is separate from the
gene for hair on the scalp. Although DHT acts like fertilizer for shoulder and back
hair, it causes reduction of head hair in many men.
Early in the 20th century, a psychiatrist discovered the specific
relationship between testosterone and hormone-induced hair loss.
The doctor noted that the identical twin brother of one patient was
profoundly bald while the mentally ill twin had a full head of hair.
The doctor decided to determine the effect of treating his patient
with testosterone, and injected him (the hairy twin) with the hor-
mone. Within weeks, the hairy patient began to lose all but his
wreath of permanent hair, just like his twin. The doctor stopped
administering testosterone, but his patient never regained his head
of hair.
Testosterone and DHT
The cause of pattern thinning in men is primarily related to two
sex hormones, testosterone and DHT. The body converts testos-
terone into the hormone DHT by way of an enzyme found in vari-
ous tissues throughout the body.
In men with the genes for ANA, DHT increases the resting (telogen)
phase and decreases the growing (anagen) phase of hair. (We
explain the growth cycle more in the earlier section, “Examining
uniform hair loss.”) Consequently, as a man ages, less hair grows at
any given time, and the hair starts to thin as a normal consequence
of aging, especially in men with ANA. Eventually, baldness occurs.
In men who haven’t inherited the ANA balding genes, the combina-
tion of DHT and testosterone doesn’t cause hair loss and may have
a lesser impact on aging hair.
Some areas of the scalp are more susceptible than others to the
affects of DHT. For example, the hormone doesn’t usually affect
hair on the back and side of the head, which is why these areas
retain hair. The term “male pattern thinning” is used because hair
loss occurs in a pattern — the back and side of the head retain hair
but the crown and frontal areas may lose it. The loss may be con-
fined only to the frontal area or the crown area based upon the
genetics that are inherited from the family tree.
DHT does play a role in the growth of beard hair; body hair; and
eyebrow, nose, and ear hair, but doctors don’t clearly understand
that role. Sometime after puberty, male hormones trigger a biologi-
cal clock that makes hair grow in these areas.
In men, the enzyme 5AR activity is higher in the balding area.
Women have half the amount of 5AR overall as compared to men
but have higher levels of the enzyme aromatase, especially in their
frontal hairlines. Aromatase decreases the formation of DHT, and
its presence in women may help to explain why female hair loss is
somewhat different than hair loss in males. (The section
“Examining Hair Thinning in Women” later in this chapter takes an
in-depth look at female hair loss.)
The only way to stop DHT is to block it with finasteride or dutas-
teride, drugs that interfere with DHT production. (See Chapter 9 for
more on DHT and the drugs that fight hair loss.)
At present, only finasteride has been approved by the Federal Drug
Administration (FDA). Dutasteride is still being evaluated for its
safety and effectiveness for hair loss in young men. There are some
reports that dutasteride has significant effects on male sperm pro-
duction; as such, it may not be approved for men experiencing hair
loss. Blocking DHT in women with dutasteride hasn’t been shown
to prevent or reverse female hair loss or hair thinning. Its safety
with regard to breast cancer, particularly in women who carry the
breast cancer producing BRCA genes, is not understood.
Steroids and similar products
Anabolic steroids, the kind bodybuilders sometimes (illegally) use,
can cause hair loss if you’re genetically predisposed to it. And
there’s a direct link between taking human growth hormone (HGH)
and hair loss — probably caused by the same underlying mecha-
nisms as steroid use. Women body builders who take steroids
develop some male sex characteristics and some experience hair
loss.
HGH has become a trendy anti-aging tool. More and more men are
using it as a fountain of youth. Some men combine steroids and
HGH because they make them feel better and stronger. But we have
seen many men on HGH in our offices with “unexplained hair loss.”
No real mystery there.
Many men who take steroids also take Propecia (a DHT blocker) to
offset the negative effects of DHT. Propecia blocks DHT and causes
a rise in systemic testosterone by up to 18 percent. Indirectly,
Propecia may help muscle building if DHT levels go down (from the
Propecia) and testosterone levels go up to compensate.
Testosterone is a much stronger hormone than DHT, and the sum
of the effects of the rise in serum testosterone from taking a DHT
blocker such as Propecia and the steroids may very well produce
more hair loss, not less.
Everyone is different, so we can’t conclude if the muscle mass that
the men are seeking from steroid use can be offset. Recently,
Propecia was found to mask the blood measurements for other
steroids when used in athletes, which is why its use is banned for
professional athletes.
Fitness-focused individuals may take the following products for
their physical benefits, but these products can also cause hair loss:
Whey-based nutritional supplements: The use of growth hor-
mones in some dairy cows affects the milk they produce and,
in turn, the whey (a byproduct of cheese production). Even if
a person doesn’t take steroids, these products may have some
steroid-like impact from the milk source. People who take
whey-based nutritional supplements may experience steroid-
related side effects if the cows were treated with steroids. It is
unclear how much of these steroids, if any, will survive transit
through the stomach to be eventually absorbed into the body.
DHEA: Some people take DHEA, which is found in the nutri-
tional section of many health food and vitamin stores and
doesn’t require a prescription. The DHEA sold in stores is
reportedly made by the adrenal glands and claims to help
reduce body fat stores while promoting sugar metabolism. It
also can cause hair loss. Other available supplements claim
testosterone or steroid-like characteristics. The desire for
men to add body mass and/or prevent hair loss drives them
to seek out such products.
Dose-pack steroids: A short course of steroids for medical
reasons (4–5 days) should not have an impact producing
hair loss.
Prednisone: People who are on this steroid for chronic med-
ical problems (arthritis, various autoimmune diseases) will
experience hair loss.
Hair loss is also a risk for women who use steroids, if they’re pre-
disposed to the condition. Women usually take steroids for dis-
eases that occur later in life, such as autoimmune disease,
temporal arteritis, rheumatoid arthritis.
relationship between testosterone and hormone-induced hair loss.
The doctor noted that the identical twin brother of one patient was
profoundly bald while the mentally ill twin had a full head of hair.
The doctor decided to determine the effect of treating his patient
with testosterone, and injected him (the hairy twin) with the hor-
mone. Within weeks, the hairy patient began to lose all but his
wreath of permanent hair, just like his twin. The doctor stopped
administering testosterone, but his patient never regained his head
of hair.
Testosterone and DHT
The cause of pattern thinning in men is primarily related to two
sex hormones, testosterone and DHT. The body converts testos-
terone into the hormone DHT by way of an enzyme found in vari-
ous tissues throughout the body.
In men with the genes for ANA, DHT increases the resting (telogen)
phase and decreases the growing (anagen) phase of hair. (We
explain the growth cycle more in the earlier section, “Examining
uniform hair loss.”) Consequently, as a man ages, less hair grows at
any given time, and the hair starts to thin as a normal consequence
of aging, especially in men with ANA. Eventually, baldness occurs.
In men who haven’t inherited the ANA balding genes, the combina-
tion of DHT and testosterone doesn’t cause hair loss and may have
a lesser impact on aging hair.
Some areas of the scalp are more susceptible than others to the
affects of DHT. For example, the hormone doesn’t usually affect
hair on the back and side of the head, which is why these areas
retain hair. The term “male pattern thinning” is used because hair
loss occurs in a pattern — the back and side of the head retain hair
but the crown and frontal areas may lose it. The loss may be con-
fined only to the frontal area or the crown area based upon the
genetics that are inherited from the family tree.
DHT does play a role in the growth of beard hair; body hair; and
eyebrow, nose, and ear hair, but doctors don’t clearly understand
that role. Sometime after puberty, male hormones trigger a biologi-
cal clock that makes hair grow in these areas.
In men, the enzyme 5AR activity is higher in the balding area.
Women have half the amount of 5AR overall as compared to men
but have higher levels of the enzyme aromatase, especially in their
frontal hairlines. Aromatase decreases the formation of DHT, and
its presence in women may help to explain why female hair loss is
somewhat different than hair loss in males. (The section
“Examining Hair Thinning in Women” later in this chapter takes an
in-depth look at female hair loss.)
The only way to stop DHT is to block it with finasteride or dutas-
teride, drugs that interfere with DHT production. (See Chapter 9 for
more on DHT and the drugs that fight hair loss.)
At present, only finasteride has been approved by the Federal Drug
Administration (FDA). Dutasteride is still being evaluated for its
safety and effectiveness for hair loss in young men. There are some
reports that dutasteride has significant effects on male sperm pro-
duction; as such, it may not be approved for men experiencing hair
loss. Blocking DHT in women with dutasteride hasn’t been shown
to prevent or reverse female hair loss or hair thinning. Its safety
with regard to breast cancer, particularly in women who carry the
breast cancer producing BRCA genes, is not understood.
Steroids and similar products
Anabolic steroids, the kind bodybuilders sometimes (illegally) use,
can cause hair loss if you’re genetically predisposed to it. And
there’s a direct link between taking human growth hormone (HGH)
and hair loss — probably caused by the same underlying mecha-
nisms as steroid use. Women body builders who take steroids
develop some male sex characteristics and some experience hair
loss.
HGH has become a trendy anti-aging tool. More and more men are
using it as a fountain of youth. Some men combine steroids and
HGH because they make them feel better and stronger. But we have
seen many men on HGH in our offices with “unexplained hair loss.”
No real mystery there.
Many men who take steroids also take Propecia (a DHT blocker) to
offset the negative effects of DHT. Propecia blocks DHT and causes
a rise in systemic testosterone by up to 18 percent. Indirectly,
Propecia may help muscle building if DHT levels go down (from the
Propecia) and testosterone levels go up to compensate.
Testosterone is a much stronger hormone than DHT, and the sum
of the effects of the rise in serum testosterone from taking a DHT
blocker such as Propecia and the steroids may very well produce
more hair loss, not less.
Everyone is different, so we can’t conclude if the muscle mass that
the men are seeking from steroid use can be offset. Recently,
Propecia was found to mask the blood measurements for other
steroids when used in athletes, which is why its use is banned for
professional athletes.
Fitness-focused individuals may take the following products for
their physical benefits, but these products can also cause hair loss:
Whey-based nutritional supplements: The use of growth hor-
mones in some dairy cows affects the milk they produce and,
in turn, the whey (a byproduct of cheese production). Even if
a person doesn’t take steroids, these products may have some
steroid-like impact from the milk source. People who take
whey-based nutritional supplements may experience steroid-
related side effects if the cows were treated with steroids. It is
unclear how much of these steroids, if any, will survive transit
through the stomach to be eventually absorbed into the body.
DHEA: Some people take DHEA, which is found in the nutri-
tional section of many health food and vitamin stores and
doesn’t require a prescription. The DHEA sold in stores is
reportedly made by the adrenal glands and claims to help
reduce body fat stores while promoting sugar metabolism. It
also can cause hair loss. Other available supplements claim
testosterone or steroid-like characteristics. The desire for
men to add body mass and/or prevent hair loss drives them
to seek out such products.
Dose-pack steroids: A short course of steroids for medical
reasons (4–5 days) should not have an impact producing
hair loss.
Prednisone: People who are on this steroid for chronic med-
ical problems (arthritis, various autoimmune diseases) will
experience hair loss.
Hair loss is also a risk for women who use steroids, if they’re pre-
disposed to the condition. Women usually take steroids for dis-
eases that occur later in life, such as autoimmune disease,
temporal arteritis, rheumatoid arthritis.
