But the researchers found that insomniacs often take doses that are 10 times higher than their body requires, making the melatonin less effective. Lorraine A. Fitzpatrick, MD, a Mayo Clinic physician, tells WebMD that the news is exciting, but cautions patients about proper doses. Frequently, we see people taking melatonin and getting side effects or hangovers. They may think they're taking the right dose, but they wake up groggy and not able to function. I encourage all of my patients to talk to their doctors about all of the medications they're taking.
Interactions can occur with prescription medications that change the affects of drugs.
Wurtman also offers warnings. It's important to let your physician know you're taking it. While melatonin purchased from the pharmacy or health food store is very safe, Wurtman says, higher doses can cause nightmares and possibly can interact with prescription medications. Wurtman notes that most older people with insomnia don't have trouble falling asleep, because they're exhausted from not sleeping the night before. For these people, low doses of melatonin may be the answer.