Can I take N-Acetylcysteine (NAC) long-term?
Q: I have been taking the N-Acetylcysteine (NAC) product for about a year – 2 pills per day. I am wondering if this should be stopped for awhile and can taking it for too long a period hinder building up my immune system or cause any health problems.
A: NAC is generally well tolerated. The most frequent complaints involve diarrhea, nausea, and vomiting with oral supplementation. There is not a lot of published research on long-term oral use on this supplement in humans, though I do not see any research on it hindering the build up of immune system (i.e. glutathione levels).
Here are some studies:
Long-term N-acetylcysteine and L-arginine administration reduces endothelial activation and systolic blood pressure in hypertensive patients with type 2 diabetes. – this 2008 study is done for 6 months, and the researchers good level of response during this time frame.
Formulation of a medical food cocktail for Alzheimer’s disease: beneficial effects on cognition and neuropathology in a mouse model of the disease. – this 2010 study combined NAC along with other nutrients in a medical food are a safe, effective and natural treatment for Alzheimer’s disease.
Oral N-acetyl-cysteine attenuates loss of dopaminergic terminals in alpha-synuclein overexpressing mice. – this 2010 study is for 1 year, and showed benefit with NAC in reducing the processes that can lead to Parkinson’s disease.
“N-Acetylcysteine for Lung Cancer Prevention“, Van Zandwijk, Nico Chest, May 1995;107(5):1437-1441. (Address: Nico Van Zandwijk, M.D., Ph.D., The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands)
In large groups of patients with chronic obstructive lung disease N- acetylcysteine has turned out to be a safe agent with minor effects even when prescribed for a prolonged period of time. N- acetylcysteine is well tolerated when taken continuously in a dose of 600 mg per day. Dyspepsia has been reported as a mild side effect. N-acetylcysteine holds promise and it may turn out to be effective in preventing secondary tumors. It may have a wider use in chemopreventive purposes.
If you are getting negative gastrointestinal symptoms, it may be best to reduce your dose to 1 capsule of Amino NAC per day rather than 2 caps.