NAC and Your Aging Brain

February 20, 2022

NAC and Your Brain

NAC, N-acetyl cysteine, is one of the most studied supplements today. PUBMED registers some 900 citations a year on it. You should know about NAC too because it has a huge benefit on the aging brain. There is some controversy about what its exact mechanism of benefit is, because it has demonstrated so many benefits in so many clinical settings, but the most commonly stated one is that it increases your natural glutathione level. Glutathione is the antioxidant that your body makes to protect itself against oxidation. As we age, we make less.

Our backup antioxidant system in our central nervous system is the vinyl ether bond on plasmalogens, and the loss of glutathione results in scavenging plasmalogen lipids in the brain, leading to a spiral of decline. Folks with cognitive issues have demonstrated less glutathione in their brains. Parkinson's disease is also known to have lower levels of glutathione in the substantial nigra, and IV glutathione has been shown to assist Parkinson's patients to some degree. The Michael Fox Parkinson's website has a nice review of it.

NAC has been around since the 1960s when it was first discovered and introduced for the treatment of acetaminophen (Tylenol) overdoses. It halted liver failure overnight when given within 10 hours of ingestion. Over the years, the use of NAC changed from IV administration in the ICU, to IV in the hospital, to IV in the ER, to oral administration in the ER, to outpatient oral administration, and finally, to release as an over-the-counter supplement.  It has a remarkable record of safety.  Then, in mid-2021, the FDA got a bee in its bonnet and decided to withdraw it as a safe supplement, despite there being no sign of toxicity. It was a technicality of regulations. "Not a lawful dietary ingredient per the FD&C Act’s drug-exclusion clause because the ingredient was first authorized for investigation as a new drug before it was marketed as a dietary supplement." A legal action by various citizen advocacy groups has brought it back on the market pending review.

What's the normal person to do? Well, we do know that NAC protects you from Tylenol toxicity. That is solid. If you are on Tylenol chronically for pain control, the addition of NAC will likely protect you from liver damage. This is no small deal. Chronic liver damage from acetaminophen is part of the epidemic of liver failure in America. If you take enough NAC, you are completely protected.

We do know it raises your glutathione level, if you are low. It has not been shown to elevate levels above normal glutathione. Folks with normal levels of glutathione don't benefit. That includes anyone under age 20. But as we age, so many of us are low that it probably plays a beneficial role in just about everyone over age 60. It is not super well absorbed orally. Only about 10% of an oral dose gets into you so any dose below 1,200 mg is likely not helpful by much. There are indications that 2 grams (2,000 mg) to 4 grams might be what it takes to help lower homocysteine levels. Homocysteine is a marker of methylation stress and correlates with cognitive decline and myocardial infarction risk. Adding NAC to your armamentarium against homocysteine works. Again, by some calibrated increase in dosing. (One report of 50% reduction of homocysteine).

There is one case report of a Tylenol overdose being given 100 grams of NAC IV instead of 10 grams by medical error. That event resulted in death from the NAC overdosing. 10 grams would have saved her life.

That's where we are. In limbo. The FDA is thinking about it. NAC has a remarkable safety profile aside from one case. We allow Tylenol and Benadryl to be on the market, two markedly more dangerous supplements.

www.What will Work for me. I'm irritated by the FDA. I smell a rat. There is some pharmaceutical company trying to leverage the FDA into making it back into a prescription drug, at great expense, for needless effect. I sent in a letter to the FDA registering my annoyance. I'm taking it every day. If you are over age 60, you likely should be too. We get older because our glutathione starts to disappear. NAC alters that trajectory. Taking plasmalogens gives your brain another tool to capture oxidizing free radicals, but glutathione is a remarkable compound. When I found that I had a gene deletion for making my own glutathione that resulted in many elevated environmental toxins, I took IV glutathione for 6 months and completely repaired my toxicities. That's how powerful glutathione is. That's how beneficial NAC is, by extension. I smell a rat.

References:   ScienceDirect, Life Extension, FDA, MIchael Fox, Int Med Case Reports, Parkinson's Resource,

Pop Quiz

1. What is NAC?                             Answer:   The altered form of the amino acid cysteine that is the rate-limiting step to you making your own glutathione. Glutathione is your antioxidant of first resort.  When you take NAC, your glutathione rises.

2. NAC has been the cure for what common overdose?                         Answer: Tylenol, the number one oral overdose in America. No one dies if they get to health care within 10 hours.

3. As we age, what happens to our brains with glutathione?                        Answer: It drops precipitously.

4. Is that a problem?                                Answer. Yes, because then our brains depend more on plasmalogens to neutralize oxidizing peroxide radicals, and then we deplete our plasmalogens. That is the engine that drives cognitive decline.

5. NAC is a very dangerous compound and should be carefully regulated. People die from it. T or F?                                   Answer: Yes, one person has died from getting a 10 times IV overdose. Because we only absorb 10% of it when taken orally, that would have required the equivalent of 1 kilogram of oral NAC to be a lethal dose. One kilogram of any drug on the market would be lethal. The right answer is FALSE. It is one of the safest compounds on the market.

This column is written by Dr. John E Whitcomb, MD, Brookfield Longevity, Brookfield, WI. (262-784-5300)