Is your brain fog caused by this simple deficiency ?

Glutathione, brain fog and oxidative stress.

Glutathione and Brain Fog: A Hidden Connection

Brain fog is not a medical diagnosis, yet it is one of the most commonly reported cognitive complaints in today’s world. It is that frustrating feeling of mental cloudiness, where focus, memory, and mental energy seem dulled. I experienced it myself a few years ago, when I was writing my master thesis. There were times when I could not even read a page of a simple document without having to pause. I had to take notes on a piece of paper just to keep track of ideas in the text. Then started my complex and long health journey. I discovered the basics of biochemistry, brain problems, etc. I noticed that the brain fog was way worse when I ate certain foods, or certain beverages. Then, I started to do my homework.

Many people describe it as a state of being “not fully present,” where thoughts feel slow, unclear, or heavy. While it can be triggered by lack of sleep, poor diet, or chronic stress, emerging evidence suggests that biochemical imbalances inside the brain itself may play a key role. Among them, glutathione has gained increasing attention as a crucial molecule in the fight against mental fatigue. As I mentioned previously, brain fog is not a real medical diagnostic, as are parkinson’s disease, GAD, OCD, or other things. But it does not means that it does not exist.

Glutathione is a small molecule composed of three amino acids: glutamine, cysteine, and glycine. It is found in every cell of the body, but the brain depends on it in unique and vital ways. Often referred to as the body's “master antioxidant,” glutathione plays a central role in neutralizing harmful free radicals, maintaining mitochondrial function, detoxifying toxins and heavy metals, and supporting overall brain health. Its levels directly influence how well the brain handles stress, inflammation, and toxic exposure.

The brain is an incredibly metabolically active organ. Despite accounting for only about two percent of body weight, it uses up nearly twenty percent of the body's oxygen. This high oxygen use inevitably results in the generation of free radicals—unstable molecules that can damage cells if not neutralized. The natural solution to this oxidative threat is the antioxidant system, with glutathione as its key defender. When glutathione levels are adequate, they protect neurons from oxidative damage and inflammation. But when levels drop, the brain becomes more vulnerable, potentially resulting in symptoms that look and feel like brain fog. I have to say that my thousands of hours on reddit forums and Facebook groups have convinced me that what people called “brain fog” was often associated with low-glutathione.

Low glutathione levels have been linked to various neurological conditions, including Alzheimer's disease, Parkinson’s disease, multiple sclerosis, chronic fatigue syndrome, and even depression. Many of these disorders include brain fog as a symptom, suggesting a common biochemical thread. Even outside of clinical diagnoses, people under chronic stress or those exposed to environmental toxins often show depleted glutathione and report cognitive issues. This does not limit to the brain but to the whole body.

Here is an example of Glutathione supplement, under the form of NAC (Junipers supplements, from the UK).

One of the reasons glutathione is so crucial is its role in regulating the brain’s detoxification system. The brain is highly sensitive to toxins, such as heavy metals and chemical pollutants. These substances can accumulate and interfere with neurotransmitter function, energy production, and neuronal signaling. Glutathione acts like a cellular sponge, binding to toxins and facilitating their removal. When levels are low, this system becomes sluggish, allowing toxic build-up that can manifest as mental fogginess and fatigue.

Additionally, glutathione protects mitochondria, the energy-producing organelles within cells. Healthy mitochondrial function is essential for mental clarity and sustained cognitive performance. When mitochondria are damaged by oxidative stress and not protected by glutathione, they produce less energy and generate more free radicals in a vicious cycle. This mitochondrial dysfunction has been observed in people with persistent brain fog, particularly those recovering from viral illnesses or chronic fatigue conditions.

Modern lifestyles can significantly deplete glutathione levels. Chronic psychological stress, poor nutrition, sleep deprivation, exposure to air pollution, alcohol consumption, and certain medications all place a burden on the body’s antioxidant system. Over time, these factors can exceed the body’s ability to regenerate glutathione, especially if the diet lacks the necessary building blocks such as sulfur-containing amino acids. As a result, the brain is left more exposed to oxidative damage and inflammation.

Brain fog is ultimately a sign that the brain’s internal balance has been disrupted. While it can have multiple causes, glutathione appears to be a central player in restoring clarity and resilience. Some people report noticeable improvements in focus and mental energy after taking steps to support glutathione production. This is particularly true when the fogginess is accompanied by fatigue, chemical sensitivity, or sluggish detoxification.

To support healthy glutathione levels, the body requires adequate intake of certain nutrients. Cysteine, in particular, is a rate-limiting amino acid in glutathione synthesis. One of the most effective ways to boost cysteine and therefore glutathione is through supplementation with N-acetylcysteine (NAC), which has been extensively studied for its neuroprotective and antioxidant properties. NAC has shown promise in mental health, especially in conditions characterized by oxidative stress and inflammation.

Another important compound is alpha-lipoic acid, a naturally occurring antioxidant that helps regenerate both glutathione and other antioxidants like vitamin C and E. Alpha-lipoic acid crosses the blood-brain barrier and supports mitochondrial function, making it especially helpful for brain health. In addition to supplements, consuming sulfur-rich foods such as garlic, onions, and cruciferous vegetables like broccoli and Brussels sprouts can support natural glutathione production.

Good-quality whey protein is another source of cysteine and can be particularly useful for those who are physically active or under stress. Regular physical exercise has also been shown to boost endogenous glutathione levels, as has adequate, restorative sleep. Sleep plays a vital role in the brain’s detoxification process, particularly through the glymphatic system, which is most active during deep sleep stages.

NAC and glutathione are used for many inflammatory conditions, such as COVID and other SARS related diseases. To take a recent and major example.

Reducing toxic exposures is equally important. This includes avoiding processed foods, minimizing alcohol intake, and limiting exposure to heavy metals and household chemicals when possible. In some cases, direct supplementation with liposomal or acetyl-glutathione may be beneficial, especially for individuals with poor absorption or chronic health conditions that impair detoxification.

While glutathione alone is not a magic bullet, its role in brain function is undeniable. It supports detoxification, reduces inflammation, protects neurons, and sustains cellular energy—all of which are essential to clear, focused thinking. Brain fog can stem from many sources, including hormonal changes, gut-brain imbalance, blood sugar fluctuations, or mental overload. Yet, the one thing all these causes share is an increased need for antioxidant defense and cellular repair.

Supporting glutathione production is not just about eliminating fog; it’s about building long-term cognitive resilience. By strengthening your internal defenses, you help your brain handle modern stressors with greater ease and clarity. For people suffering from persistent brain fog, testing glutathione levels or trying a glutathione support protocol may offer insight and relief.

The most serious work on NAC and glutathione has been conducted by a famous psychiatric researcher, Michael Berk, from Australia. I really encourage people interested in the subject to take a look at what this doctor did. He specifically worked on bipolar disorder, schizophrenia and depression. OCD is another indication for which people can find NAC to be successful. I particularly think of people who suffer from intrusive thoughts and tics (hair pulling, compulsive eatings, etc).

In conclusion, glutathione is more than just an antioxidant. It is a guardian of mental clarity, a cellular detoxifier, and a key player in the body’s ongoing battle against cognitive stress. While it may not be the only cause of brain fog, its depletion is a powerful and often overlooked contributor. Rebuilding it naturally through nutrition, lifestyle, and targeted supplementation can be a game-changer for cognitive function.

Brain fog is a message. And sometimes, that message is: your cells need help. Supporting glutathione may be one of the most important steps you can take to clear the fog and reclaim your mental sharpness. If I were honest with you (I am), I would tell you that NAC is one of the most important supplement that I take. Since I had very bad brain fog in 2020-2021, I decided it incorporate it in my daily routine. Never without NAC again.

Dosage and indications :

• NAC (N-acetyl-Cysteine) : this is the direct precursor to Glutathione in the body. Effective dosages are from 600 to 3200mg / day

• Glutathione (reduced form)

  The word “reduced” should not lead you to think that it is less effective. It simply means that it is directly active within your body.

  From 500 to 2000mg a day

Food sources :

As for any products, glutathione is usually better absorbed when taken through food. Some food are extremely rich in glutathione. Here are some of them :

Asparagus

Avocados

Spinach

Okra

Zucchini

Cucumber

Tomatoes

Side effects :

In some people, NAC can cause abdominal cramps and bloating, but the side effects are usually very mild and benign. There are some reports of worsening anhedonia when people supplement with NAC and glutathione.

Complete sources :

• Bradlow, R. C. J., Berk, M., Kalivas, P. W., Back, S. E., & Kanaan, R. A. (2022). The Potential of N-Acetyl-L-Cysteine (NAC) in the Treatment of Psychiatric Disorders. CNS Drugs, 36(5), 451–482.
  Link

• Khoja, E. (2024). N-Acetyl Cysteine: A Potential Adjunctive Therapy in Neuropsychiatric Disorders. Journal of Experimental Biology and Medical Science.
  Link

• Berk, M., Malhi, G. S., Gray, L. J., & Dean, O. M. (2013). The promise of N-acetylcysteine in neuropsychiatry. Trends in Pharmacological Sciences, 34(3), 167–177.
  Link

• Dean, O., Giorlando, F., & Berk, M. (2011). N-acetylcysteine in psychiatry: current therapeutic evidence and potential mechanisms of action. Journal of Psychiatry & Neuroscience, 36(2), 78–86.
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• Ghiam, M. K., et al. (2021). Drug Repurposing in the Treatment of Traumatic Brain Injury. Frontiers in Neuroscience, 15, 635483.
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• Fesharaki-Zadeh, A., Arnsten, A. F. T., & Wang, M. (2023). Scientific Rationale for the Treatment of Cognitive Deficits from Long COVID. Neurology International, 15(2), 725–742.
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• Yale Medicine. (2022, December 12). Long COVID Brain Fog Treatment Shows Improvement With Two Drugs.
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• Soheilipour, A. (2025). Investigating the Effect of N-Acetyl Cysteine on Positive and Cognitive Symptoms of Schizophrenia. Iranian Journal of Psychiatry and Behavioral Sciences.
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• Smaga, I. (2021). N-acetylcysteine as a new prominent approach for treating psychiatric and neurological disorders. British Journal of Pharmacology.
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• Chakraborty, S. (2025). The neuroprotective effects of N-acetylcysteine in psychiatric and neurological disorders. Neuropharmacology.
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• Aslanlar, D. A., et al. (2024). N-acetylcysteine ameliorates chemotherapy-induced anxiety and depression-like behaviors. Neuroscience Letters.
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• Sinha, S. (2024). N-acetylcysteine (NAC): impact on psychiatric disorders. Advances in Human Biology.
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• Ooi, S. L., Green, R., & Pak, S. C. (2018). N-Acetylcysteine for the Treatment of Psychiatric Disorders: A Review of Current Evidence. BioMed Research International, 2018, 2469486.
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• Ooi, S. L., et al. (2018). N-Acetylcysteine for the Treatment of Psychiatric Disorders. BioMed Research International.
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• Wikipedia. Acetylcysteine.
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• Berk, M., et al. (2019). Mitochondrial agents, N-acetylcysteine, and placebo in bipolar depression. BMC Medicine, 17, 18.
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• Hardan, A. Y., et al. (2012). A randomized controlled pilot trial of oral N-acetylcysteine in children with autism. Biological Psychiatry, 71(11), 956–961.
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• McKetin, R., et al. (2017). N-acetylcysteine for methamphetamine dependence: A randomized controlled trial. Drug and Alcohol Review, 36(2), 153–159.
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• Arteaga-Henríquez, G., et al. (2023). Immunoregulatory agents in autism spectrum disorder. CNS Drugs, 37(3), 215–229.
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• Pangrazzi, L., et al. (2024). N-acetylcysteine counteracts immune dysfunction and autism-related behaviors in Shank3b−/− mice. Antioxidants, 13(6), 1390.
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• Ghanizadeh, A., & Derakhshan, N. (2012). N-acetylcysteine for treatment of autism, a case report. Journal of Research in Medical Sciences, 17(10), 985–987.
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• Raghu, G., et al. (2021). The multifaceted therapeutic role of NAC in disorders characterized by oxidative stress. Current Neuropharmacology, 19(8), 1202–1224.
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• Slattery, J., Kumar, N., & Delhey, L. (2015). Clinical trials of N-acetylcysteine in psychiatry and neurology: A systematic review. Neuroscience & Biobehavioral Reviews, 55, 294–321.
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