“Brain fog” is not a medical condition but a group of symptoms like memory trouble, lack of focus, fatigue, and scattered thoughts. Low nutrient levels can be a cause, so taking supplements may be beneficial.

It commonly affects people with certain medical conditions, including fibromyalgia, Hashimoto’s thyroiditis, chronic fatigue syndrome, depression, autism spectrum disorder, celiac disease, and neuropsychiatric disorders (1, 2, 3).

Many factors, including nutrient deficiencies or inadequacies, may contribute to brain fog symptoms. These are more common in people with medical conditions commonly associated with brain fog (4, 5, 6).

This article covers 6 evidence-based supplements that may help with brain fog.

Share on Pinterest
Westend61/Getty Images

Vitamin D is a fat-soluble nutrient necessary for immune system function, brain health, and more.

Having low or deficient vitamin D levels may negatively impact cognitive health and contribute to brain fog symptoms.

People who have depression or depressive symptoms often experience brain fog symptoms such as poor concentration and memory problems.

People with depression are also more likely to have deficiencies in several nutrients, including vitamin D (7, 8).

Vitamin D deficiency is associated with an increased risk of depressive symptoms. Research suggests that vitamin D supplements can help increase vitamin D levels and may help improve depressive symptoms, including brain fog (9, 10, 11, 12, 13).

Other studies show that vitamin D supplementation may improve overall mental health — including mood, negative thoughts, and symptoms of anxiety and depression — in certain people (14, 15).

This suggests that supplementing with vitamin D may alleviate brain fog, at least to some extent.

Also, a small study in 42 postmenopausal women who were low in vitamin D found that those who supplemented with 2,000 IU of vitamin D per day for 1 year performed better in learning and memory tests than those who took 600-IU or 4,000-IU doses (16).

However, more research is needed.


Some studies show that low vitamin D levels may be linked to brain fog symptoms. Supplementation may help improve memory, concentration, and mood in some people, which may help alleviate brain fog.

Omega-3 fatty acids are well known for their impressive health effects. Taking concentrated omega-3 supplements may benefit brain health and improve certain symptoms of brain fog, including difficulties with attention and memory (17).

Studies show that supplementing with the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) may support brain health, including memory, attention, and mood.

A study including 176 adults with low omega-3 intake found that supplementing with 1.16 grams of DHA per day for 6 months led to improvements in episodic and working memory compared with a placebo (18).

Another study found that treatment with 1.25 grams or 2.5 grams of omega-3 fatty acids per day reduced memory decline in people experiencing loneliness over a 4-month period (19).

Omega-3 supplements may also improve depressive symptoms and boost mood, which may help reduce symptoms of brain fog.

One review of 26 studies suggested that taking omega-3 supplements with EPA concentrations of at least 60% at a dosage of at least 1 gram per day may help treat depressive symptoms (20).

What’s more, omega-3 supplements may help improve anxiety symptoms. People who experience anxiety may report symptoms of brain fog because anxiety can negatively affect mood, concentration, and memory (21, 22).


Some research suggests that omega-3 supplements may improve some aspects of cognitive health and therefore help reduce symptoms of brain fog.

Magnesium is an essential mineral that’s concentrated in foods like beans, seeds, and spinach. It’s necessary for many essential body functions, such as enzymatic reactions, energy production, nerve function, and blood pressure regulation (23).

Many people don’t get enough magnesium in their diet, which may negatively impact brain health and lead to brain fog symptoms such as difficulty concentrating.

Low magnesium levels are common in those who are stressed and can even increase susceptibility to stress (24).

Stress can cause memory impairment, poor concentration, and anxiety symptoms (25, 26).

For this reason, maintaining optimal magnesium levels through supplementation may help reduce susceptibility to stress and therefore improve stress-related cognitive impairment and brain fog symptoms.

Plus, some studies have linked suboptimal magnesium levels with reduced cognitive function and reaction time as well as increased risk of cognitive impairment (27, 28).

A study in 2,466 people ages 60 and up found that those with higher magnesium levels did better on tests of cognitive functions like attention and memory and had lower risks of developing cognitive impairment than those with lower magnesium levels (29, 30).

Some research suggests that magnesium supplements may also help treat symptoms of anxiety and depression, which may improve symptoms of brain fog related to these common mental health conditions (31).


Having low magnesium levels may negatively affect brain health. Supplementing with magnesium may help reduce certain symptoms of brain fog.

Vitamin C is well known for its role in immune health, but this nutrient also supports many other important functions in the body, including brain health.

A study that included 80 healthy adults found that those with adequate blood levels of vitamin C performed significantly better in tests assessing memory, attention, reaction time, and focus than those with low vitamin C levels (32).

Low vitamin C levels may also negatively affect mood, and vitamin C deficiency is linked to depression and cognitive impairment (33).

A study in 139 young men found that higher vitamin C levels were associated with improved mood and lower rates of depression and confusion (34).

What’s more, a recent study suggests that vitamin C supplementation may improve mood in people with subclinical depression, which could enhance cognitive performance, thus reducing depression-related brain fog (35).


Maintaining adequate vitamin C levels by supplementing with vitamin C may help maintain brain health and improve brain fog symptoms.

Studies show that low or deficient levels of certain B vitamins can lead to symptoms of brain fog such as memory problems, difficulty concentrating, and more.

In people with low levels of B vitamins, supplements may help reduce these symptoms.

For example, a study in 202 people with cognitive impairment and low or deficient B12 levels found that B12 supplementation led to improved cognition in 84% of participants and improved scores on memory and attention tests in 78% of participants (36).

A recent study that included 39,000 people found that low vitamin B12 levels were associated with poorer attention and memory (37).

Having low or deficient levels of other B vitamins, including vitamin B6 and folate, may also worsen symptoms of brain fog, including difficulties with concentration and memory (38, 39).

For this reason, taking a high quality B complex supplement may help reduce the risk of these brain fog symptoms.


Low levels of certain B vitamins may worsen symptoms of brain fog. For this reason, taking a B complex supplement may help reduce brain fog symptoms in some people.

L-theanine is a compound that’s concentrated in green tea and other plants.

Some studies suggest that taking an L-theanine supplement may help improve mental alertness, reaction time, and memory.

A recent study in 69 adults ages 50–69 found that a single dose of 100.6 mg of L-theanine improved reaction time and working memory on cognitive tests (40).

L-theanine supplements may also reduce tension and enhance calmness and relaxation (41).

What’s more, a small study found that 200 mg of L-theanine per day helped reduce stress-related symptoms and improve sleep and certain aspects of cognitive health compared with a placebo (42).

Reducing stress, improving sleep quality, and supporting cognitive health may all help relieve brain fog.


L-theanine may reduce brain fog symptoms such as memory problems and delayed reaction time when taken as a supplement. It may also help reduce stress and improve sleep, which may relieve brain fog symptoms.

Brain fog symptoms can be related to a number of factors, including nutrient deficiencies, lack of sleep, stress, and even undiagnosed medical issues.

If you’re experiencing symptoms such as memory problems, difficulty concentrating, and inability to process information, it’s a good idea to talk with a healthcare professional.

They can run tests that may help you find out why you’re experiencing these symptoms.

For example, medical conditions such as Hashimoto’s thyroiditis, celiac disease, and anxiety disorders may present with brain fog symptoms (1, 3, 43).

Plus, dementia and Alzheimer’s disease can present with brain fog symptoms such as forgetfulness and difficulty processing information.

It’s critical to get the proper diagnosis and treatment if an underlying medical condition is contributing to brain fog symptoms.

Some lifestyle habits can also lead to brain fog symptoms.

Lack of sleep, a diet high in ultra-processed foods, and excessive alcohol intake have all been linked to poor memory, difficulty concentrating, depressive symptoms, and other cognitive issues that some people may describe as brain fog (44, 45, 46).

Multiple factors may be contributing to your brain fog, so it’s important to work with a medical professional to get to the bottom of why you’re experiencing these symptoms and create a treatment plan.


Many factors, such as nutrient deficiencies, medical issues, and sleep deprivation, may contribute to brain fog. If you have brain fog, speak with a healthcare professional to rule out serious potential causes and find the proper treatment.

“Brain fog” describes cognitive symptoms such as memory problems and difficulty concentrating.

Some research suggests that certain supplements may be helpful for those experiencing brain fog symptoms.

Having suboptimal or low levels of certain nutrients may contribute to or cause brain fog-related symptoms, so supplementation with these nutrients may help.

However, brain fog has many possible causes, some of which are serious. It’s essential to work with a healthcare professional to get proper care.

Just one thing

Try this today: Everyone has an occasional “off” day when their mind isn’t as clear as usual. However, if you’re experiencing significant issues such as daily brain fog, it’s important to discuss your symptoms with a healthcare professional.

Was this helpful?