From
www.mindbodyconsult.com. Bold emphasis mine. I do not claim to know with any degree of certainty the accuracy of this information.
Melatonin
Psychoactive
Description: Hormone naturally secreted by pineal gland. Derived from pineal parenchymal cells from the same metabolic pathway that gives rise to serotonin.
Method of Action: Neurohormone which inhibits sympathetic nervous system action and stimulates parasympathetic nervous system causing reset of biological clock (circadian rhythms). Increases effect of GABA and raises brain serotonin levels inhibiting the sympathetic nervous system. Protects cells against radical-mediated damage. .05 mg produced daily in healthy persons.
Indications and Usage: Sleep Disorders (especially East-West Jet-Lag and insomnia related to Dysthymia and Major Depression); Improves sleep efficacy; Mild-Moderate Depression; Seasonal Affective Disorder (SAD) in conjunction with phototherapy; Circadian Rhythm Disorders; Menstrual Discomfort; Infertility; Alzheimer’s Disease; Bipolar Disorder; Substance Abuse Recovery; Alcoholism; Beneficial effect on deleterious effects of aging; Reduces formation of gastric lesions; Reduces deleterious effects of chemotherapy; May strengthens immune system with corresponding benefits on certain cancers; Hypertension and cardiovascular disease; Infertility. Use in many of the above areas may be complicated and highly dependent of individual variables. Professional supervision is recommended.
Contraindications: Do not use this product if you are pregnant or lactating. Supplemental melatonin may interfere with ovulation and conception. Some types of depression may be worsened by taking supplemental melatonin and close monitoring is advised. Melatonin supplementation may aggravate autoimmune disorders such as arthritis and severe allergies. Melatonin shrinks arteries and may be contraindicated in persons with cardiovascular disease. Children have high levels of melatonin and should not normally receive melatonin supplements. The effects of steroid drugs such as cortisone and dexamethasone may be counteracted by supplemental melatonin. Immune-system cancers such as lymphoma and leukemia may be further stimulated by melatonin supplementation. Persons under 40 years of age should avoid melatonin supplementation when possible.
Dosage and Administration: Sleep, Jet Lag, Anti-Aging: 0.2 to 3.0 mg in synthetic, timed-release form daily taken twenty minutes prior to bedtime (at the same time each day) along with 100 mg. niacinamide, 750 mg. calcium, 500 mg. magnesium and (in the am.) 25-50 mg. vitamin B-6. Shift work adaptation and immune stimulation require higher doses (1-5 mg. and 2-20 mg. respectively) and should be taken under professional supervision. Avoid melatonin products that have added ingredients (such as vitamin B-6.) Do not take melatonin at times other than bedtime. Use of non-timed-release forms of melatonin may result in early wakening, as melatonin-induced decrease in body temperature will reverse resulting in wakening. (Additional melatonin can be taken up to 3 hours before scheduled wake-up time.) Note: Optimal dose is highly individual and can only be accurately determined by laboratory testing as close to bedtime as possible and over two hours. Time of year also influences amount needed as decreasing sunlight (in winter months) tends to increase endogenous levels of melatonin in brain. If you experience drowsiness in the morning that appears to be melatonin-related decrease dosage.
Clinical Effect In: Within 30 minutes. Half-life of melatonin is short 30 to 40 minutes.
Adverse Reactions:
No negative laboratory findings have been reported. Supplemental melatonin may increase levels of depression in some individuals (possibly those prone to seasonal affective disorder). No sleep architecture changes noted.
Rare reversible adverse reactions including insomnia, vivid dreams, nightmares, depression, next-day fatigue and headache have been reported. Melatonin may cause decreased estrogen, testosterone and thyroid hormone. Research has not established whether melatonin supplementation could create hormonal dependency.
Known Interactive Effects: Do not use supplemental melatonin if there is reason to suspect your natural levels of melatonin are already high. May decrease absorption of estrogen. Persons taking monoamine oxidase inhibitors, beta-blocking drugs and steroid medications should not take supplemental melatonin. Persons taking antidepressant and antianxiety medications are cautioned that melatonin supplementation may enhance the effects of these drugs that also commonly raise melatonin levels in the brain.
Melatonin levels can be depleted by the use of certain drugs and substances including: Fluoxetine (Prozac), nonsteroidal anti-inflammatory drugs, beta-blocker, calcium antagonists and calcium channel blockers, antihypertensive medication, vitamin B-12, caffeine, steroids, tobacco, alcohol.