NAC Cysteine

NAC Cysteine has a very wide range of useful therapeutic effects: for depression, bipolar depression, addiction, anxiety, heavy-metal and liver detoxification.
In my practice I routinely prescribe NAC cysteine when I start with a new client, besides its antidepressant anti-addiction and antianxiety effects it reduces neuro-inflammation, oxidative/free radical stress and toxic heavy metals (if present), if left untreated either one of these can prevent successful treatment and recovery. In the dosage range I prescribe it is considered safe and non-toxic furthermore it’s one of the few antidepressant remedies that people with bipolar syndrome can safely use without the risk of it flipping them into mania.


What is NAC cysteine and how does it work?

Cysteine is an amino acid found in all protein foods with a very wide range of therapeutic effects, the NAC form of cysteine is a more stable form of cysteine.
NAC cysteine glutamate and over-activity in the brain
There’s a natural process that pumps NAC cysteine into our neurones and pushes the stimulatory neurotransmitter glutamate out of the cells, this has the effect of reducing glutamate activity. The neurotransmitter glutamate increases brain activity and when it is excessive it can whip-up anxious thoughts circulating in the mind and drive compulsive behaviours like OCD and addiction. Furthermore NAC supplementation restores healthy glutamate balance after cocaine and drug use.

NAC cysteine is a powerful antioxidant that protects the brain and liver
NAC cysteine is a used by the body to make the antioxidant free radical scavenger glutathione. There’s a growing understanding that mental health problems (including major depression, bipolar syndrome, anxiety disorders, schizophrenia Alzheimer’s disease and OCD) involves damage and shrinkage to specific areas of the brain and inflammation and oxidative or free radical stress believed to be key causes of this damage. Supplementing NAC cysteine is a very effective way to protect the brain from oxidative/free radical damage and neuro-inflammation.
The anti-oxidant effects of NAC cysteine may also help protect and restore damage to dopamine pathways in the brain induced by recreational drug use[i]; furthermore supplementing cysteine increases the liver’s ability to detoxify drugs from the body.

NAC Cysteine for Anxiety

The neurotransmitter glutamate and GABA oppose each other, glutamate stimulates and perpetuates transmission whereas GABA puts the brakes on and stops thoughts circulating around and around in the mind. Excessive glutamate activity and or inadequate GABA can create and intensify thoughts and feelings of anxiety, worrying and anxious thoughts can literally go around and around in the mind unchecked and escalate into very intense and unpleasant feelings of anxiety. NAC helps anxiety by reducing glutamate activity, it moves glutamate to the outside of the neurones which has the effect of reducing glutamate’s stimulatory effects.
There’s an increasing area of research that is focusing on the problem of excessive levels of glutamate causing anxiety rather than just deficient levels of GABA[ii]. Some types of anxiety may originate from the brain making unwanted connections for example connecting spiders or mice to extreme danger however general anxiety disorder or GAD may be more due to a chemical imbalance with excess glutamate and inadequate GABA.
Ideally to combat and overcome anxiety you should combine several strategies including:
  • remedies to dampen down excessive glutamate activity (NAC cysteine, zinc),
  • remedies that increase GABA activity and sensitivity to GABA (ashwagandha, L-theanine, taurine, passionflower, lithium orotate, magnesium, P-5-P [B6]),
  • psychological and psychotherapy techniques to remodel stressful and traumatic memories and the way the brain connects to them,
  • brain training techniques to remodel key structures in the brain that control anxiety such as mindfulness meditation that has been shown to diminish the size and activity of the amygdala (the brains alarm system) and increase the size and strength of the prefrontal cortex that has the ability to ignore and switch off anxious thoughts.
See my other pages on Treating GABA Deficient Anxiety

NAC Cysteine for Addiction Recovery

Several studies (both animal and human) have shown supplementing NAC can reduce addictive behaviour (both craving and relapsing) for drugs including cocaine, heroin and nicotine, it has even been shown to reduce gambling addiction[iii], there aren’t many substances that can do this making NAC an incredibly valuable supplements.
The mechanism whereby NAC cysteine combats addiction is not fully understood, elsewhere I discuss the central role of dopamine in driving addiction but it is also well documented that imbalances in the brains glutamate balance is also involved in addiction. Glutamate is involved in driving reward seeking, repetitive/compulsive behaviours, reinforcement and relapse.
NAC appears to produce its anti-addiction effects by restoring healthy glutamate balance. Elsewhere I discuss how you can take control of your dopamine to combat cravings and addiction, you can combine this with NAC for a more comprehensive treatment.
It’s unclear whether supplementing NAC cysteine is helpful to reduce the craving for cannabis it does however appear to improve ‘emotional reality’ and focus in marijuana users, in my practice I routinely prescribe NAC as part of the treatment for cannabis withdrawal, to help detoxification and concurrent issues such as depression and dependence on other drugs.

NAC Cysteine for Depression and Bipolar Depression

NAC cysteine can be a very powerful and useful antidepressant for both unipolar and bipolar depression. I regularly prescribe it to my patients and I take it personally off and on several months of the year as part of my wellness regime. My observation is that NAC cysteine is relatively slow acting, expect it to take a 4 to 6 weeks before you feel the antidepressant effects.
NAC cysteine works without directly boosting serotonin or dopamine, so it can be taken at the same time as SSRI’s and SNRI’s antidepressant drugs without the risk of it producing serotonin syndrome.
For bipolar depression NAC is particularly useful because it does not run the risk of flipping you into mania which is a risk with most antidepressant remedies, there’s actually a little evidence that NAC may even help control mania[iv][v]. Furthermore addictions of all kinds are a common feature of bipolar syndrome so the anti-addiction properties of NAC make it a very useful remedy for people with bipolar.
See Serotonin Deficient Depression, Dopamine Deficient Depression, Bipolar
Exactly how supplementing NAC has an antidepressant effect is not clear, one of its effects is to significantly increase the production of glutathione one of the body’s most powerful and important free radical scavengers and detoxifiers. Increasing glutathione levels reduces inflammation and free radical damage to the brain both of which contribute to mental health problems. You can buy glutathione as a separate supplement but it’s better to supplement NAC cysteine because glutathione is not effectively absorbed.
Another effect of NAC cysteine is that it binds toxic heavy metals particularly mercury found in silver dental fillings and vaccinations, even in very low concentrations -parts per million- of heavy metals can downgrade brain health and our ability to manufacture neurotransmitters.

Dosage, Purchasing and Toxicity

For depression take: 1200 mg once a day on an empty stomach.
The several studies showed that there was no increased effectiveness in using dosages above 1200 mg so this has now become the standard dose I recommend.
For anxiety take: either 1200 mg once a day on an empty stomach as above or try 800 to 1000 mg twice a day.
Typically NAC is sold in 600 mg capsules however you can also find 500 mg. It’s fairly expensive and you may choose to buy it in powder for at a considerably reduced expense however I must warn you that it has a quite unpleasant taste, it’s also not particularly easy to dissolve. Buying it in powder form does however give you the option to carefully titrate the most effective dosage, to do this you will also need to have accurate scales that go down to at least one and ideally two decimal places, accurate scales can be cheaply purchased today.
CAUTION: doses of 7000 mg or above can become quickly toxic, the maximum amount I prescribe is 1200 mg twice a day for heavy metal detoxification.
It’s very rare that some people have a bad reaction to sulphur and NAC cysteine is a sulphur containing amino acid; it may be an allergic reaction or are genetic inability to process sulphur, either way if you can’t tolerate supplemental sulphur NAC cysteine is not for you.

My Recommendation

when you start using natural remedies to treat your mental health problem I recommend adding 1200 mg of NAC cysteine to your initial prescription for a period of at least three months, besides its antidepressant and anti-addiction effects the increased glutathione and reduction in possible metal toxicity will facilitate a better outcome.
[i] Ann N Y Acad Sci. 2004 Oct;1025:231-5. Effects of N-acetyl-L-cysteine on the reduction of brain dopamine transporters in monkey treated with methamphetamine. Hashimoto
[ii] CNS Spectr. 2005 Oct;10(10):820-30.The role of glutamate in anxiety and related disorders. Cortese BM1, Phan KL. PMID: 16400245
[iii] (PMCID:PMC 3545354) the Sistine/glutamate antiporter system in health and disease: from molecular mechanisms to novel therapeutic opportunities.
[iv] Aust N Z J Psychiatry. 2013 Jun;47(6):564-8. doi: 10.1177/0004867413481631. Epub 2013 Mar 14. A preliminary investigation on the efficacy of N-acetyl cysteine for mania or hypomania. Magalhães PV1 et al.
[v] J Psychiatr Res. 2015 Jun;65:71-9. doi: 10.1016/j.jpsychires.2015.04.011. Epub 2015 Apr 18. The effects of n-acetylcysteine and/or deferoxamine on manic-like behavior and brain oxidative damage in mice submitted to the paradoxal sleep deprivation model of mania. Arent CO1, Valvassori SS2,
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