Melatonin is an important hormone that is secreted by the pineal gland in the
brain. Since its identification in 1958, studies have shown that melatonin plays
a crucial role in ordering the complex hormone secretion patterns that regulate
the body's circadian rhythm. Melatonin also helps control sleeping and waking
periods, because its release is stimulated by darkness and suppressed by light.
It also controls the timing and release of female reproductive hormones,
affecting menstrual cycles, menarche, and menopause.
Overall levels of melatonin in the body also contribute to the process of
aging. The standard rhythmic pattern of melatonin levels are absent until about
3 months of age. After that, the nocturnal levels of melatonin are at their
highest for the first few years and then begin to decline as puberty begins.
After puberty, nocturnal melatonin levels are relatively stable throughout
adulthood and then fall as people age. In old age, the nocturnal rise in
melatonin may be barely detectable. Because melatonin opposes the degeneration
caused by high levels of corticosteroids (e.g., protein catabolism, suppressed
immune function, and altered blood glucose metabolism), higher melatonin levels
may help promote health and extend life span.
Studies show that jet lag is most likely caused by a disrupted circadian
rhythm that can be effectively adjusted by using melatonin. Insomnia that is
seen in the elderly and in some children with sleeping disorders is usually
caused by low melatonin levels. That, too, can be treated with the proper
supplementation. Childhood diseases that may cause melatonin-related sleep
disorders include autism, epilepsy, Down's syndrome, and cerebral palsy.
Melatonin supplementation can also benefit blind people whose sleeping rhythms
are disturbed. Melatonin is not effective as a sleeping aid for persons with
normal melatonin levels.
Several studies have shown how melatonin levels shift during monthly
menstrual cycles. Nocturnal melatonin is highest during the premenstrual period
and lowest during the midmenstrual period. It is thought that rising melatonin
levels may bring on menstruation and lowering ones may bring on a surge of
luteinizing hormone and ovulation. Administering melatonin prior to the midcycle
surge of luteinizing hormone appears to block ovulation, leading to speculation
about the use of melatonin as a natural contraceptive.
Melatonin also has antioxidant, antiestrogenic, and may have oncostatic
properties. As an antioxidant, melatonin appears to be able to neutralize
hydroxyl, the most damaging of all oxygen-based free radicals. Studies show that
melatonin may help prevent or treat some hormonally related cancers, such as
breast cancer and prostate cancer.
Many studies have shown that some patients suffering from depression have
lower-than-normal melatonin levels. Seasonal affective disorder (SAD) is often
effectively treated with phototherapy, and research has shown that SAD patients
often have delayed melatonin rhythms in the winter. While some forms of
depression may have direct links to melatonin levels, other types of depression
have not responded well to melatonin treatment. Exaggerated depressive symptoms
have been reported in some cases of depressed patients receiving daytime
melatonin supplements. Melatonin has increased psychotic behavior in some
Melatonin is a hormone manufactured by serotonin and secreted by the pineal
gland. It is an indole, like the simple amino acid,
Melatonin can be taken in tablet, capsule, and sublingual tablet
- Used to restore sleeping patterns and fatigue caused by jet lag
- As a sleeping aid for those who suffer from insomnia as a result of
low melatonin levels (e.g., elderly and some children with sleep disorders)
- May be beneficial for treatment of depression related to low melatonin
levels (e.g., SAD)
- Preliminary studies show it may be useful in multiple sclerosis, SIDS,
coronary heart disease, epilepsy and postmenopausal osteoporosis.
|Dosage Ranges and Duration of
Official dosage ranges have not yet been set for melatonin supplementation.
Sensitivity to melatonin may vary from individual to individual. For those
especially sensitive to it, lower doses may work more effectively than the
standard amount. Higher doses could cause anxiety or irritability.
For treatment of insomnia, a dose of 3 mg taken an hour before bedtime is
usually effective, although dosages as low as 0.1 to 0.3 mg may improve sleep
for some people. If 3 mg a night is not effective after three days, try 6 mg one
hour before bedtime. An individually effective dose should produce restful sleep
and no daytime irritability or fatigue. For treatment of jet lag, take 5 mg of
melatonin one hour before bedtime upon arrival at new location; repeat for the
first five days. Long-term melatonin supplementation should not be carried out
without a health care provider's supervision.
There are no known serious side effects to regulated melatonin
supplementation. Some people may experience vivid dreams or nightmares. Overuse
or incorrect use of melatonin could disrupt circadian rhythms. Long-term effects
have not been well studied. In rats, melatonin decreases T4 and T3 uptake
Melatonin can cause drowsiness if taken during the day. If morning drowsiness
is experienced after taking melatonin at night, reduce dosage levels. In some
cases of depression, daytime doses of melatonin can increase depression. May be
contraindicated for those with autoimmune disorders and immune system cancers
(e.g., lymphoma, leukemia). Because melatonin suppresses corticosteroid
activity, those who are taking corticosteroids for anti-inflammatory or immune
suppressive purposes (e.g., transplant patients) should exercise caution with
melatonin supplementation. Melatonin could interfere with fertility. It is also
contraindicated during pregnancy and lactation. Lack of sleep and insufficient
exposure to darkness may suppress natural production of
Melatonin impaired the efficacy of both methoxamine and clonidine by relaxing
vascular smooth muscle through an undetermined mechanism in an ex-vivo
experiment using thoracic aorta excised from male rats (Weekley 1991). It is not
known whether exogenous melatonin can antagonize the effects of methoxamine and
clonidine in humans.
In an experimental rat study, exogenous melatonin (0.25 mg/kg/day) abolished
the antidepressant effects of desipramine and fluoxetine possibly through
interference with tryptophan-2,3-dioxygenase activity (Walsh and Daya 1998).
More research is needed to determine if exogenous melatonin counteracts the
effects of antidepressants in humans.
Preliminary research suggests that tamoxifen plus high-dose melatonin may be
of benefit in patients with metastatic solid tumors or breast cancer (Lissoni et
al. 1995A; Lissoni et al. 1996). More research is needed to confirm these
The combination of melatonin (100 mg/day) with triazolam improved subjective
sleep quality in healthy subjects (Ferini-Strambi et al. 1993). Another case
study reported that melatonin (1 mg/day controlled release) improved sleep
quality and enabled a patient to cease long-term benzodiazepine therapy (Dagan
et al. 1997).
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