Melatonin PillsMelatonin is generally safe in recommended doses, the Mayo Clinic says of the synthetic hormone that’s available in pill form. The recommended dose is no more than 5 mg per day for a duration of up to two years.

Even though the melatonin supplement is generally safe, it is considered unsafe under certain conditions. The supplement also comes with a handful of warnings and potential side effects.

Why would you want to take melatonin in the first place?

Your brain’s natural melatonin production kicks into high gear in darkness and low gear in the light, thereby linking the hormone to your body’s sleep-wake cycle and the regulation of various bodily functions.

One of the main uses for the synthetic form of the hormone has been to help people fall asleep, according to MedLinePlus.com.  Melatonin has been proven effective for sleeping problems in children with mental retardation and autism as well as sleep disorders for people who are blind.

It may possibly be effective for insomnia, jet lag, cluster headaches, reduction of anxiety prior to surgery, and low blood platelet counts. In addition, it may help certain cancer medications work more effectively and help older adults fall asleep after they stop taking benzodiazepines.

Other possible uses include: reducing withdrawal symptoms and cravings for cigarettes, decreasing sunburn when used topically prior to sun exposure, and decreasing symptoms of the movement disorder tardive dyskinesia.

Although people have used melatonin for other conditions, not all of its uses have proven results. Melatonin is ranked possibly ineffective for sleep schedule adjustment in those who perform shift work and likely ineffective for depression.

Additional conditions may or may not be helped by melatonin, since not enough evidence exists to rate its effectiveness either way. These conditions include: symptoms of menopause, sleep issues associated with ADHD, epilepsy, insomnia brought about by high blood pressure medications, and ringing in the ears.

While melatonin may help alleviate cluster headaches, there’s not enough evidence to say it does the same for migraines or idiopathic stabbing headaches that cause a sharp, focused pain. Melatonin may or may not be effective for osteoporosis, chronic fatigue syndrome, irritable bowel syndrome, fibromyalgia, aging, and birth control.

What does the FDA have to say about melatonin?

Because melatonin is available as a supplement, it does not fall under the strict regulation of the U.S. Food and Drug Administration. The lack of strict regulation means the purity and strength of melatonin supplements can vary considerably, as can the result from taking them.

What are melatonin’s side effects?

Side effects can include irritability, dizziness, drowsiness, fatigue, headaches, and sleeplessness. Fatigue may be most common if you take high doses or use melatonin in the morning, disrupting your body’s usual sleep-wake cycle.

Other side effects that have been reported are nightmares or particularly vivid dreams, sleepwalking, and issues with walking and balance while awake. Disorientation has been reported, as have digestive issues. These include nausea, pain and vomiting, an increase in appetite or alteration in taste, and diarrhea.

Skin rashes are possible, especially for those who may be allergic to melatonin. The supplement may also cause an increase in urination and risk of inflammation along with a decrease of mental functioning and performance.

Mood changes are a potential risk, as are hallucinations and paranoia. Such psychotic symptoms, however, may have resulted from an overdose of the hormone. Because it is a hormone, hormonal effects are also the list of potential side effects. These include changes in the levels of various other hormones and their side effects, such as an increased breast size and decreased sperm count in men and a decreased libido across the board.

Who should be extra cautious or avoid using melatonin?

Women who are breastfeeding or pregnant top the list of those who should avoid melatonin. Women attempting to become pregnant should do the same, as the supplement may increase the risk of developmental disorders in fetuses.

Others should remain under the close supervision of a healthcare professional while taking the supplement, as melatonin may exacerbate existing conditions. These include people with seizure disorder, psychotic disorders or depression, and bleeding disorders. Those with low blood pressure should also stay in constant contact with a healthcare professional if using melatonin.

Anyone at risk for cardiovascular disease or high cholesterol levels requires constant monitoring. The same holds true for those with Type 1 diabetes, hypoglycemia, and glaucoma. Melatonin may not mix well with certain medications and drugs, such as benzodiazepines and other CNS depressants, alcohol, and anesthetics.

Due to melatonin’s tendency to make people sleepy, you should never use the supplement while driving, operating heavy machinery, or otherwise performing activities that require acute alertness and concentration.

The safest way to go about taking any supplement is to check with your primary care physician. He or she can outline any additional risks based on your specific health profile, as well as other interactions melatonin may produce based on any additional medications or supplements you may be taking.