N-Acetyl Cysteine Benefits and Side Effects

n-acetyl cysteine benefits

Here’s one that is a little difficult to say: N-Acetyl Cysteine.  N-Acetyl Cysteine is almost completely synthetic.  It’s not something that you inherently find in your body, but that doesn’t make it dangerous.  N-Acetyl Cysteine comes from an amino acid called L-cysteine.  Traces of L-cysteine ARE found in your body as it is an amino acid and since proteins are comprised of the amino acid, it makes sense that we’d be able to find traces of L-cysteine.  N-Acetyl Cysteine has been formulated to treat a large variety of ailments in humans.  As always, we’ll take a look at the use cases N-Acetyl Cysteine is applied to when it comes to health and fitness [1].

The Fitness Benefits

Bodybuilders and cardio freaks alike both have been known to supplement with N-Acetyl Cysteine.  The reasoning?  Glutathione.  Glutathione is arguably the body’s best antioxidant.  N-Acetyl Cysteine wildly boosts the body’s natural production of Glutathione, which is the primary antioxidant when it comes to defense against muscular fatigue.  The longer we can prevent fatigue from setting in, the more reps we can lift or the more miles we can run.

The Medical Benefits of N-Acetyl Crysteine

As previously mentioned, N-Acetyl Cysteine is used in medications to treat humans for many different things.  The most common diseases and issues treated with medications containing N-Acetyl Cysteine involve the vital organs; Specifically the lungs, kidneys, and heart.  N-Acetyl Cysteine is one of the most common treatments for bronchitis and asthma.  It leads to unclogged airways and improved lung function.  As early as 1998, N-Acetyl Cysteine was found to be a commonly effective treatment for various poisonings, protecting the kidneys from extensive damage [2].  Treatments aren’t always physical.  Psychiatrists have been prescribing patients with N-Acetyl Cysteine based medications to help deter Alzheimer disease [3].

N-Acetyl Crystein Side Effects

Most people don’t see any negative side effects when they supplement N-Acetyl Cysteine.  The key is that you supplement responsibly, never ingesting more than the suggested serving amount.  N-Acetyl Cysteine comes in tablet form, so it isn’t like you’re going to need to do any measuring or worry about blending a specific amount in your protein shake.

If you DO happen to take a little too much, the most common side effects seem to be all the “regulars.”  Nausea, vomiting, diarrhea, fever, headaches, and liver issues.  I say “regulars” because if you ingest too much of most supplements, those are the common side effects [4].  In the more rare and extreme cases, you can experience rash, drowsiness, chest tightness, and low blood pressure.  If you start to experience any of these side effects, contact your physician as it’s possible your body is having some sort of negative reaction to the N-Acetyl Cysteine.

N-Acetyl Cysteine should not be self-prescribed for asthma treatment.  N-Acetyl Cysteine might slow blood clotting so if you have an iron deficiency or bleeding disorder, you need to be more cautious while supplementing.  N-Acetyl Cysteine has NOT been found to be harmful to pregnancy.


  1. Vida Mokhtari, M.Sc,1,2,3 Parvaneh Afsharian, Ph.D,2 Maryam Shahhoseini, Ph.D,2 Seyed Mehdi Kalantar, Ph.D,1 and Ashraf Moini, M.D3,4,*
    A Review on Various Uses of N-Acetyl Cysteine
    Cell J. 2017 Apr-Jun; 19(1): 11–17. Published online 2016 Dec 21. doi: 10.22074/cellj.2016.4872
  2. Kelly GS1.
    Clinical applications of N-acetylcysteine.
    Altern Med Rev. 1998 Apr;3(2):114-27.
  3. Olivia Dean, BSc, PhD, Frank Giorlando, MBBS, BMedSc, and Michael Berk, MBBCh, MMed(Psych), PhD
    N-acetylcysteine in psychiatry: current therapeutic evidence and potential mechanisms of action
    J Psychiatry Neurosci. 2011 Mar; 36(2): 78–86. doi: 10.1503/jpn.100057
  4. Flanagan RJ1, Meredith TJ.
    Use of N-acetylcysteine in clinical toxicology.
    Am J Med. 1991 Sep 30;91(3C):131S-139S.
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