Suppplements containg N-acetylcysteine as an antioxidant supposedly aid muscle recovery. Now it looks like they actually do the exact opposite.
In case you haven’t yet heard about this supplement wonder, N-acetylcysteine (NAC) is a modified form of the amino acid cysteine, which, when given as a supplement, is thought to help the body make the antioxidant enzyme glutathione.
This effect has been used to treat chronic bronchopulmonary disease, to alleviate toxicity of chemotherapy, help people with weakened immune systems due to HIV and to treat acetaminophen (Tylenol) overdose. The rate of success between each of these varies, but at least some look promising.
However, for many users the magic is all in the word “antioxidant” and they buy NAC despite not suffering from any of the above ailments. But then again you could probably also shred old tires, press them in pill form and sell them with a nice profit, as long you put “antioxidant” on the bottle.
Bodybuilders discovered NAC already more than ten years ago, praising its ability to let them supposedly recover faster. Bodybuilding.com, home of reliable bodybuilding information and to a vast online supplement store, naturally wasn’t shy to pick up on that and have one of their “experts” recommend it:
Naturally training athletes can benefit from supplemental use of NAC because of its ability to protect the immune system from harmful oxidants that result from environmental pollution, regular metabolic functions and intense exercise.
Since then, similar statements have been made on the various other bodybuilding websites and forums out there, with many interpretations echoing the “helps you recover faster.” Nobody, it seemed, had much incentive to ask if there was anything more than anecdotal evidence or articles that had to be taken at face value.
This makes a recent piece of research I came across especially interesting. Because it delivers real evidence that comes to a much different conclusion:
Although thiol-based antioxidant supplementation enhances [glutathione] availability in skeletal muscle, it disrupts the skeletal muscle inflammatory response and repair capability, potentially because of a blunted activation of redox-sensitive signaling pathways.
Let me translate this: the muscles of athletes who used NAC didn’t fully recover and their performance got worse. The antioxidant ability of NAC did the exact opposite of what was supposed to happen.
No Surprise, Really
Feel free to believe in N-acetylcysteine letting you recover faster or even making your muscles bigger, but if you want me to believe it, point me at some evidence that is at least as reliable as what I linked above.
Given this current and the previous research about the usefulness of multivitamin supplements and antioxidants, it seems increasingly so that the best thing to do to recover is to simply give your body rest and carry on with a balanced nutrition as usual.
Picture courtesy of “worak“.