N-Acetyl Cysteine (NAC): Best Supplement For High-Intensity Exercise

N-acetyl cysteine (NAC) is the building block of your body’s most important internal antioxidant. If you like intense exercise, you may want to consider supplementing with it. But hurry, because it might not be available for purchase much longer.

Hey all you Crossfitters, Ironmen and Ironwomen, Tough Mudders, marathon runners and all others out there whose raison d’etre is high intensity exercise.

If you’re not taking the supplement NAC (N-acetyl cysteine), you may want to consider taking it. That’s because intense exercise is a major stressor. The human body does not distinguish between different forms of stress; your brain does not process intense exercise as a form of eustress, or positive stress. 

NAC Supplement For Exercise Recovery

In light of this, high-intensity exercise has the potential to create lots of free-radical cellular damage. NAC, the synthetic form of the amino acid, L-cysteine, is perhaps the most potent supplement for keeping free-radicals in check. 

A precursor to glutathione—commonly called the body’s master internal antioxidant—NAC replenishes glutathione, which is composed of three amino acids: cysteine, glutamic acid, and glycine. 

Glutathione, in addition to acting as the body’s master antioxidant and free-radical scavenger also plays a vital role in the detoxification pathways of the body. It reacts with potentially-harmful chemicals and renders them inert, making NAC one of the best supplements to prevent oxidative damage, a prime premature-aging factor. 

But why not just skip the middleman and take a glutathione supplement? Well, you can take a glutathione supplement, however, many of them, according to PubChem, are “not orally bioactive, and that very little of oral glutathione tablets or capsules is actually absorbed by the body.”

That’s why you may want to consider taking a NAC supplement. Even if you get plenty of rest and eat a very healthy diet, the free-radical damage from frequent intense exercise may weaken your immune system and lead to premature aging. 

Is the FDA Banning NAC Supplements?

High-intensity exercisers aren’t the only population who may benefit from taking a NAC supplement. NAC is unique in that it’s also considered a drug. It has been used since at least the early 1960s as a mucolytic agent (which thins the mucus). People with Cystic Fibrosis (CF) use NAC to clear clogged respiratory passages. The FDA approved NAC as a drug ingredient in 1985, according to Natural Products Insider.

In addition, NAC is used in emergency care settings to treat acetaminophen (Tylenol) overdose.  

If NAC may help support respiratory health for those with CF, may it help the general population in this capacity as well? 

Over the last year or so, some naturopathic doctors, functional medicine doctors and other health professionals that recommend supplements in their treatment protocols, have recommended NAC for the prevention or early-stage treatment of COVID-19. 

Meanwhile, the FDA (as well as the Federal Trade Commission) has sent dozens of warning letters to supplement companies. These letters indicate that the agency, after more than five decades of allowing more than 1,500 supplements that contain NAC on the market, seems to be taking a stance that NAC is a pharmaceutical ingredient. 

The effects of these warning letters are already being felt. Amazon, the world’s largest online retailer, voluntarily removed all NAC supplements in May. 

For now, the FDA has mostly come after NAC-supplement sellers that have made claims that the ingredient is a hangover remedy. 

However, because NAC is currently in clinical trials for COVID-19 infection, supplement industry analysts believe that, should the trials show efficacy, NAC could become monopolized by a drug company. If this scenario comes to fruition, this could eventually lead to the ingredient being pulled from the market as a supplement. 

So in the meantime, if you’re a hardcore exerciser, you may want to buy NAC while you can. 

Natural Sources of NAC

But suppose by the time you read this, NAC is removed by the FDA as a dietary supplement. What then? The good news is that berries are an excellent natural source of the amino acid, cysteine. You can also consume sources of collagen protein such as collagen powder and bone broth, both of which are high in cysteine and glutamate, the two amino acids which synthesize glutathione. 

Do you take NAC for workout recovery or all-around health? Leave a comment below.