6 Signs You're Taking Too Much Melatonin, According To Experts

Whether you have insomnia or are just up late rehashing an embarrassing moment from middle school, there are plenty of reasons that it can be hard to log some quality ZZZs. That’s why many people turn to melatonin supplements to help them get better sleep — particularly during the pandemic, which saw a spike in melatonin sales. While many swear by it, there are side effects of melatonin to be aware of as you give the sleep aid a go.

Melatonin isn’t just a buzzy supplement — it’s actually a hormone that your body creates, says Dr. Dave Rabin, M.D., Ph.D., a psychiatrist, neuroscientist, and co-founder of Apollo Neuro stress relief bands. Your brain naturally releases melatonin when the sun sets to make you drowsy, he explains, then your melatonin level decreases as the sun rises so you can wake up and start your day. Melatonin supplements are just external sources of that same hormone.

To be safe, Rabin recommends taking a low dose (.5 to 1.5 mg) about 30 to 90 minutes before going to bed to most effectively mimic your natural sleep cycle. But pounding gummies or supplements before bed on days you think you need an extra boost is not the key to better sleep, he cautions: Taking too much melatonin can potentially cause more problems than it solves. Below, health experts explain six common side effects of melatonin that you might experience if you’re overloading on the supplement.

1. Headache

Though the side effects of overdosing on melatonin are typically mild, they can still be unpleasant. One of the most common consequences? Headaches, says Lisa Moskovitz, R.D., a registered nurse and dietitian. Taking too much melatonin can give you the opposite effect and disturb normal sleep functions as you’re dealing with a throbbing noggin.

Sometimes you don’t need to overdose to feel these effects — you may just be extra sensitive to the supplement and start feeling it even after an appropriately low dose, she says. If that’s the case, it might be wise to ditch the supplement or find a non-melatonin alternative.

2. Dizziness

Taking too much melatonin can also cause dizziness, says Moskovitz. That’s because your body is trying to get a normal night’s sleep while it’s overloaded with the hormone, which can make you feel, well, not normal.

3. Grogginess

If you take too much melatonin, you might wake up the next morning with some of it still in your body, says Rabin. This can leave you feeling groggy despite getting a full night of sleep.

Timing matters, too. Melatonin instructs your body that it’s time to go to bed, but doesn’t actually put you to sleep, says Moskovitz. So if your insomnia has you up until 3 a.m., taking melatonin in the wee hours of the morning isn’t going to zonk you out — it’s going to incorrectly signal your body that bedtime is approaching, which can throw your sleep cycle out of whack. The fix? Take a lower dose of melatonin before bedtime instead of the moment you want to fall asleep, says Rabin.

4. Nausea

Though it’s less common than the above side effects, taking too much melatonin can sometimes cause an upset or queasy stomach, says Moskovitz. Think hangover, but from your nighttime gummies. Try lowering your dose or taking it less frequently to go easier on your system, she suggests.

5. Interact With Medications

If you’re using melatonin properly but still feel unpleasant afterwards, it might be because the supplement is interacting poorly with medication that you’re taking, says Moskovitz. Melatonin may inhibit the effects of medications you take for blood pressure, seizures, diabetes, or blood clotting. And combining melatonin with central nervous system drugs or contraceptives may increase its sedative effect, thereby upping the odds that you’ll experience some side effects. To be extra cautious, check in with your doctor before trying melatonin to make sure it’s safe for you and any medications you’re taking.

6. Mood Changes

Experiencing these unpleasant side effects can make you feel anxious or irritable (if you wake up feeling groggy, for instance). And, separately, flooding your body with too much of the sleep hormone can disrupt your natural circadian rhythm, which research shows can mess with your ability to regulate your mood and stress hormone levels. Though melatonin-induced mood changes aren’t too significant and should resolve on their own if you lower your dose, extreme or long-term mood changes could be a sign of a larger problem like an underlying mood or sleep disorder. “If you notice significant changes in mood, energy, or anything at all, stop taking it and talk to your doctor,” Moskovitz tells Bustle.

Studies referenced:

Anderson, L. (2016). The Safety of Melatonin in Humans. Clinical Drug Investigation, https://pubmed.ncbi.nlm.nih.gov/26692007/

Costello, R. (2014). The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature. Nutrition Journal, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4273450/

Lusardi, P. (2000). Cardiovascular effects of melatonin in hypertensive patients well controlled by nifedipine: a 24-hour study. British Journal of Clinical Pharmacology, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2014953/

Savage, R. (2020). Melatonin. StatPearls, https://www.ncbi.nlm.nih.gov/books/NBK534823/

Walker, W. (2020). Circadian rhythm disruption and mental health. Nature, https://www.nature.com/articles/s41398-020-0694-0

Experts:

Lisa Moskovitz, R.D., CDN, a nurse and dietitian

Dr. Dave Rabin, M.D., Ph.D., a psychiatrist, neuroscientist, and co-founder of Apollo Neuro