NAC: Just Two Good

Words: Dr Richard FIRSHEIN

Free radicals. When I was in medical school, I rarely heard a word about them.

Only a small group of ‘kooks’ would rave about the powers of vitamins and minerals. It wasn’t until my own struggles with asthma in the late 1980s that I began to appreciate the benefits of antioxidants; only then did I appreciate the genius behind the discovery of free radicals, how important it is to combat free radical production, and how crucial antioxidants are in preventing disease.

Vitamins C and E helped me escape the respiratory infections I’d had every year of my life.

Free radicals are highly charged molecules bearing an extra electron. That electron makes them extremely unstable. Imagine them as lightning bolts crashing into cells and causing damage.

How do these unimaginably tiny particles inflict their widespread damage on your body? Surprisingly, it’s the very defence mechanisms that our bodies employ for safety that release free radicals into our systems. And, it’s the very air we breathe that fuels them. Oxygen is essential for life. But oxygen can turn against us. That’s because each cell produces both energy and free radicals.

Free Radicals: Two Faces

Two per cent of the body’s oxygen actually undergoes free radical reactions. Free radicals are unstable, and so they streak through us, searching everywhere for extra electrons to bond with to help them stabilise, and inevitably those electrons are snatched from our other cells. This path of destruction, like an atomic bomb, is a series of chain reactions in which free radicals steal electrons from each other, attacking cell membranes and creating even more hyperactive free radical molecules in the process. In their wake, they leave behind tissue and organ damage. In excess, this can lead to a shocking number of health problems, from cancer to liver disease, cataracts, and emphysema.

Why does our body generate free radicals in the first place? One reason is because they’re such powerful warriors, and we need them to kill invading microbes. Our white blood cells release a caustic peroxide designed to kill whatever comes its way. This peroxide releases strong free radicals — it’s actually the same substance found in products we use to clean our homes and kill germs.

Chase Them Now

The good news is that our bodies are designed to mop up these free radicals after they’ve done their job. But, in today’s world, that simply isn’t enough.

Close to 200 million tons of pollutants are released into the atmosphere each year in the United States alone, and most of these contaminants promote harmful free radicals.

Every time you walk past a bus belching out a cloud of fumes, clean your floors with ammonia or chlorine bleach, spray your garden with pesticides, pump fuel into your tank at the gas station, or inhale ozone from smog, or as a by-product of computers and photocopiers, you are subjecting your lungs to free radicals.

Even greasy foods like hamburgers, pizza, and French fries contain harmful fats that become oxidized, creating free radicals.

Perhaps, the absolute worst — and most ubiquitous — free radical damage stems from cigarette smoke, whether you puff it out or get it secondhand. In the face of this onslaught, our bodies need supplemental anti-oxidant assistance.

Antioxidants chase free radicals through the body, stabilising and neutralising them. Among the most powerful of antioxidants ranks an amino acid called N-acetylcysteine [NAC].

NAC protects us in many ways, but, above all, it’s the lung’s guardian, and since our lungs are so vulnerable to free radicals in this polluted world, I believe this is a nutrient crucial to general health — a nutraceutical many of us could benefit from.

Defend With NAC

The chemical interactions between our body and the environment are part of a grand but precarious balance. Free radicals belong in this category. Think of these electron radicals darting through our bodies like quasars, or comets.

In a finely tuned system, free radicals are necessary intermediaries of our body’s defence system, created from the very air we breathe and used to power the enormous undertaking of life itself. Rebalancing the body’s free radical scavengers with natural antioxidants like NAC allows us to harness the wilful energy of free radicals for our own healthy advantage.

Dosages are generally from 500-2,000mg, daily, for conditions such as asthma or bronchitis. Patients with serious liver disease or HIV infection take between 1,000-2,000mg per day. For maintenance doses in healthy individuals, 50-100mg should be adequate.

Since NAC is a powerful antioxidant it works synergistically with other vitamins, such as vitamin C, selenium, and lipoic acid.


The novel coronavirus disease [COVID-19] is caused by a virus [SARS-Cov-2] and is known for inducing multisystem organ dysfunction associated with significant morbidity and mortality. Current therapeutic strategies for COVID-19 have failed to effectively reduce mortality rate, especially for elderly patients. As a result, exploring new applications of existing medications could potentially provide valuable treatments for COVID-19. N-acetylcysteine [NAC] has been used in clinical practice to treat critically ill septic patients, and, more recently, for COVID-19 patients. NAC has antioxidant, anti-inflammatory and immune-modulating characteristics that may prove beneficial in the treatment and prevention of SARS-Cov-2.

N-acetylcysteine [NAC] is inexpensive, has very low toxicity, has been FDA approved for many years, and has the potential to improve therapeutic strategies for COVID-19. NAC administered intravenously, orally, or inhaled, may suppress SARS-CoV-2 replication and may improve outcomes, if used timely. Potential therapeutic benefits of NAC include, extracellularly scavenging reactive oxygen species [ROS] radicals, replenishing intracellular glutathione [GSH], suppression of cytokine storm, and T-cell protection, thus mitigating inflammation and tissue injury. NAC administration in combination with other antiviral agents may dramatically reduce hospital admission rate, mechanical ventilation and mortality.

  • Zhongcheng Shi, and Carlos A Puyo, “N-Acetylcysteine to Combat COVID-19: An Evidence Review,” Therapeutics and Clinical Risk Management; 2020; 16: 1047-1055.
Dr RICHARD FIRSHEIN, DO, is the Founder-Director of The Firshein Center for Comprehensive Medicine in New York City. He is a leading innovator and authority in the field of preventative and nutritional medicine, integrating Western and Eastern medical practices. He is Board Certified in Family Medicine and has served as professor of family medicine. An internationally recognised leader in the field of integrative medicine and healthy aging, a cancer researcher, prolific author and writer, Dr Firshein has written several ground-breaking books, including the bestselling Reversing AsthmaYour Asthma-Free ChildThe Nutraceutical Revolution and The Vitamin Prescription [For Life]. This article is ©Dr Richard Firshein.

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