N-Acetyl Cysteine (NAC) for Mood, Immunity, and More

It’s no secret that balancing oxidative stress is vital to a healthy brain and body, but how do you know which antioxidant to choose? N-Acetyl Cysteine (NAC) is growing in popularity not only due to its antioxidant activity but for a host of other benefits that researchers are uncovering.

In this article, we’ll explore what NAC is, how it can support your mind and body, and answer some frequently asked questions about this amino acid.

Health Benefits of NAC

N-acetyl cysteine (NAC) is a precursor to the amino acid L-cysteine. L-cysteine is found naturally in the human body but is regarded as semi-essential as you can end up with insufficient quantities if you don’t get enough of it in your diet or if you’ve been dealing with immune-related issues.

NAC can be found in supplement form and is becoming increasingly popular for its role as an antioxidant. There are a number of potential health benefits associated with NAC supplementation, but the most well researched include:

  • Glutathione production
  • Cognitive benefits
  • Mood support
  • Detoxification
  • Respiratory conditions
  • Immunity

NAC May Enhance Glutathione Production

One of the most well-known benefits of NAC is its role in boosting the antioxidant glutathione. Glutathione is a tripeptide (three amino acids linked together) and is composed of cysteine, glycine, and glutamic acid.

Of the many biological antioxidants, glutathione is considered one of the most important. This powerful nutrient can gather various types of free radicals throughout your body, which may protect your cells from oxidative stress. In addition, glutathione may also support the regeneration of other antioxidant compounds such as vitamin C and vitamin E.

What’s more, glutathione helps support your detoxification pathways and boosts mitochondrial health, making it essential for maintaining the health and function of your cells.[1]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4684116/

NAC and Cognitive Health

NAC has been the subject of research in neurological conditions to boost glutathione production and regulate the neurotransmitter glutamate.

Glutamate is largely considered one of the most vital neurotransmitters due to its role in excitatory neurotransmission (the firing of neurons). It’s estimated that over half of your brain synapses release glutamate. When in balance, glutamate plays a role in learning, memory, and behavior. However, this neurotransmitter can become toxic, creating “excitotoxicity” in cells when it’s overexpressed.[2]https://www.ncbi.nlm.nih.gov/books/NBK10807/

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Alzheimer’s disease is marked by several different neurological imbalances, including inflammation, oxidative stress, excitotoxicity, and mitochondrial dysfunction. By regulating glutamate (and therefore combating excitotoxicity), while also upregulating glutathione (combating oxidative damage and enhancing mitochondrial health), research suggests that NAC may protect against this rampant neurological disease.[3]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5241507/

In animal studies, researchers found that NAC administration slowed cognitive decline and memory loss by stabilizing energy production and uptake in brain cells.[4]https://pubmed.ncbi.nlm.nih.gov/27087133/

In Parkinson’s disease, a neurological disorder marked by low levels of dopamine and high oxidative stress, animal studies have shown that NAC may support brain health in a handful of ways, including:[5]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5241507/

  • Reducing oxidative damage
  • Protecting against dopamine-induced cell death
  • Boosting mitochondrial activity
  • Increasing glutathione antioxidant activity
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NAC May Help with Symptoms of Depression And other Psychiatric Disorders

As a modulator of glutamate and glutathione, NAC may also impact depressed mood and other psychiatric disorders.

Many psychiatric disorders are suspected to originate from inflammation and oxidative stress in the brain. Research shows that NAC may have an antidepressant-like effect due to its ability to mitigate oxidative damage and promote healthy brain cells.[6]https://pubmed.ncbi.nlm.nih.gov/18797252/

In a systematic review and meta-analysis, investigators found a strong correlation with NAC supplementation and the amelioration of depressive symptoms in major depressive disorder (MDD) as well as bipolar disorder.[7]https://pubmed.ncbi.nlm.nih.gov/27137430/

Obsessive-compulsive disorder (OCD) is marked by high levels of glutamate activity in the brain accompanied by oxidative stress. When researchers assessed NAC’s role in augmenting OCD behavior, they found that 2000 mg of NAC daily was more effective than the SSRI drug Fluvoxamine.[8]https://pubmed.ncbi.nlm.nih.gov/26931055/

Due to its role in combating inflammation, promoting mitochondrial health, enhancing antioxidant activity, and blunting glutamate activity, research suggests that NAC may also show positive effects on addictive behavior, anxiety, and schizophrenia.[9]https://pubmed.ncbi.nlm.nih.gov/29876880/[10]https://pubmed.ncbi.nlm.nih.gov/23369637/[11]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3044191/

NAC and Detoxification

NAC may contribute to your detoxification processes by way of glutathione production. Glutathione not only helps protect your cells against toxic compounds, but it also supports the detoxification of both externally and internally produced toxic compounds.

Detoxification in your liver takes place in two phases. In phase one, your liver converts toxins into less harmful intermediates. In phase two, these intermediates are conjugated and made water-soluble so that they can be excreted.

One of the side effects of phase one is the generation of oxidative stress. Here, glutathione comes in as an antioxidant to combat the oxidative damage caused by these reactions. In phase two, glutathione assists in the transport of toxins, facilitating the excretion of toxins from your cells and tissues.[12]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4684116/

Heavy metals are particularly damaging to your body as they deplete glutathione stores and contribute to oxidative damage. Therefore, supplementing with glutathione when heavy metals are present becomes even more vital for healthy detoxification.[13]https://pubmed.ncbi.nlm.nih.gov/9727078/

May Improve Respiratory Conditions

Respiratory conditions such as COPD (chronic obstructive pulmonary disease), bronchitis, and asthma are marked by high levels of inflammation and oxidative stress in your airways.

In COPD, people experience airway constriction due to inflamed mucous membranes often accompanied by excessive mucus production. This can result in difficulty breathing, persistent cough, wheezing, and phlegm that doesn’t subside.[14]https://www.nhs.uk/conditions/chronic-obstructive-pulmonary-disease-copd/symptoms/

If the oxidation and inflammation caused by COPD and bronchitis go untreated, it can cause irreversible damage to the airways. Research shows that NAC may help to mitigate some of this damage, reducing symptoms, slowing the progression, and calming some of the exacerbations.[15]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2706612/[16]https://erj.ersjournals.com/content/16/2/253.short

By decreasing inflammation in the airways, NAC may also improve asthma symptoms, which is a condition marked by difficulty breathing due to narrowing of airways from inflammation and excess mucus.[17]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7487305/

May Help Stabilize Blood Sugar

Issues with blood sugar are intimately related to metabolic diseases and inflammatory processes in your body. While the foods you eat can certainly impact blood sugar, inflammation can also create conditions in your body that make it hard for your cells to receive insulin, the hormone involved in blood sugar regulation.

When inflammation and oxidative stress in your body get out of control, this damage can impact the signaling pathways that regulate insulin and results in insulin resistance.[18]https://pubmed.ncbi.nlm.nih.gov/15998259/

Research in animals shows that NAC’s antioxidant and anti-inflammatory activity can inhibit some of this damage and preserve glucose stability. In other words, NAC helped keep cells and signaling pathways healthy so that blood sugar could be properly removed from the blood and transported into cells where it belongs.[19]https://pubmed.ncbi.nlm.nih.gov/19328229/

NAC May Support Immunity

Glutathione plays a crucial role in immunity, with even small changes in glutathione status creating profound effects on your immune system.

As an antioxidant, glutathione impacts several cellular mechanisms of your immune system, including lymphocytes and natural killer cells.[20]https://pubmed.ncbi.nlm.nih.gov/11115795/

Research into HIV shows that this virus depletes glutathione, and when repleted with NAC supplementation, it normalizes levels of this vital antioxidant and may even suppress replication of the virus.[21]https://pubmed.ncbi.nlm.nih.gov/26597719/[22]https://pubmed.ncbi.nlm.nih.gov/1418777/

Other research supports NAC’s ability to suppress viral replication and inflammatory processes related to the flu virus.[23]https://pubmed.ncbi.nlm.nih.gov/19732754/

NAC Supplement Side Effects

NAC can be found as both a supplement and a medication. As a medication, it is generally used to treat acetaminophen overdose (Tylenol) and can be given in high doses. In this case, some side effects have been noted, including:[24]https://pubmed.ncbi.nlm.nih.gov/19280424/

  • Nausea
  • Vomiting
  • Diarrhea
  • Swelling
  • Low blood pressure
  • Skin itching or rash

NAC may also slow blood clotting, so people with bleeding disorders or on medication should be careful with this supplement.[25]https://pubmed.ncbi.nlm.nih.gov/16607076/


When should you take NAC?

You can take NAC on an empty stomach in the morning or at night. Some people say that supplementing with n-acetyl cysteine makes them sleepy, but that is typically only at high doses and is not the case for everyone.

What does NAC do in your brain?

NAC is a precursor to glutathione and mitigates glutamate activity in your brain. As such, it acts as a powerful antioxidant and also helps to calm excitability in your brain. Research shows it may be helpful for psychiatric disorders as well as neurological diseases like Parkinson’s disease and Alzheimer’s.

What medications does NAC interact with?

If you’re taking medication, it’s always important to run new supplements by your prescribing doctor or pharmacist. NAC (N-acetyl cysteine) may interact with blood thinners or blood pressure medications like nitroglycerin or Warfarin. Therefore, check with your prescribing physician before starting on NAC supplements.

What’s the difference between NAC and glutathione?

NAC (n-acetyl cysteine) is a precursor to glutathione. While they both act as antioxidants in your body, glutathione is made up of three amino acids; cysteine, glycine, and glutamic acid. NAC also directly impacts the neurotransmitters glutamate, while glutathione acts primarily as an antioxidant.

Can you get NAC in your diet?

N-acetyl cysteine (NAC) is a supplement form of cysteine, which is an amino acid. You can get cysteine directly through high-protein foods such as pork, beef, turkey, chicken, fish, lentils, eggs, low-fat yogurt, sunflower seeds, cheese, and some lower protein sources like brussels sprouts and oats.

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