I’ve had this issue every time I’ve tried melatonin supplements, at any dose. I lie down and feel like my airways are somewhat constricted, and I have to make a conscious effort to breathe. As you can imagine, this is extremely distressing when you’re trying to fall asleep and causes it to have the opposite of a relaxing effect.

I’ve had other significantly negative side effects from melatonin like jaw grinding and weird dreams, but this is the biggest reason I don’t use it at all anymore. For a long time, I was reluctant to talk about it because almost every doctor I’ve mentioned this to has acted like I was insane.

Now I’ve stumbled across some research that suggests both endogenous melatonin and supplements can cause inflammation of airways and worsen asthma. I don’t have asthma or any other respiratory disorder, but it’s not a stretch to think that it could cause noticeable inflammation in even a healthy person. I’m really curious to see if anyone else here has had breathing difficulties after taking it.