Exposure to negatively charged ions offers many health benefits. It’s believed negative ion therapy can improve symptoms of depression, but more research is needed to confirm.

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You may have heard of grounding mats and air ionizers that promise to offer relief for depression or provide other health benefits. But do these devices actually work?

Air ionizers and grounding mats attempt to mimic a naturally-occurring phenomena known as “negative ions.” Under certain circumstances, negative ions can accumulate in specific areas like waterfalls and forests.

It’s known that these negative ions do indeed form, but whether or not they’re beneficial for health is not quite certain. Further, it’s not been confirmed that obtaining these ions from man-made devices offers any appreciable benefits.

Negative ion therapy refers to the practice of exposing yourself to negatively charged particles. This can be accomplished naturally through environmental exposure, or artificially by using an ionizing device.

“Particles” refer to the atoms and molecules that make up the space around you. All of the space around you is composed of small molecules like carbon and hydrogen. These molecules ultimately combine in different ways to form either:

  • solid
  • liquid
  • gaseous matter

Air, for example, is composed of molecules like nitrogen and oxygen that are in a gaseous state. When these molecules combine, they form stable, uncharged compounds.

These compounds can assume a negative or positive charge, and are then referred to as “ions.”

Positive vs. negative ions

Molecules can be broken down into atoms consisting of electrons and protons. Electrons have a negative charge, and protons have a positive charge.

When there’s an equal number of electrons and protons in a molecule, it’s considered a neutral or uncharged molecule.

But if a molecule gains an electron through a chemical reaction, for example, then it gains an overall negative charge. Similarly, a molecule that lost some of its electrons gains a positive charge.

It’s believed that exposure to negative ions, either from the air or through contact with a surface, is potentially beneficial for your health. This is the basic premise of negative ion therapy.

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Negative ions occur naturally as a product of environmental reactions or related environmental phenomena. According to 2018 research, natural sources of negative ions can include:

  • sunlight
  • air (especially after a lightning/thunderstorm)
  • waterfalls
  • seashores
  • plants

The above research indicates that exposing yourself to the natural environment in general also exposes you to negative ions. Large natural areas in particular, like a state park or beach, contain large amounts of negative ions, according to 2018 research.

A common practice in Japan known as “forest bathing” is one way of obtaining negative ions, according to 2019 research. Visiting a forest and walking through it would be considered forest bathing.

You may also be exposed to negative ions by using an ionizing device. Common devices include both air ionizers and grounding mats. But the extent to which these actually provide you with negative ions is uncertain.

Generally, the effect of negative ions specifically for depression is a topic that requires more research. Several small studies have demonstrated benefits, but there have been no consistent conclusions or recent research.

A 2013 review of thirty-three studies from 1957 to 2012 showed some benefits for depression following exposure to negative ions. But the data was inconsistent.

Further, it’s uncertain how much exposure would be necessary, and how often, in order to gain any benefits.

More recently, a small 2017 study examined the effect of negative ion exposure in 40 patients with seasonal depression. Positive changes in mood were reported, but were however attributed to the placebo effect.

Aside from depression, negative ion therapy may potentially offer other health benefits. According to 2018 research, some of these benefits may include:

  • inhibition of in microorganism growth
  • decreased blood pressure
  • improved cognitive performance
  • improved overall wellbeing
  • reductions in cancer cell growth
  • reductions in airborne allergens like dust and mold

Negative ion therapy may be beneficial for your health, but there isn’t much objective evidence to support its use. Air ionizers seem to be best at cleaning the air, which can be beneficial for respiratory health, but not necessarily for your mood.

Spending time outdoors in large natural areas seems like the best way to expose yourself to negative ions.

There are known health benefits associated with spending time in nature, and some of these benefits may be due directly to the presence of negative ions.