It may be hard to define a melatonin overdose because no standard or safe dose has been established. However, in large amounts, melatonin supplements may disrupt sleep cycles and cause other acute and chronic symptoms.
While the body naturally produces melatonin, some people may take supplements to aid their sleep cycle and calm down. But taking too much supplementary melatonin can disrupt your circadian rhythm (also called your sleep-wake cycle). It may also cause other unwanted side effects.
You can technically overdose on melatonin, which means you take more melatonin than your body can handle at once. However, there isn’t an official or standard safe melatonin dosage that applies to everyone. How much you need may depend on your requirements, age, height and weight, and other important factors.
Some people are also more sensitive than others to the effects of melatonin. A dose that might cause side effects in one person may have little effect on someone else.
The standard dose for adults ranges between 1 and 10 mg. Some healthcare professionals believe doses of 30 mg may be harmful.
A standard or safe dose of melatonin refers to the lowest dose that’s effective in helping you fall asleep without causing side effects. Generally, a dose between 0.2 and 5 mg is considered a safe starting dose.
In general, starting low and moving up slowly and carefully is better if you see encouraging results. If your sleep problems persist, a doctor may help explore the possible causes.
In the end, a safe dose will depend on your body weight, age, and sensitivity to the supplement.
Healthy children under age 3 years should avoid melatonin supplements unless otherwise directed by a doctor. Possible melatonin side effects in children include headaches, drowsiness, dizziness, agitation, and bedwetting.
Too much melatonin can have the opposite effect of its intended purpose. It can make it harder to sleep because your circadian rhythms may get disrupted. “Too much” in this context may vary depending on your size and needs.
An overdose can leave you groggy and sleepy during the day and could also give you nightmares or vivid dreams at night.
Signs that you’ve taken more melatonin than your body can take may include:
- persistent nausea
- unexplained dizziness
- headaches
- irritability
- anxiety
- diarrhea
- sudden joint pain
For some people, too much melatonin can also affect blood pressure. Medications that lower blood pressure, such as calcium channel blockers and beta-blockers, may reduce your body’s natural production of melatonin.
However, taking a supplement to make up for lower melatonin levels may not always be advisable. Only a specialized healthcare professional can determine if you need melatonin and other supplements, or if you are taking medications that may interact with it.
Because melatonin can affect your sleep-wake cycle, it’s important to avoid taking melatonin supplements with alcohol or caffeine. These can interfere with your circadian rhythm and your natural melatonin production.
Before starting melatonin or any over-the-counter (OTC) medication or supplement, it’s essential to talk with a doctor. This is especially true if you take prescription medications or have a chronic condition.
For example, birth control pills may cause your body to produce more melatonin, so taking a supplement could push your levels into an unhealthy range.
Taking melatonin with anticoagulant drugs, such as warfarin (Coumadin), could increase your risk of bleeding.
You should also avoid taking melatonin if you take corticosteroids to suppress your immune response in conditions such as rheumatoid arthritis or lupus.
When to seek medical care
If you think you may have taken too much melatonin at once, call Poison Control at 800-222-1222.
Call 911 and seek emergency help if you experience the following symptoms:
- sudden shortness of breath
- sudden and persistent chest pain
- blood pressure that’s 180/120 mm Hg or higher
- confusion
- dizziness that doesn’t go away
These signs may not always be related to melatonin or an interaction between melatonin and other medications. However, they shouldn’t be ignored, as they can indicate a medical emergency.
Though melatonin can be very helpful for some people needing a little extra help falling and staying asleep, it’s not for everyone. You may not tolerate it well, even at low doses. You may find that it doesn’t help you sleep, regardless of the dose.
Melatonin use is unlikely to cause serious medical problems, but caution is advised. The Food and Drug Administration doesn’t regulate this supplement, so there are no official dosing guidelines to follow and no way of determining its quality. For further questions, a healthcare professional specializing in sleep health or a pharmacist can help.
If insomnia is a problem, talk with a sleep specialist. Other lifestyle changes, such as cutting back on caffeine and alcohol or changing your bedtime routine, may also help.
