I'm A Dietitian This Is Why I Don't Recommend Taking Melatonin Nightly

Walk the aisles of any U.S. pharmacy and you'll likely see melatonin supplements in many forms—from fast-dissolve tablets to sweet gummies. Most Americans won't find this unusual, but it's sure to raise a few eyebrows among health experts coming from abroad, like Cliona Byrnes, R.D., a registered dietitian nutritionist who previously worked in Dublin.

"In Ireland, you can't buy melatonin on a shelf or online. It has to be prescribed by a doctor," Byrnes explains. After taking the client's needs and health history into account, she adds, most doctors only prescribe it for short-term use. If you try to order melatonin supplements online, you risk getting them confiscated by customs. And this isn't just Ireland being needlessly strict; most countries outside of the U.S. and Canada require a prescription for the sleep aid.

Melatonin is a hormone that our bodies make naturally in small amounts (about 0.3 milligrams) to set our sleep-wake cycles. When melatonin is released by our brain's pineal gland and a few other organs, we start to feel drowsy. But if you regularly take exogenous (aka supplemental) melatonin, it's unclear how that will affect the rest of your hormones. There's some research to show that melatonin supplements can negatively affect the function of hormones like estrogen and male growth hormone, for example.

While taking melatonin for a quick reset (if you're traveling across multiple time zones, for example) can help you adjust to a new bedtime, there's little credible evidence that it will improve your overall sleep quality. Instead, it can leave you feeling groggy, foggy, and dazed the day after a subpar rest—another reason it's not as widely available in other countries.

"The main concern for me," Byrnes adds, "Is that you can develop a tolerance to it, so over time you need a higher and higher dose. In the long run, you're just making it so much harder to fall asleep naturally."

When Byrnes arrived in the States to work as a nutrition researcher at mbg, she was surprised to find not only melatonin online and on the shelves of stores she visited—but very high doses of it. Some melatonin supplements contain 10 milligrams of the hormone or more—that's 33 times higher than the amount your body produces naturally. "It blew my mind a bit, to be honest," she says. "The contrast was so stark."

In Ireland, when somebody has trouble sleeping through the night, instead of taking high doses of melatonin, they may be directed to make a number of diet and lifestyle tweaks.

For example, avoiding eating dinner too close to bedtime, cutting down on alcohol consumption, and cutting off caffeine early can all promote deeper sleep. Foods containing tryptophan (turkey, chicken, eggs, pumpkin seeds, beans, peanuts, and leafy green vegetables) and/or magnesium (whole grains, dark leafy vegetables, nuts and seeds, bananas, yogurt, and milk) can also help prime the body for bed, so Byrnes recommends them as nighttime snacks. An essential mineral that your body needs to function, magnesium even supports the production of certain calming hormones, including melatonin!*

And for those looking for a relaxing supplement to complement their bedtime routine—one that is nonhormonal and safe to take nightly—Byrnes chooses mbg's sleep support+ over melatonin any day. "The combination of magnesium, jujube, and PharmaGABA® is science-backed and can enhance sleep quality so you fall asleep faster, stay asleep longer, and wake up feeling rejuvenated,"* she says.

Unlike melatonin supplements, sleep support+ is also non-habit-forming and comes with few to no side effects according to hundreds of customer reviews.*