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January 18, 2023 By David Tomen 432 Comments

N-Acetyl L-Cysteine

N-Acetyl L-Cysteine
N-Acetyl L-Cysteine (NAC) is a powerful anti-oxidant, can boost mood, lower anxiety, improve memory, and reduce compulsive behavior

N-Acetyl L-Cysteine (NAC or N-acetylcysteine) is the N-acetyl derivative of the naturally occurring amino acid L-cysteine. And works primarily by helping restore the body’s natural antioxidant glutathione (γ-glutamylcysteinylglycine; GSH).

As the most abundant antioxidant in your body, GSH is responsible for maintaining oxidative balance in each of your cells.

Taking glutathione as a nootropic supplement does not adequately restore GSH levels in your brain because it can’t cross the blood-brain barrier. This vastly underrated nootropic, NAC easily penetrates the blood-brain barrier and raises glutathione levels in your brain.[i]

NAC has been used to treat acetaminophen poisoning for decades.[ii] Every year there are 56,000 ER visits from Tylenol overdose, resulting in at least 100 deaths. [iii] NAC provides the glutathione your liver needs to fight off the metabolite NAPQI in Tylenol that does severe liver damage.

As a nootropic, NAC helps prevent glutamate toxicity, boosts dopamine, and reduces inflammation, oxidative and free radical damage.

Where to buy: one of the only vendors still selling NAC and I highly recommend them: Life Extension – NAC

N-Acetyl L-Cysteine helps:

  • Neuroprotection. NAC as a precursor of glutathione, is a potent antioxidant, anti-inflammatory and free radical scavenger.[iv] Your brain is especially vulnerable to inflammation, free radical and oxidative damage. Affecting cognition, long-term potentiation, memory and mood.
  • Neurotransmitters. NAC modulates glutamate levels and dopamine release in the brain. Excess glutamate in your brain is toxic to brain cells affecting neuron health, cognition, memory and mood. And NAC protects dopamine receptors. Influencing dopamine levels and function in your brain. Even protecting dopaminergic nerve terminals from chronic methamphetamine use.[v]
  • Anxiety and depression. NAC reduces irritability, anxiety and depression. NAC increases your body’s antioxidant capacity, and balances excitatory and inhibitory neurotransmitters in your brain. Resulting in less anxiety and depression.

Table of Contents

  • Overview
  • How does N-Acetyl L-Cysteine work in the Brain?
  • How things go bad
  • N-Acetyl L-Cysteine benefits
  • How does N-Acetyl L-Cysteine feel?
  • N-Acetyl L-Cysteine Clinical Research
    • N-Acetyl L-Cysteine increases dopamine
    • N-Acetyl L-Cysteine repairs Traumatic Brain Injury
    • N-Acetyl L-Cysteine helps alleviate depression
  • N-Acetyl L-Cysteine Recommended Dosage
  • N-Acetyl L-Cysteine Side Effects
  • Where to buy N-Acetyl L-Cysteine
  • Nootropics Expert Recommendation

Overview

N-Acetyl L-Cysteine (NAC) is the N-acetyl form of the naturally occurring amino acid L-Cysteine.

N-Acetyl-L-Cysteine
N-Acetyl L-Cysteine

L-Cysteine is naturally produced in your body using the amino acid methionine. You can also get L-Cysteine from eating ricotta and cottage cheese, yogurt, pork, chicken, turkey, duck, wheat germ, granola and oat flakes.

But acute stress, illness, or a poor diet can deplete L-Cysteine levels in your body and brain. The quickest and most efficient way to boost levels of L-Cysteine is to supplement with N-Acetyl L-Cysteine (NAC).

NAC regulates the amount of glutamate in your brain. Glutamate is a neurotransmitter that is responsible for sending signals between neurons in the brain. This plays an important role in learning and forming memories.

But too much glutamate can be toxic to brain cells. NAC regulates the amount of glutamate and keeps it at safe, healthy levels.

NAC influences the amount of dopamine available in your brain. It works to keep dopamine receptors healthy and able to transmit and receive dopamine. These neurotransmitters are crucial for cognitive energy and drive, motor control, feelings of pleasure, and focus.

NAC is a precursor to the powerful anti-oxidant glutathione (GSH). GSH is a potent anti-inflammatory, anti-oxidant and free radical scavenger.

Your brain is especially vulnerable to inflammation, free radical and oxidative damage. If left unchecked, inflammation, oxidation and free radicals can negatively affect cognition, long-term potentiation, memory and mood.

As a nootropic, NAC can boost glutathione and dopamine levels in your brain. NAC is also used by medical professionals to treat serious cognitive disorders like schizophrenia, bipolar disorder, severe depression and anxiety.

N-Acetyl-L-Cysteine-boosts-brain-derived-neurotrophic-factor

How does N-Acetyl L-Cysteine work in the Brain?

N-Acetyl L-Cysteine boosts brain health and function in several ways. But two in particular stand out.

  1. N-Acetyl L-Cysteine reduces oxidative stress. Oxidative stress results in free radical damage in brain cells. Leading to neurodegeneration and ultimately Alzheimer’s, Parkinson’s and other age-related neuronal disorders. Proteins and DNA are injured, inflammation, tissue damage and cellular apoptosis (cell death) are the result.

And neurohackers are not immune to oxidative stress no matter what your age. Keep this in mind the next time you reach for a Diet Coke. Consumption of the artificial sweetener aspartame induces cortical inflammation and oxidative stress.

Researchers did a study with 30 adult male Wistar rats randomly divided into 3 groups. The control group received distilled water. The second group was given aspartame. And the third group was given aspartame and NAC. Oral administration was done in the morning daily for 90 days.

The study found that NAC affected Brain-Derived Neurotrophic Factor (BDNF) levels, blocked the COX-2 and PGE2 inflammatory enzymes, and reduced the expression of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) inflammatory cytokines in the rat cerebral cortex. They also found that NAC replenished glutathione levels.

The researchers concluded that NAC prevented neurotoxicity and improved neurological function, suppressed brain inflammation, and oxidative stress response.[vi]

  1. N-Acetyl L-Cysteine relieves depression. Major depressive disorder is one of the most common psychiatric disorders. It’s a burden on the individual, family and the community. And the pharmaceutical companies are making literally billions on selling various anti-depressants. Not treating the cause, producing a host of side effects, and in most cases just ‘dumbing down’ the symptoms.

But the pipeline for new anti-depressant drug discovery is at a near stand-still for treating problems like schizophrenia, bipolar disorder, depression and common forms of autism.

The good news is that neuroscience continues to work on the problem. And have shown that many of these disorders share inflammation and oxidative stress as part of their disease physiology.

Neuroscientists also discovered that associated pathways causing these diseases include a reduction in proteins that stimulate neuron growth (neurotrophins), increased apoptosis (cell death), and reduced energy generation in mitochondria.

It turns out that NAC seems to have multiple effects on all these pathways. NAC reduces the core symptoms of schizophrenia, reduces depression, and reduces cravings for a number of addictions including cocaine, cannabis and tobacco.[vii]

How things go bad

As we get older or suffer from chronic illness, our brain and body chemistry and energy metabolism changes.N-Acetyl-L-Cysteine-relieves-depression

↑ Oxidative stress in brain cells increase

↓ Free radicals damage neurons

↓ Dopamine receptors stop working

↑ Glutamate toxicity causes cell damage and apoptosis

↓ Brain-Derived Neurotrophic Factor (BDNF) declines

↓ Mitochondria energy declines

All of these changes are often attributed to chronic illness, lifestyle choices, and aging.

Unchecked, they could lead to neurodegenerative diseases like Parkinson’s, Alzheimer’s, major depression, schizophrenia, OCD, addictions, autism, and a drop in quality of life.

N-Acetyl L-Cysteine benefits

N-Acetyl L-Cysteine (NAC) is a slightly modified version of the sulfur-containing amino acid L-Cysteine. When taken as a supplement, NAC replenishes intracellular levels of the natural antioxidant glutathione (GSH). Restoring your cells’ ability to fight damage from reactive oxygen species (ROS).

Conventional medicine has used NAC for decades as an inhaled mucous thinner to treat symptoms of cystic fibrosis. NAC is given intravenously (IV) or orally as a treatment for acute acetaminophen poisoning. NAC quickly restores glutathione levels, averting permanent disability or death.

The nootropics community has recently discovered NAC as a way to suppress inflammation in the brain. NAC prevents oxidative stress on brain cells, eliminates free radicals, restores Brain-Derived Neurotrophic Factor (BDNF), rejuvenates dopamine receptors, and improves overall cognitive function.

NAC can help boost cognition, Long-Term Potentiation for long-term memory formation, short-term and working memory, improve your mood and quell anxiety.

How does N-Acetyl L-Cysteine feel?

Neurohackers report that supplementing with NAC could be the best nootropic they’ve ever used for their brain and overall health. Comments include:

  • Thinking is clearer (less brain fog)N-Acetyl-L-Cysteine boosts dopamine
  • Memory improves
  • Concentration and attention improves
  • Less anxiety
  • Less depression
  • Less irritable
  • Mood improves (like a ‘clean high’)
  • Symptoms caused by ADHD meds disappear
  • Obsessive Compulsive behavior decreases
  • Sleep quality improves
  • Energy levels increase
  • Weight maintenance is easier
  • Less flu and colds
  • Skin looks better
  • Feel younger
  • Hangovers are less severe

N-Acetyl L-Cysteine Clinical Research

N-Acetyl L-Cysteine increases dopamine

Treatments for Parkinson’s Disease are limited to replacing dopamine in the brain. As well as some medications designed to slow down the disease.

In 2016, researchers at Thomas Jefferson University showed that oxidative stress in the brain could play a critical role in the progression of Parkinson’s. And this stress lowers levels of glutathione, a compound produced in the brain to counteract oxidative stress.

Studies show that N-Acetyl L-Cysteine (NAC) helps reduce oxidative damage to neurons by helping restore the levels of the antioxidant glutathione.

In this study, Parkinson’s patients were placed into two groups. The first group received 50 mg/kg NAC intravenously (IV) once per week. And 600 mg of NAC as a supplement twice a day on non-IV days.

The second (control) group received only their standard Parkinson’s treatment. Patients were evaluated at the beginning of the study and again 3 months later.

The evaluation consisted of the Unified Parkinson’s Disease Rating Scale (UPDRS), and a SPECT brain scan which measures the amount of dopamine transporter in the brain.

Compared to controls, the patients receiving NAC had significant improvements in their scores. One of the study authors said, “We have not previously seen an intervention for Parkinson’s disease have this kind of effect on the brain”. This study demonstrated for the first time the direct effect of NAC on the brain’s dopamine system. NAC has the unique ability to enable dopamine neurons to recover their function.[viii]

N-Acetyl L-Cysteine repairs Traumatic Brain Injury

Traumatic brain injury (TBI) is a major public health issue affecting 1.7 million Americans each year.[ix] TBI can be caused by sports injuries, work accidents, car and motorcycle accidents, falls, and your wife hitting you over the head with a frying pan.

Many survivors end up with long-term or even permanent neurocognitive dysfunction. Affecting cognition, motor function (movement) and personality. These disabilities are estimated to cost $9.2 billion in lifetime medical costs and $51.2 billion in productivity losses.[x]

A major cause of TBI comes from blast exposure on the battlefield. Symptoms are similar to other causes of TBI; dizziness, hearing loss, headache, memory loss, sleep issues, and neurocognitive dysfunction.

In a brain subjected to TBI there is glutamate toxicity, free-radical injury to brain cells, electrolyte imbalances, mitochondrial dysfunction, inflammation, apoptosis (cell death) and stroke.[xi][xii]N-Acetyl-L-Cysteine relieves Traumatic Brain Injury

This double blind, placebo-controlled study was conducted with 81 active duty service members at a forward deployed field hospital in Iraq. All service members in this study were exposed to significant ordinance blast and met the criteria for TBI.

Service members were randomly assigned to receive either a placebo or N-Acetyl L-Cysteine (NAC) for 7 days. The resolution after 7 days of all the TBI symptoms listed above was the main outcome measure of this study.

The researchers concluded that NAC was a safe pharmaceutical countermeasure of blast-induced TBI. And that further work on long term outcomes and the potential use of NAC in civilian TBI is warranted.[xiii]

N-Acetyl L-Cysteine helps alleviate depression

Both depression and bipolar disorder are complicated by glutathione depletion. The researchers in this double-blind, multicenter, placebo-controlled study worked with 75 subjects with bipolar disorder.

Subjects received 1 gram of NAC twice daily for 24 weeks. NAC treatment caused a significant improvement with depression with those using NAC.

The researchers concluded, “NAC appears a safe and effective augmentation strategy for depressive symptoms”. In this case with people suffering from bipolar disorder.[xiv]

N-Acetyl L-Cysteine Recommended Dosage

N-Acetyl-L-Cysteine dosageN-Acetyl L-Cysteine (NAC) suggested dosage for cognitive benefit is 500 mg 3-times per day.

Clinical studies have found that doses up to 2,000 mg per day are safe and effective.

And one German study showed the safety of 2,800 mg per day for 3 months in patients with cystic fibrosis.[xv]

NAC has also proven effective against seasonal influenza and flu-like illnesses. One large study of older adults in Italy took 600 mg of NAC twice daily for 6 months. Only 25% of those adults who used NAC experienced flu-like episodes compared to 79% in the placebo group.[xvi]

N-Acetyl L-Cysteine Side Effects

N-Acetyl L-Cysteine (NAC) is the N-acetyl form of the naturally occurring amino acid L-Cysteine. NAC is considered non-toxic and very safe.

NAC is a slightly modified version of the sulfur-containing amino acid L-Cysteine. So NAC in powder form can have an unpleasant smell.

Very rarely can NAC cause nausea, vomiting, diarrhea or constipation. Even more rare are rashes, fever, headache, drowsiness, low blood pressure and liver problems.

Side effects can be a result of very high doses of NAC. And if you have a genetic condition called Cystinuria do not use NAC. This rare condition causes stones to form in the kidneys, ureter and bladder from cysteine. NAC is the N-Acetyl form of Cysteine.

One study has also found that long-term use of high-dose NAC can deplete your body’s stores of zinc. So if you are using NAC everyday you should also supplement with zinc and low dose copper.

Where to buy N-Acetyl L-Cysteine

N-Acetyl L-Cysteine (NAC) is available in powder, tablet and capsule form. NAC capsules and tablets were usually 500 mg.

Where to buy: I highly recommend: Life Extension – NAC

NAC is in short supply because on July 23, 2020, the FDA sent a warning letter to Purple Biosciences LLC about its NAC product. And asserted that NAC was illegally sold as a dietary supplement because it was approved as a drug September 14, 1963.  Several other letters were sent to supplement manufacturers. Since then NAC was difficult to find on Amazon or many of the other sites that used to sell NAC.

Several lawsuits were filed against the FDA. And NAC has since become easier to find in the supplements sections of online stores.

Nootropics Expert Recommendation

N-Acetyl L-Cysteine (NAC) 500 mg, 3-times per day

Nootropics Expert Tested and ApprovedI highly recommend using N-Acetyl L-Cysteine (NAC) as a nootropic supplement.

Your body does synthesize some L-Cysteine from methionine. And you can get L-Cysteine from foods such as dairy, poultry, pork, and some grains and nuts.

But most of us don’t get enough N-Acetyl L-Cysteine from our diet. So supplementation will help. And N-Acetyl L-Cysteine is a highly bioavailable form of L-Cysteine. So you should feel its effects faster.

NAC is helpful for most neurohackers to improve mood, memory, cognition, and concentration. And NAC helps alleviate brain fog, anxiety, and irritability.

NAC is especially helpful to those dealing with Obsessive Compulsive Disorder. And stacked with ADHD meds, NAC helps alleviate some of the negative side effects associated with stimulants.

If you can still find it, you can safely use up to 1,800 mg of NAC per day. The usual dose for cognitive improvement is 500 mg dosed 3 times throughout your day.

I recommend N-Acetyl L-Cysteine (NAC) from : Life Extension – NAC

REFERENCES

[i] Neuwelt E.A., Pagel M.A., Hasler B.P., Deloughery T.G., Muldoon L.L. “Therapeutic efficacy of aortic administration of N-acetylcysteine as a chemoprotectant against bone marrow toxicity after intracarotid administration of alkylators, with or without glutathione depletion in a rat model.” Cancer Research. 2001 Nov 1;61(21):7868-74 (source)

[ii] Scalley R.D., Conner C.S. “Acetaminophen poisoning: a case report of the use of acetylcysteine.” American Journal of Hospital Pharmacy. 1978 Aug;35(8):964-7. (source)

[iii] Neergaard L. “Most Popular painkiller is lead cause of acute liver failure” National AIDS Treatment Advocacy Project natap.org Dec. 25, 2005 retrieved June 17, 2016 (source)

[iv] Eakin K., et. Al. “Efficacy of N-Acetyl Cysteine in Traumatic Brain Injury” PLoS One. 2014; 9(4): e90617. (source)

[v] Hashimoto K., Tsukada H., Nishiyama S., Fukumoto D., Kakiuchi T., Shimizu E., Iyo M. “Effects of N-acetyl-L-cysteine on the reduction of brain dopamine transporters in monkey treated with methamphetamine.” Annals of the New York Academy of Sciences. 2004 Oct;1025:231-5. (source)

[vi] Saleh A.A.S. “Anti-neuroinflammatory and antioxidant effects of N-acetyl cysteine in long-term consumption of artificial sweetener aspartame in the rat cerebral cortex” The Journal of Basic & Applied Zoology Volume 72, October 2015, Pages 73–80 (source)

[vii] European College of Neuropsychopharmacology (ECNP). “Amino acid offers potential therapeutic alternative in psychiatric disorders.” Science Newsline Medicine sciencenewsline.com October 7, 2013 Retrieved June 18, 2016 (source)

[viii] Monti D.A., Zabrecky G., Kremens D., Lian T.W., Wintering N.A., Cai J., Wei X., Bazzan A.J., Zhong L., Bowen B., Intenzo C.M., Iacovitti L., Newberg A.B. “N-Acetyl Cysteine May Support Dopamine Neurons in Parkinson’s Disease: Preliminary Clinical and Cell Line Data.” PLOS ONE, 2016; 11 (6): e0157602 (source)

[ix] Faul M, Xu L, Wald MM, Coronado VG (2010) “Traumatic Brain Injury in the United States: Emergency Department Visits, Hospitalizations and Deaths 2002–2006”. Atlanta (GA): Centers for Disease Control and Prevention, National Center for Injury Prevention and Control. (source)

[x] Rutland-Brown W., Langlois J.A., Thomas K.E., Xi Y.L. “Incidence of traumatic brain injury in the United States, 2003.” Journal of Head Trauma Rehabilitation. 2006 Nov- Dec;21(6):544-8. (source)

[xi] Yi J.H., Hazell A.S. “Excitotoxic mechanisms and the role of astrocytic glutamate transporters in traumatic brain injury.”Neurochemistry International. 2006 Apr;48(5):394-403 (source)

[xii] Farkas O., Povlishock J.T. “Cellular and subcellular change evoked by diffuse traumatic brain injury: a complex web of change extending far beyond focal damage.” Progress in Brain Research. 2007;161:43-59. (source)

[xiii] Hoffer M.E., Balaban C., Slade M.D., Tsao J.W., Hoffer B. “Amelioration of acute sequelae of blast induced mild traumatic brain injury by N-acetyl cysteine: a double-blind, placebo controlled study.”PLoS One. 2013;8(1):e54163. (source)

[xiv] Berk M., Copolov D.L., Dean O., Lu K., Jeavons S, Schapkaitz I., Anderson-Hunt M., Bush A.I. “N-acetyl cysteine for depressive symptoms in bipolar disorder–a double-blind randomized placebo-controlled trial.” Biological Psychiatry. 2008 Sep 15;64(6):468-75 (source)

[xv] Dauletbaev N., Fischer P., Aulbach B., Gross J., Kusche W., Thyroff-Friesinger U., Wagner T.O., Bargon J. “A phase II study on safety and efficacy of high-dose N-acetylcysteine in patients with cystic fibrosis.” European Journal of Medical Research. 2009 Aug 12;14(8):352-8. (source)

[xvi] De Flora S., Grassi C., Carati L. “Attenuation of influenza-like symptomatology and improvement of cell-mediated immunity with long-term N-acetyl cysteine treatment”. The European Respiratory Journal. 1997 Jul;10(7):1535-41. (source)

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About David Tomen

David has been researching nootropics and brain optimization for over 10 years. When he's not writing about nootropics, he's travelling the world (45 countries so far), sailing, diving, studying neuroscience or sitting under an umbrella on Miami Beach. More...

Comments

  1. Jen says

    January 19, 2022 at 7:11 pm

    Hi David,

    I also have adult ADHD and take adderall daily. Will NAC provide the same enhancements and protections for Adderall users as it does for Ritalin users, as I know they work by different mechanisms? Thanks!

    Reply
    • David Tomen says

      January 20, 2022 at 5:57 pm

      Jen, NAC helps restore dysfunctional dopamine receptors which are affected by both types of stimulant. So my answer is ‘yes’ it will.

      Reply
  2. Young says

    January 12, 2022 at 1:02 pm

    How would one go about dosing NAC, NALT, and ALCAR, and is it safe?
    If so, how much should one take and when should they take it?

    Reply
    • David Tomen says

      January 12, 2022 at 6:05 pm

      Young, dosage recommendations and timing are included in each one of my reviews. I suggest you read each one. And then decide if you think it is safe after you read all the clinical evidence I have included in each review.

      Reply
      • Nick says

        January 18, 2022 at 6:17 pm

        Its no longer available from HR, do you have any other places I could get it?

        Reply
        • David Tomen says

          January 19, 2022 at 1:55 pm

          Nick, you can still get NAC from Double Wood Supplements.

          Reply
  3. Dmitri says

    January 10, 2022 at 12:52 pm

    Hi, David.

    Can i take ritalin 10mg – 3 times a day – and 500mg NAC, once a day? (every day).

    I’ve read in a website that NAC can cause blood circulation problems in lungs, it’s true?

    Thanks.

    Reply
    • David Tomen says

      January 11, 2022 at 4:24 pm

      Dimitri what you read about NAC and blood circulation is a lie. Ignore it. If it were true I would have included it in the Side Effects section of this review.

      Standard dosage for NAC is 500 mg 3-times per day. If you use it only once per day you will not receive its full benefit. You’ll get some benefit but not all.

      Reply
  4. Benjamin says

    December 26, 2021 at 2:26 am

    My Nac supplements came in 1000MG pills from Now

    is it okay to take that much, will it cause harm to my kidneys or liver been over 600MG at once?, Also, I want it to boost Glutathione while I sleep so is taking it an hour or 2 before bed good?

    Reply
    • David Tomen says

      December 26, 2021 at 2:22 pm

      Benjamin, you can safely use up to 2,000 mg NAC per day according to clinical studies. Check the “Side Effects” section above so you know what to watch out for. An it depends on the health of your liver. If this concerns you the best thing is to get labs done in 2-3 months to see if your liver is effected by using NAC.

      You should be OK taking Glutathione about 60 mins. before bed to boost this important antioxidant.

      Reply
      • Benjamin says

        December 27, 2021 at 7:58 pm

        Will NAC lower my Zinc levels?

        Reply
        • David Tomen says

          December 28, 2021 at 2:41 pm

          One study (https://www.ncbi.nlm.nih.gov/pubmed/1529808) has also found that long-term use of high-dose NAC can deplete your body’s stores of zinc. So if you are using NAC everyday you should also supplement with zinc and low dose copper.

          Reply
  5. Marek says

    December 22, 2021 at 6:23 am

    Hi, David. Is it safe to take 2g nac at once? i did 1g and no problem. I want to use it only before bed becuase nac blunts glutamte which i want to get flowing naturally whole day.

    Reply
    • David Tomen says

      December 23, 2021 at 4:22 pm

      Marek, it does not make any sense to use more than 500 – 600 mg NAC at a time because your body and brain can only use so much.

      And NAC ‘modulates’ glutamate. It does not “blunt” it. Which is only one of the reasons why it is beneficial to use NAC during your day.

      Reply
  6. Sean Yu says

    December 21, 2021 at 5:51 am

    Thanks David. Last time I had my bloods my liver counts was marginally high. I’ll definitely take your advice and monitor closely.
    If it does cause issues, does the recommended safe dose (2g) per day have to be split for liver health? Otherwise that might be a good option, just take once a day.l at the higher dose, which gives relief.
    Appreciate your advice

    Reply
    • David Tomen says

      December 21, 2021 at 4:51 pm

      Sean, that amount of NAC should be split into 3 doses spread about 5 hours apart. That may help.

      Reply
    • Ron says

      June 16, 2022 at 9:42 am

      Hi David,

      Have you read the studies about NAC being used up to 2700 mg for autistic individuals? One would need to take 900 mg 3 times a day.

      Also, can you take NAC with lexapro and guanfacine?

      Kind Regards,

      Ron

      Reply
      • David Tomen says

        June 16, 2022 at 3:51 pm

        Ron, 500 or 600 mg 3-times per day for autism. Keep in mind they often use higher doses in clinical studies because a lot of studies are only a few weeks at most. They need a higher dose to get the affect they’re looking for.

        Reply
  7. Sean Yu says

    December 17, 2021 at 9:20 pm

    David, NAC is very beneficial for my anxiety, but I need to take it at higher dosages. I’ve tried reducing back to 500mg – 3 times a day, or 800mg twice a day, but it doesn’t keep the anxiety in check. There is a lot of contradictory information on safe dose out there, so thought I’d check as I value your expertise on this matter. I’m 172 pound.
    To keep the anxiety at bay I take a total of 3 – 3.5g of NAC a day (split in 2 or 3 doses), which works well for me, but if I’m doing damage to myself I’ll have to re-explore other options.
    Appreciate your advice

    Reply
    • David Tomen says

      December 20, 2021 at 4:17 pm

      Sean, excessively high doses of NAC can cause liver problems. So I suggest that if you continue to use that high a dose get your liver numbers checked every few months just to be safe. The last thing you want is to have to wait for a liver transplant.

      Reply
  8. Todd Beal says

    December 9, 2021 at 9:19 pm

    David, would you recommend Setria Glutathione in addition to N-Acetyl L-Cysteine, or one to the exclusion of the other? Also, is N-Acetyl L-Cysteine as effective as Setria Glutathione for Rheumatoid and other autoimmune diseases (immune system regulation)? I cannot find any clinical studies that compare the two. Thanks for what you do here. I have studied your site for several months.

    Reply
    • David Tomen says

      December 10, 2021 at 4:29 pm

      Todd, your brain uses both Glutathione and NAC depending on the region and type of brain cell. They compliment each other. See my review of Glutathione here: https://nootropicsexpert.com/glutathione/

      Reply
      • Todd Beal says

        December 13, 2021 at 8:05 pm

        Thank you. I reviewed both articles, including your answers to commenters. That answered my question.

        My mother has rheumatoid arthritis. When I looked up L-Glutathione for RA, the clinical studies (for instance, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6661417/) indicated it regulates the immune system “cytokine storm” (not just for RA but for any autoimmune-type/systematic disease), just as in COVID-19, to reduce inflammation. In your experience, would NAC further regulate the “cytokine storm”, aside from additional Glutathione production?

        Reply
        • David Tomen says

          December 14, 2021 at 4:47 pm

          Todd, honestly I am not 100% sure but it likely does. See #1 under this section above “How does N-Acetyl L-Cysteine work in the Brain?”

          If I was dealing with rheumatoid arthritis I would personally use both. But it would be easy enough to test. Try glutathione on its own and see how it works. A couple days later add NAC and see if there was further improvement.

          Reply
          • Todd Beal says

            December 18, 2021 at 1:29 pm

            Many supplements take days/weeks to feel results. I hear you saying that L-Glutathione and NAC potentially take less time. Correct?

          • David Tomen says

            December 20, 2021 at 4:04 pm

            Todd, the nootropics that take awhile to feel are typically herbs and adaptogens and supplements that increase Nerve Growth Factor or BDNF. Amino acids and ezymes work right away and you should feel their effects within 20 – 30 minutes.

          • Todd Beal says

            December 18, 2021 at 2:15 pm

            Thank you very much!

  9. Vanessa says

    November 30, 2021 at 5:50 pm

    Hi David,
    I was wondering if you had any recommendations for supplements to stack with NAC to reduce anxiety and OCD symptoms.
    I am currently taking Ashwagandha (KSM-66) and Shilajit.

    Thanks for your help!

    Reply
    • David Tomen says

      December 4, 2021 at 11:26 am

      Vanessa, do a search using the search function top right above the top menu. And search for the keyword “OCD”. You will get a list of supplements proven in clinical studies and by real people to reduce OCD symptoms.

      Reply
  10. Tamra Hale Litz says

    November 30, 2021 at 5:17 pm

    I saw it being sold on Amazon today. They must have changed their mind?PURE was being sold for 60.00 for 90 caplets. I found it for half elsewhere.

    Reply
    • David Tomen says

      December 4, 2021 at 11:35 am

      Tamra, I haven’t seen any NAC on Amazon for months because of the ban by the FDA. And nothing has changed in that department as far as I can tell.

      Reply
  11. Jon says

    November 25, 2021 at 1:49 pm

    I had a question regarding the correlation of cysteine levels and cardiovascular disease as it relates to NAC. That is, how does NAC affect circulating cysteine levels? Also, I noticed chest pain when I use 1000 mg of NAC, which is in fact a side effect. Any thoughts would be great.

    Reply
    • David Tomen says

      November 29, 2021 at 3:08 pm

      Jon, side effects are usually caused by too high a dose of NAC so try reducing your dose to 500 mg and see if that solves your problem.

      All of the side effects associated to NAC that I know of are included above in the “Side Effects” section of this article.

      Reply
  12. Brian Austin says

    November 20, 2021 at 11:09 am

    I have a powder form of NAC from Nootropics – how much powder (approximately) would be equivalent to 500 mg?

    Thank you!

    Reply
    • David Tomen says

      November 29, 2021 at 5:18 pm

      Brian, the only way to measure this accurately is to use a small scale like this one: https://amzn.to/3EaPEoU

      Reply
  13. LuAnne says

    November 15, 2021 at 2:23 pm

    Hi Dave,
    I’m hoping I didn’t miss this, but I did look a couple times before submitting this question. Is NAC water soluble, or should it be taken with food? Also, do people typically feel the effects right away, or does it take time?

    Thank you!

    Reply
    • David Tomen says

      November 18, 2021 at 6:23 pm

      LuAnne, NAC is water soluble so you can take it with or without food. And people react differently to this and every supplement. You may feel the effects within the first hour or it could take several days of consistent use of three times per day. Either way NAC is providing the benefits you read above whether you “feel it” or not.

      Reply
  14. Joaquin says

    November 11, 2021 at 2:27 pm

    David, I have some questions that would help me a lot to answer please
    According to your experience is there any negative effect in consuming more than 1 mg as it contains perfonmance lab vision, or why don’t you consume more than 1 mg?

    -The antioxidant effects of astaxanthin are so effective as NAC, Or would you prefer NAC as an antioxidant?

    -Is this astaxanthin supplements is good enough?

    NOW Supplements Astaxanthin 4 mg

    Reply
    • David Tomen says

      November 12, 2021 at 3:43 pm

      Joaquin, the recommended nootropic dosage of Astaxanthin when used on its own is 4 – 16 mg per day. And the NOW Supplements Astaxanthin looks like a good choice.

      NAC and Astaxanthin are two very different supplements. NAC is a precursor to Glutathione which is your master antioxidant. You can see how Astaxanthin works here: https://nootropicsexpert.com/astaxanthin/

      In this case one is not better than the other. Both offer their own benefits and it wouldn’t hurt to use both.

      Reply
  15. William Mays says

    November 3, 2021 at 1:44 pm

    I use NAC every day. Recently, i came across an older article stating it could cause pulmonary arterial hypertension. However, it did not make clear of the dosage. Have you heard of such a thing? Thanks.

    Here is a link to the article in question: https://www.sciencedaily.com/releases/2007/09/070904175353.htm

    Reply
    • David Tomen says

      November 3, 2021 at 3:04 pm

      William, thanks for linking to that article. But I would not worry about it. This was a study done in 2007 with mice, never tested in humans, and it’s a press release. Not a peer-reviewed clinical study.

      I’ve been using NAC 3-times per day for years and have had my red blood cell count an oxygen levels checked more times in the past year that I care to remember. And have not had a problem. No one else has reported this either.

      Reply
      • William Mays says

        November 4, 2021 at 9:13 am

        Thanks for the reply, much appreciated by friend.

        Reply
  16. Benjamin says

    October 30, 2021 at 1:37 am

    Can NAC cause gout? 1000MG daily

    Reply
    • David Tomen says

      October 30, 2021 at 4:42 pm

      No

      Reply
  17. Andrew Richardson says

    October 29, 2021 at 3:59 am

    Can I take

    NAC – 500MG
    ALCAR – 500MG
    DHA – 1200MG
    Inositol – 1000MG
    L-theanine – 300MG

    Daily, all at the same time in the morning

    Reply
    • David Tomen says

      October 30, 2021 at 5:20 pm

      Andrew, these are the dosages and timing you need:

      NAC – 500MG 3-times per day
      ALCAR – 500MG 3-times per day
      DHA – 1200MG in the morning
      Inositol – 1000MG in the morning
      L-theanine – 100MG 3-times per day

      If you try using 300 mg L-Theanine in the morning it’ll put you to sleep.

      Reply
  18. Jurgen says

    October 16, 2021 at 5:23 pm

    How does NAC compare to taking a high concentrated Brocolli extract? Is Brocolli extract better than NAC? Can it replace NAC or does taking both have synergetic effects?

    Reply
    • David Tomen says

      October 16, 2021 at 5:57 pm

      Jurgen, it depends on what you mean by “Broccoli extract”. Because broccoli contains glutathione (https://nootropicsexpert.com/glutathione/) and Sulforaphane (https://nootropicsexpert.com/sulforaphane/). Check out my review on each to see exactly how each supports your immune system. NAC is a precursor to the production of glutathione.

      So, I suppose you could say they act synergistically. But each has a different mechanism of action in your body.

      I would not say that one is better than the other. You never hear of someone using Broccoli extract in the ER. But NAC is used in ERs.

      Reply
  19. Scott says

    October 11, 2021 at 10:53 pm

    Is there a way for the laymen to make NAC at home? With the drug companies and their lackeys clamping down on cheap beneficial substances like this, it would be extremely beneficial to know how to make these ourselves.

    Reply
    • David Tomen says

      October 12, 2021 at 3:10 pm

      Scott, unless you have a couple of million to invest in equipment I’m afraid the next best thing is to call your congressman or senator and tell them to keep their hands off your NAC.

      Reply
  20. Ron says

    October 11, 2021 at 1:02 am

    Can children use NAC? If so, is 1800 mg a day still the recommended amount?

    Reply
    • David Tomen says

      October 11, 2021 at 11:25 am

      Ron, that’s a question for your kid’s doctor to answer. And NAC is something your doctor should be familiar with because they use NAC in emergency rooms.

      But there are no clinical studies using NAC with kids as far as I know. So, we do not know what the safe amount is for a kid. Common sense would be to start with 1/3 the adult dose.

      Reply
      • Ron says

        October 23, 2021 at 12:17 am

        https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5788395/#!po=8.03571 Have you read this article? It looks like a study on children with psychiatric disorders.

        Reply
        • David Tomen says

          October 26, 2021 at 4:46 pm

          Ron, first time I’ve seen that one but it looks like a good review of all the clinical studies using NAC in kids.

          Reply
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