An Integrative MD Explains The Sneaky Link Between Melatonin & Weight Gain

Apparently, melatonin may affect weight gain—well, depending on what time you take it. 

An Integrative MD Explains The Sneaky Link Between Melatonin & Weight Gain

Melatonin is one cool hormone. Not only does it send sleepytime signals to your body but it also has antioxidant and anti-inflammatory properties that can benefit mitochondrial health and even skin care. Not to mention, melatonin has legs in fertility: “One of the richest sites of melatonin in the body is the ovaries,” midwife and integrative medicine doctor Aviva Romm, M.D., says on the mindbodygreen podcast. “And fertility actually depends on healthy melatonin levels in the brain and in the ovaries.” We repeat: Melatonin is a pretty cool hormone to have around. 

But when it comes to taking melatonin supplements, some concerns do arise: There’s the dosage point—where experts pose that taking many milligrams over time may affect your other hormones—and there’s a much sneakier hitch Romm says is important to keep in mind. 

Apparently, melatonin may affect weight gain—well, depending on what time you take it.

The link between melatonin and weight gain. 

When melatonin gets released at night, the hormone sends signals to your body that it’s time to start winding down. As a result, your body goes into “rest mode,” with a focus on repair and restoration—and daytime functions like digestion are essentially turned off. (That’s why experts say to avoid eating late at night if you can, as your metabolism naturally slows.) 

When you take melatonin, you kick start this rest and recover process. So if you take the sleep aid, say, right after eating, you could harp on your digestion without even knowing it. “If you eat your dinner late, let's say 7:30 p.m. and then you take your melatonin at 8:00 p.m., you may be quieting your metabolism a little bit,” says Romm. “You may not get as much digestive fire, and it may actually affect weight gain.” 

Of course, there’s an easy fix: Just space out the time between eating and taking your melatonin! “If that means you need to bump your dinner a little earlier or take your melatonin a little later, that seems to be the antidote,” Romm adds. 

It’s not that melatonin itself causes weight gain—again, the hormone is a well-being multi-hyphenate with a lion’s share of benefits. But if you do take supplements to get your sleep rhythm back on track, you might not want to take them right after eating; once your body enters rest and recovery mode, functions like digestion are put on the back-burner.