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This
hormone is made by the pineal gland, a pea-sized structure
in the brain. Contrary to the claims of some, secretion of
melatonin does not necessarily decrease with age. Instead, a
number of factors, including light and many common
medications, can affect melatonin secretion in people of any
age.
Melatonin
supplements can be bought without a prescription. Some
people claim that melatonin is an anti-aging remedy, a sleep
remedy, and an antioxidant (antioxidants protect against
"free radicals," naturally occurring oxygen-related
molecules that cause damage to the body). Early test-tube
studies suggested that, in large doses, melatonin might be
effective against free-radicals. However, cells produce
antioxidants naturally, and in test-tube experiments, cells
reduce the amount they make when they are exposed to
additional antioxidants.
Claims
that melatonin can slow or reverse aging are very far from
proven. Studies of melatonin have been much too limited to
support these claims and have focused on animals, not
people.
Research
on sleep shows that melatonin does play a role in our daily
sleep/wake cycle, and that supplements can improve sleep in
some cases. If melatonin is taken at the wrong time, though,
it can disrupt the sleep/wake cycle. Other side effects may
include confusion, drowsiness, and headache the next
morning. Animal studies suggest that melatonin may cause
some blood vessels to constrict, a condition that could be
dangerous for people with high blood pressure or other
cardiovascular problems.
These
side effects are important to keep in mind since the dose
of melatonin usually sold in stores -- 3 milligrams -- can
result in amounts in the blood up to 40 times higher than
normal.
What
long-term effects such high concentrations of melatonin may
have on the body are still unknown. Until researchers find
out more, caution is advised.
Part
8: Testosterone
Adapted
from the National Institute on
Aging
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