Can Zinc Cause Insomnia? (A Research-Backed Answer)

It’s rare for zinc to cause insomnia.

In fact, research shows that zinc usually helps improve sleep.

I’ll give you a quick overview of what research there is on zinc and sleep, which will hopefully clear your questions up.

Is There Any Way For Zinc To Cause Insomnia?

In healthy people, there is no clinical evidence that I could find linking zinc consumption to sleep issues.

The only realistic way for zinc to cause insomnia is from some weird interaction with another medication or medical condition.

Either way, you’re not going to find an answer to that, or help for it, on the Internet. You’ll need to see a doctor.

Is Insomnia a Symptom of Zinc Toxicity?

Consuming too much zinc can be bad for your health. It’s pretty hard to get without overdoing zinc supplements though.

Common symptoms of zinc toxicity include (1):

• Nausea
• Vomiting
• Loss of appetite
• Abdominal cramps
• Diarrhea
• Headaches

Those symptoms could indirectly cause sleep issues I suppose, but it’s pretty unlikely for someone not to notice them.

For reference, here’s the NIH’s table of the tolerable upper limit for zinc:

Adults should have no more than 40 mg of zinc per day. The RDA is much lower.

SummaryIt is unlikely for zinc intake (at any level) to cause insomnia. There is likely an underlying condition or other explanation for sleep issues in those who are consuming extra zinc.

How Zinc Helps Sleep

Researchers still don’t know the exact mechanisms behind how zinc affects sleep, but there is a decent amount of research that all shows that relatively high zinc levels improve sleep (2):

1. A correlational study found that people sleeping a “normal” amount (7-9 hours) had higher levels of serum zinc (1.337–1.442 mg/L) than short (<7h) or excessively long sleepers (>9 h) (0.789–0.934 mg/L) (3).
2. Zinc supplementation in infants with malnutrition helped infants sleep a total of 1.7 hours extra per day over a 12 month period (4).
3. In patients receiving a combination of melatonin, magnesium, and zinc one hour before bedtime, Pittsburgh Sleep Quality Index scores went from 12.7 to 5.5 (from “poor” to almost “good) (5).
4. In a group of volunteers who ate 40 g of oysters per day (15 mg of zinc) for 12 weeks, sleep efficiency and sleep onset latency both improved compared to the control group (see graph below) (6).

SummaryWhile there isn’t a ton of research looking at the effect of zinc levels and sleep, it all points towards a healthy zinc intake improving sleep.

If Zinc Isn’t Causing Insomnia, What Is?

If I started to take a zinc supplement or eat more foods high in zinc, and started having sleep troubles, my first suspect wouldn’t be zinc.

Instead, I’d be looking for other recent changes in my life:

• New sources of stress - e.g. Moving, money problems, grief, etc.
• Other medications and supplements that I started to take
• Changes to when I’ve been eating
• Changes to other aspects of sleep hygiene

You might also want to review the main risk factors of insomnia to see if anything seems relevant.

If you develop chronic insomnia, see a medical professional.

Nothing in this post should be taken as medical advice, just an overview of what the research says about zinc and insomnia.

References

1. NIH: Zinc Fact Sheet
2. Dietary Zinc Acts as a Sleep Modulator
3. Serum zinc, copper, and zinc/copper in healthy residents of Jinan
4. The effects of iron and/or zinc supplementation on maternal reports of sleep in infants from Nepal and Zanzibar
5. The effect of melatonin, magnesium, and zinc on primary insomnia in long-term care facility residents in Italy: a double-blind, placebo-controlled clinical trial
6. Zinc-rich oysters as well as zinc-yeast- and astaxanthin-enriched food improved sleep efficiency and sleep onset in a randomized controlled trial of healthy individuals