General Description
N-acetyl cysteine (NAC) is a white, crystalline powder derived from
the amino acid cysteine, which serves as a precursor to glutathione,
the body's most abundant antioxidant. Although NAC does not occur
naturally in the diet, it is available as a dietary supplement.
Cysteine, the amino acid from which NAC is derived, is found in
many high-protein foods.
Health Applications
- Bronchitis/lung health
- Angina
- Antioxidant support
Contemporary Uses
The most common medicinal use of N-acetyl cysteine is to help
dissolve mucus in patients with bronchitis or other obstructive
pulmonary diseases. In a survey of general practitioners in the
Netherlands, roughly one third reported prescribing NAC for children
with various pulmonary disorders such as bronchitis and asthmatic
bronchitis.1 Numerous studies have shown NAC
to be effective in preventing exacerbation (worsening) of symptoms
in both chronic and acute bronchitis.2-8 Because
NAC can serve as a glutathione precursor, it is sometimes taken
to improve the body's antioxidant defenses; however, studies indicate
that supplemental NAC does not produce a sustained increase in
serum glutathione levels in healthy people 9
and may even act as a prooxidant in high doses.10
Some studies indicate that NAC can increase the effectiveness
of nitroglycerin in treating angina,11-15
but the high incidence of side effects associated with NAC/nitroglycerin
combination treatment may make it unsuitable for many angina patients.14,15
Dosage/Toxicity
Many of the studies on NAC supplementation in bronchitis patients
have used 600 mg per day.2,5,6 NAC appears
to be well tolerated at this dosage level. Side effects such as
hypotension and severe headaches have been reported in angina
patients taking NAC with nitroglycerin.14,15
Although NAC appears to have very low toxicity, one study indicates
that it may cause oxidative damage at dosages of 1200 mg or more
per day.10 |
