N-acetyl cysteine, also written as N-acetylcysteine or simply NAC, is a compound produced in the body from cysteine, a non-essential amino acid. It is utilized to synthesize glutathione, another amino acid involved in the detoxification of carcinogens. While these chemicals work together synergistically to keep the body free of foreign materials, n-acetyl cysteine is a potent antioxidant on its own. In fact, it plays a key role in the neutralization of reactive oxygen molecules and other free radicals.
When administered as an inhalant, this compound may provide relief for many respiratory disorders. It is attributed with mucolytic properties, meaning that it acts as a decongestant to help loosen and literally digest mucus in the lungs. This is accomplished by dissolving certain proteins present in mucus by breaking the “disulfide bridge,” or the covalent bonds that link their thiol groups. Several clinical trials demonstrate this activity, making this substance a valuable treatment for chronic bronchitis, pneumonia, tuberculosis, emphysema, and chronic obstructive pulmonary disease (COPD).
As a nutritional supplement, n-acetyl cysteine may have a great range of applications due to its regulation of glutathione as well as glutamate, an important neurotransmitter involved in cellular metabolism. While there has not been nearly enough research performed to substantiate the validity of treating many of the conditions this compound is reputed to improve, there is sufficient evidence to warrant further investigation. For instance, there are reports that this agent may be a home remedy for a hangover when combined with vitamins C and B1. Other claims include the ability for this amino acid to temper certain compulsive disorders, especially nail biting and hair pulling. In contrast to this anecdotal evidence, there is clinical evidence to support claims that n-acetyl cysteine improves the symptoms of depression, bipolar disorder, and schizophrenia.
The antioxidant activity of NAC leads researchers to suspect that it may be play a role in the prevention and treatment of cancer. In addition to inhibiting oxidative damage, studies have shown that this acid deters the rate of growth and metastasis of cancer cells. It has also been established that this agent can prevent liver damage caused by acetaminophen poisoning, as well as renal failure caused by radiocontrast-induced nephropathy (RCN). In the case of acetaminophen toxicity, NAC stimulates an increase in glutathione release, which prevents the accumulation of n-acetyl-p-benzoquinone imine, a by-product of acetaminophen metabolism that damages liver cells.
There are several ways in which n-acetyl cysteine may be administered. It is available in liquid form and as effervescent tablets in most countries without a prescription. When used to counter acetaminophen overdose, it is given via intravenous injection. When used in mucolytic therapy to relieve lung congestion, it may be given as an ocular or inhalant solution, either of which usually requires a prescription.