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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. Marie Bev says

    December 13, 2022 at 9:03 pm

    I received an order of nootropics NAC powder a few months ago. Nowhere on the canister or inside the shipping box was there any instructions as to how much to take. I see on another NAC product from a different company there is a 600mg suggested amount to take per day and a scoop is included for measurement. On my nootropics, the only measurement on the label is for 400 grams, however, there is no scoop inside or other measurement device.

    So how much do I take per day, and must I do the math, and lacking a scoop, do I have to weigh it or what?

    Reply
    • David Tomen says

      December 16, 2022 at 3:33 pm

      Marie, the recommended adult dosage for NAC is 500 mg 3-times per day. If you have a powder then use a scale to measure it: https://geni.us/6qB0s

      Reply
  2. Cristina says

    October 17, 2022 at 9:48 am

    Someone referred to this study in one of the comments but did not link it, here is the article about it and link to the study: https://www.science.org/content/blog-post/n-acetyl-cysteine-warning-shot?cookieSet=1

    In short: NAC showed protective effects against cell aging and oxidative stress in lungs, but also resulted in more tumors, potentially because diseased tumor-starting cells that would have been destructed were protected by NAC, along with healthy cells.

    “The best guess is the cell senescence pathway that seemed to be inhibited with the NAC: some of these are in fact cells that should have died and didn’t, and went on to become cancerous.”

    From the study: “Altering the cell senescence process, however, may produce undesirable consequences, since senescent cells are well known to constitute a barrier to cell transformation and tumorigenesis.”

    Obviously this gets very complex, but it is a very interesting study.

    Reply
    • David Tomen says

      October 17, 2022 at 4:00 pm

      Cristine, interesting article. This is the link the the study he was referencing: https://insight.jci.org/articles/view/127647.

      But big caveat here. The study was done with aging mice. It’s never been shown in humans. But if I was dealing with lung cancer I’d likely not use NAC just to be on the safe side.

      Reply
  3. David says

    October 12, 2022 at 6:24 pm

    Hi David, thank you for taking the time to answer these questions.
    I am using nac as an adjunct therapy to a small amount of Zyprexa. The nac not only helps some lingering cognitive issues I have remaining (and insomnia) but also helps alleviate some of the side effects of the antipsychotic. The problem lies in the fact that the supplement causes me to have severe unusual body odor. I currently use life extension but have tried other brands and there doesn’t seem to be much of a difference. Do you have any insight on how to counter this effect? I have seen complaints about this in other places on the internet but with no real solutions (other than liquid chlorophyll).
    I work closely with people in the healthcare industry and I really want to continue using this very helpful supplement so thank you for knowledge!

    Reply
    • David Tomen says

      October 14, 2022 at 3:45 pm

      David, NAC is a sulfur-based amino acid and smells like sulfur. There is no getting away from it because it is what it is. A sulfur-based compound.

      Reply
  4. salem says

    October 11, 2022 at 2:24 pm

    hi david

    can i take 500mg of NAC with 1000-1500mg of l-orthinine , all together at the same time, before going to sleep ?

    Reply
    • David Tomen says

      October 12, 2022 at 1:58 pm

      Salem, why are you using l-ornithine? NAC and l-ornithine are completely unrelated so I don’t see a problem. Although the only thing I know about l-ornithine is it is used to create urea.

      Reply
  5. Elisabeth says

    October 11, 2022 at 5:36 am

    Thank you. Very helpful information.

    Do you have insight or suggestions as to the impact of taking NAC or the suggested timing relative to daily intermittent fasting? Few mentions of antioxidants limiting ketosis and reducing fasting benefits. Any feedback appreciated.

    Reply
    • David Tomen says

      October 12, 2022 at 2:14 pm

      Elisabeth, I do not see how NAC could break a fast. It is a precursor to the synthesis of Glutathione which is your master antioxidant. Recommended adult dosage of NAC is 500 – 600 mg 3-times per day.

      Reply
  6. jason says

    September 19, 2022 at 2:23 pm

    hi David, i posted a previous question but it was deleted, whys that?
    I have been using NAC for one month, and in the second month i noticed that may increase cholesterol, is that possible?

    The product generally is great, but something happened out of the blue and i had to stop it, any more research available i can read perhaps/.

    Reply
    • David Tomen says

      September 20, 2022 at 2:47 pm

      Jason, no one deleted our comment. I’m just now getting around to answering them.

      NAC increases HDL Cholesterol but has no effect on LDL cholesterol.

      Reply
      • jason says

        September 20, 2022 at 7:09 pm

        wow, i could feel it, so my assumption were correct, what i got was same pain in the vain from both lower calf, but in 4 days with Vit E, i sort this matter too.

        May i ask, if 3 per day increases hdl, one per day for the pleasure of the feel that gives, should be all right is it?
        Is there anything else better for cholesterol level checkup while taking Nac?

        Reply
        • David Tomen says

          September 21, 2022 at 2:36 pm

          Unrefined coconut oil improves LDL to HDL ratio. Myo-inositol can help lower LDL-cholesterol, C-reactive protein and blood glucose levels while increasing HDL-cholesterol.

          Vitamin B5 (Pantethine) increases HDL Cholesterol while decreasing LDL. Niacin significantly increases HDL-cholesterol, decreases LPL-cholesterol and triglycerides.

          I personally use Unrefined coconut oil, BioActive B-Complex, NAC, and Berberine and my levels are now normal.

          Reply
  7. Harry says

    September 18, 2022 at 4:21 pm

    hi David thank you for all this info. I hear conflicting reports about NAC and cancer, some says it protects/prevents others say it promotes. Have you seen anything on whether it is safe? thanks,

    Reply
    • David Tomen says

      September 20, 2022 at 2:59 pm

      Harry, NAC does NOT promote cancer. It has been used as a dietary supplement for decades and is even used in the ER.

      I suggest you follow the money with whomever is spouting that kind of false information. Chances are high it started with someone who owns a pharmaceutical company. The same people who tried to get the FDA to ban NAC last year. Because they want to make a drug out of it.

      Reply
      • Harry says

        September 20, 2022 at 3:30 pm

        Thanks David,

        I have been wanting to take it for some time as I have COPD and I hear it helps with that. Thanks.

        Reply
  8. Thomas, says

    September 17, 2022 at 2:09 am

    Sir,

    I’ve read about product GLYTEINE. It could be marketing ploy, but they claim that NAC doesn’t raise glutathione, because cysteine is allready abundant in food and it isn’t the limiting factor. It confuses me, because all views (pro and contra) are supposedly backed by clinical studies.

    I would appreciate your opinion. Thanks,
    Thomas

    Reply
    • David Tomen says

      September 17, 2022 at 3:19 pm

      Thomas NAC is a precursor to the production of glutathione. And this has been well established for decades.

      Reply
      • Thomas says

        September 17, 2022 at 11:28 pm

        I will take NAC to help alleviate Parkinson’s, through raising glutathion level, which is by this disease at low level. Hopefully it may help.

        Thanks,

        Reply
  9. Danny O says

    September 9, 2022 at 3:15 pm

    Regarding dosage, emerging longevity research indicate higher doses, like 3 grams a day especially for 50 years and up, are very beneficial. I don’t know that these higher doses are additionally beneficial cognitively, but increasing lifespan is certainly a good incentive.

    Reply
  10. Brad says

    September 3, 2022 at 5:12 pm

    David,
    Thanks for your work!
    I came across this -N-Acetyl Cysteine Ethyl Ester on Amazon. It says it is 20x more effective than NAC and crosses the blood-brain barrier, which it says NAC doesn’t. It is also much more expensive. What are your thoughts?
    Thanks,
    BW

    Reply
    • David Tomen says

      September 5, 2022 at 6:07 pm

      Brad, NAC easily crosses the blood-brain barrier and you get its benefits within 30 minutes of taking the supplement. Sounds like someone is doing their best to scare you to increase their profits.

      Reply
  11. Angela says

    August 14, 2022 at 4:57 pm

    We have a 4 year old grandson who was diagnosed with autism. Are there any supplements that can help children with autism?

    Reply
    • David Tomen says

      August 16, 2022 at 4:45 pm

      Angela, I do have a list of supplements proven to help with autism. But I haven’t written an article about this nor do I think I will. I have however done several consultations with parents of autistic kids. It takes about an hour to go through the list to explain it all. I’m happy to do a consultation with you if you are willing: https://calendly.com/davidtomen/60-minute-consultation-with-report

      Reply
  12. Claudia says

    August 12, 2022 at 8:33 pm

    Can I take NAC/L tyrosine and Agmatine at night? I read in your answer above that 500mg of NAC is not sufficient. Should I increase it to 3x/day? With Ritalin?

    Reply
    • David Tomen says

      August 14, 2022 at 3:04 pm

      Claudia, you should be using NAC 500 mg 3-times per day and 500 mg L-Tyrosine twice per day (morning and noon). And definitely NOT before bed if you want to get any sleep.

      Reply
  13. Jatin says

    August 12, 2022 at 6:23 pm

    Hi Sir,

    Do we have to take NAC on an empty stomach or after a meal?

    Thanks.

    Reply
    • David Tomen says

      August 14, 2022 at 3:06 pm

      NAC is water soluble so you can take it with or without a meal. It doesn’t matter.

      Reply
  14. Ron says

    August 6, 2022 at 10:54 pm

    Hi David,

    Can you take NAC with Quillichew or should it be taken at different times of the day? Also, what benefits can you get from taking both?

    Reply
    • David Tomen says

      August 9, 2022 at 6:16 pm

      Ron, I use NAC with Ritalin. Because it helps restore dysfunctional dopamine receptors. It should work with that drug as well.

      Reply
      • Ron says

        August 12, 2022 at 9:13 pm

        David, to clarify, are you saying you take Ritalin and NAC together? At the same time?

        Reply
        • David Tomen says

          August 14, 2022 at 3:03 pm

          Yes

          Reply
          • Ron says

            August 16, 2022 at 5:19 pm

            Thank you.

  15. STEVEN SURRY says

    August 5, 2022 at 6:43 pm

    So far as I know nobody in my family has cystinuria. Since taking 1200 mg/day of NAC I’ve noticed decreased urine flow and now a burning whenever I urinate. Do you suggest discontinuing NAC entirely or reducing my daily intake to 600 mg/day.

    Reply
    • David Tomen says

      August 9, 2022 at 6:23 pm

      Steven, if the has only happened since you started NAC then it sounds like it is the wrong supplement for you.

      Reply
  16. Nitin says

    July 24, 2022 at 2:35 pm

    Sir , is it true ,using antipsychotic medicine causes upregulation of dopamine receptors , as the dopamine receptors blocks to compensate them more new receptors grow. What do you think about it ? If medicine used for short duration.

    Reply
    • David Tomen says

      July 24, 2022 at 5:28 pm

      Nitin, what med are you referring to specifically?

      Reply
      • Nitin says

        July 26, 2022 at 1:46 pm

        Actually sir I am talking about the common process of antipsychotic drugs which they perform by blocking dopamine receptors mostly de receptors.

        Reply
        • David Tomen says

          July 26, 2022 at 4:57 pm

          It depends on the med. Many of these meds end up desensitizing the relevant receptor if used long-term. I always defer to a natural method if possible to get the benefit you are looking for. They are generally much safer and as effective as many of these drugs.

          Keep in mind I’m not a doctor and I am NOT anti-pharmaceutical. I need to use some of them for various things myself. But if I could do it naturally I would without question.

          Reply
  17. Barney says

    July 23, 2022 at 9:10 pm

    Hi David
    What are your thoughts on whether NAC should be cycled a) for effectiveness (ie do people get a tolerance) and b) for safe use? I use 1800mg a day as per your advice, but have in one serving as it’s the only way I feel the benefit.
    Thanks

    Reply
    • David Tomen says

      July 24, 2022 at 5:41 pm

      Barney, 1,800 mg NAC is enough. I prefer using 3 doses of 600 mg each because that keeps a steady amount of glutathione in your system. There is no need to ‘cycle’ NAC.

      The half-life of NAC is 5 – 6 hours so if you use 1,800 mg all at once you not get its benefit for half the day.

      Reply
  18. Aleksander says

    July 18, 2022 at 10:24 am

    Hi David! I was diagnosed as 22 y.o. ADD yesterday. I can’t describe how sad I feel right now, my life could be so much easier if I knew this years ago…

    I’m very afraid about ritalin long term side effects.

    1. Can I increase NAC dosage from 1800mg to 2400mg daily?

    2. Do you recommend inositol to support ritalin use?

    And yes I’ve seen your ADHD article, it’s priceless.

    Have an amazing day David!

    Reply
    • David Tomen says

      July 18, 2022 at 1:53 pm

      Aleksander, be grateful that you learned this at 22 years and not 20 years from now. That’s what happened to me and I wonder what my career would have looked at if I had been diagnosed in my 20s.

      You should not be using anymore than 2000 mg NAC per day. Anything over 1,500 mg per day will not provide any more benefit.

      Ritalin has been around since the 1950s and has the longest track record of any stimulant drug. It also has the safest long-term usage profile compared to any other ADHD drug other than Modafinil.

      The best thing you can do is follow my ADHD protocol on that ADHD page which includes supplements to boost BDNF to make sure you support neurogenesis. And do any ongoing repair IF Ritalin causes any damage to receptors or synapses.

      Ritalin will work better if you support dopamine and acetylcholine as well. You just need to find the right dosage for your system. And a 3rd dose later in the afternoon will prevent the stimulant crash too.

      Reply
  19. anthony says

    July 17, 2022 at 8:18 am

    Hi battling benzo dependency and more tolerance wd if that is the correct term.

    Some people recommend using NAC to balance gaba/glutamate levels in the brain and say it helps for anxiety too.

    My question is will it help if you take it 600mg a day cause i don’t have money to take it 3 times a day.

    Am i waisting my time or is it worth a shot? Also, how long before it starts working for anxiety? Also to balance gaba/glutamate levels

    Reply
    • David Tomen says

      July 17, 2022 at 2:56 pm

      Anthony NAC works with glutamate and dopamine. Not GABA. The standard adult dosage is 500 mg 3-times per day. One 500 mg dose is not going to give you much of a benefit. At that dose you should experience the full benefit within 2 weeks.

      Reply
  20. Sunny says

    July 14, 2022 at 5:23 pm

    Does NAC is really helpful in unblocking blocked dopamine receptors by antipsychotics because some information says long term use of anti psychotics permanently blocks or dysfunction dopamine receptors.Is it alone helpful or some other medicines are required for unblocking dopamine receptors.

    Reply
    • David Tomen says

      July 15, 2022 at 1:09 pm

      Sunny, there is not such thing as “blocking” dopamine receptors. You can inhibit them which prevents dopamine from attaching to the receptor. But it does not a “block” it.

      NAC helps restore dysfunctional dopamine receptors.

      Reply
      • Sunny says

        July 15, 2022 at 2:15 pm

        Sir can you suggest me best brand of NAC , if it is not available in my country india can you ship it to my address.

        Reply
        • David Tomen says

          July 17, 2022 at 3:49 pm

          Sunny, this is the brand of NAC I use: https://nootropicsexpert.com/go/life-extension-nac/. I do not know if they ship to India however. Once on their website you can ask them if they do ship to India.

          Reply
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