There is a growing body of anecdotal evidence suggesting that ingesting NAC (N-Acetyl Cysteine) can reduce blood acetaldehyde and alleviate the symptoms of alcohol flush reaction and even hangover. The purpose of this article is to look into the science and provide a clear answer on just how effective NAC is in reducing your red face from alcohol.
We start our analysis by looking at a study conduct in 1974 where scientists tested the effectiveness of an oral administration of l-cysteine, thiamin and l-2-methylthiazolidine-4-carboxylic acid in protecting mice against lethal doses of acetaldehyde.
At 2.0 mM/kg, survival after 24–72 hours withl-cysteine free base(FB) was 80%; with l-2-methylthiazolidine-4-carboxylic acid (l-MTCA), 75%; with thiamin·HCl, 90%; and only 10% with saline control. At 0.3 mM/kg, thiamin·HCl gave virtually no protection (13% survival). The combination ofl-cysteine FB plus thiamin·HCl, each at 2.0 mM/kg, gave 100% survival. The oral LD50 dose (Litchfield-Wilcoxon) in mM/kg forl-cysteine FB was 15.6(14.8–16.4); forl-MTCA, 17.9 (17.0–18.8), and for thiamin·HCl, 11.0 (10.4–11.6).
The relevant result here is that the combination of l-cysteine and thiamin at the correct dosage gave a 100% successful in protecting mice against lethal doses of acetaldehyde.
L-cysteine and NAC are closely related amino acids but are not the same thing. That said, both can be used as supplement aids to help your body produce more natural glutathione.
Your body needs glutathione to break down acetaldehyde and as a result, when you drink alcohol your glutathione levels are severely depleted and can sometimes stay that way depending on your alcohol intake.
In this sense, there is some evidence to suggest the role of NAC in helping our body produce sufficient levels of glutathione in order to break down the acetaldehyde we receive when we drink alcohol.
Can NAC also bind to acetaldehyde and reduce alcohol flushing?
In a 1995 study looking at the role of NAC in attenuating alcohol-related hypertension in rats, scientists stated that:
N-acetyl cysteine (NAC), an analogue of the dietary amino acid cysteine, binds acetaldehyde, thus preventing its damaging effect on physiological proteins.
They concluded by saying that:
Increase in blood acetaldehyde with ethanol treatment was significantly attenuated with N-acetyl cysteine treatment.
This study further strengthens the relationship between NAC supplementation and reduced blood acetaldehyde. That said, the research in this case was conducted on lab rats and warrants further testing using human subjects.