Here's What Happens When You Take Too Much Melatonin

Melatonin is a hormone that your body naturally produces in response to darkness. It's vital in helping regulate your body's internal clock and is regularly studied in connection with insomnia and other sleep disorders (via Brain Disorders & Therapy). While you might think of it as a harmless supplement, or the key to a sound night's sleep, there's more you should know about the hormone. Taking a safe dose as a nightly oral supplement can help to regulate your circadian rhythms and improve your sleep, anxiety, and even heartburn — but taking too much can cause some serious problems.

While there is no one standard dose of melatonin that will work for everybody, a good place to start is between 0.2 and 5 milligrams, depending on your size. From there, you can slowly increase the dose until it has the desired effect (via Healthline). In general, you want to avoid going above 10 milligrams — and definitely not upwards of 30 milligrams, which is believed to be a harmful dose.

Too much melatonin actually can keep you awake

It's important to consult a doctor before adding a melatonin supplement to your routine. You also want to check with them before increasing your dose, since taking too much can have a plethora of unwanted side effects. Failing to do this and jumping straight to a high dose can, in some cases, have the opposite of the desired effect and actually cause you to feel more awake as you lay in bed, trying to fall asleep (via Medical News Today). 

In other cases, taking too much melatonin can cause headaches, nausea, dizziness, irritability, stomach cramps, diarrhea, and anxiety (via Everyday Health). And for some, a high dose of melatonin can affect blood pressure, causing it to dip (via Healthline). And there are more severe symptoms you should be on the lookout for: If you experience extremely high blood pressure, shortness of breath, or sudden chest pain, be sure to seek medical help.