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Although melatonin is a hormonal chemical produced by your body and valerian is a herb-like plant, you can take both as supplements for treating insomnia. Melatonin and valerian also have other potential medicinal uses. Consult your doctor before taking either supplement to treat any health problem, because both substances can cause possible health risks and drug interactions.

Benefits

Both melatonin and valerian have the potential to treat insomnia and cluster or migraine headaches. Valerian is sometimes also recommended to treat anxiety and stress. On the other hand, melatonin has many other possible uses. You might take melatonin to help treat depression, jet lag, macular degeneration and glaucoma, sunburns, dementia, seasonal affective disorder, tardive dyskinesia, epilepsy, fibromyalgia and sarcoidosis. Additionally, melatonin may ease the side effects of chemotherapy and drug withdrawal, as well as support cancer and HIV or AIDS treatments, notes the Memorial Sloan-Kettering Cancer Center. No conclusive medical evidence supports the use of melatonin or valerian to effectively treat or prevent any health condition, however.

Dosages

A typical dose of valerian is 2 to 3 grams of dried herb or 270 to 450 milligrams of liquid extract one-half to one hour prior to bedtime for insomnia, says the University of Pittsburgh Medical Center. For anxiety, you can take valerian twice each day at a lower dosage. Because your body normally produces and releases melatonin during nighttime, you should also take the supplement before bed. Suggested dosage is 1 to 3 milligrams of melatonin about one or two hours prior to bedtime, advises the University of Michigan Health System. Ask your doctor about the dose of valerian or melatonin that's right for you before taking either supplement.

Functions

Valerian may work in a similar manner to sedative-like drugs like Valium, suggests the University of Pittsburg Medical Center. Valerian appears to increase the concentration of gamma aminobutyric acid, or GABA, in the brain, which has a calming effect, explains the University of Maryland Medical Center. Melatonin has more complicated functions, although relatively little is known about melatonin’s actual actions in the body. Created by the brain's pineal gland, melatonin appears to regulate the sleep-wake cycle and act as a powerful antioxidant to fight off free radicals. Melatonin seems to stimulate lymphocytes in the immune system and inhibit the growth of cancer cells, notes the Memorial Sloan-Kettering Cancer Center. People who have insomnia, work at night, have heart disease or suffer from depression and schizophrenia all appear to have low levels of melatonin.

Scientific Research

Taking melatonin can improve sleep for elderly people, according to a 1996 study published in the Journal of the American Geriatric Society. Another study reported in the Journal of Clinical Psychiatry in 2000 found that people with schizophrenia experienced better sleep after taking melatonin supplements, notes the University of Michigan Health System. Melatonin inhibits the growth of human breast cancer cells and melanoma in mice, according to in vitro studies published in Cancer Research in 1997 and Melanoma Research in 2001. Melatonin also inhibited endometrial cancer cells by interfering with estrogen receptors in a 2008 study published in the Journal of Obstetrics and Gynaecology Research, says the Memorial Sloan-Kettering Cancer Center. Taking 3 milligrams of melatonin per day also helped to prevent migraine headaches in a 2004 study reported in Neurology.

Valerian extract influenced GABA levels and reduced anxiety in clinical trials reported by Planta Medica in 1989 and 1994. Studies of valerian's potential to treat insomnia have yielded mixed results, however. A 1996 double-blind clinical trial in Germany found that taking 600 milligrams of valerian extract one hour before bed helped to treat insomnia, notes the University of Pittsburgh Medical Center. Another study reported in the European Journal of Medical Research in 2003 found that taking valerian before bed was equally effective as the conventional sedative medication oxazepam. But a 2007 review of studies on valerian that was published in Sleep Medicine Reviews determined that the herb isn't an effective insomnia treatment.

Dangers

Melatonin could cause drowsiness, confusion or disorientation, unsafe drops in body temperature and stomach cramps. Taking melatonin supplements could decrease sperm counts in men, increase the risk of seizures in children with neurological disorders and affect blood glucose levels in people with diabetes. Melatonin might also interact negatively with medications like nifedipine and fluvoxamine, as well as blood-thinners like Coumadin or Plavix. No serious side effects have been reported from taking valerian at recommended doses, but the herb might potentially increase the effects of sedative medications like benzodiazepines.