top of page
Search

The Chemistry Behind Methanol Intoxication

Did you know that ethanol, also known as ethyl alcohol (C2H5OH), is the psychoactive compound present in beer, wine, and spirits consumed globally?


It is produced by yeast-mediated fermentation of sugars and plays a significant role in social and cultural practices. Although ethanol intoxication primarily impairs the central nervous system, its metabolic processing in humans is comparatively safe. Alcohol dehydrogenase (ADH) converts ethanol to acetaldehyde, which is rapidly metabolized to acetic acid, preventing the accumulation of toxic byproducts. This metabolic pathway distinguishes ethanol as a consumable substance, in contrast to the highly toxic single-carbon alcohol, methanol.


Figure 01 - Comparison of molecules - Available at: https://rayeneh.com/wp-content/uploads/2020/09/ethanol-methanol.png 
Figure 01 - Comparison of molecules - Available at: https://rayeneh.com/wp-content/uploads/2020/09/ethanol-methanol.png 

Methanol, or methyl alcohol (CH3OH), is present in small quantities in various natural and industrial contexts. Historically termed ‘wood alcohol’ due to its production from wood distillation, methanol occurs naturally in many products and ecosystems. Trace amounts are generated in the human digestive system during the breakdown of pectin, a polysaccharide abundant in fruits such as apples and grapes. In addition to its widespread industrial applications, including use as a fuel additive and solvent, methanol is released into the atmosphere by vegetation during metabolic processes. At low, naturally occurring concentrations, methanol does not pose a toxicological risk. 


How does it happen?


Significant risk emerges when methanol is intentionally added to alcoholic beverages for illicit economic benefit. A prominent example is the adulteration of artisanal or counterfeit spirits in São Paulo, Brazil. Producers may replace or supplement potable ethanol with less expensive industrial-grade methanol to reduce costs and increase product volume, often targeting low-cost liquors such as Cachaça and locally bottled whiskey. This practice converts otherwise safe beverages into toxic products, resulting in sporadic but severe methanol poisoning outbreaks among consumers seeking affordable alcohol. Consequently, methanol adulteration constitutes a major regional toxicology concern.


Methanol’s lethality results from its toxic metabolites rather than the parent compound. In the human liver, alcohol dehydrogenase (ADH) metabolizes methanol to formaldehyde (CH2O), which is subsequently converted by aldehyde dehydrogenase to formic acid (HCOOH), a highly toxic substance.


How was it supposed to happen?


ree


Formic acid is the principal toxic agent produced from methanol metabolism. It inhibits cytochrome oxidase, resulting in cellular hypoxia and severe metabolic acidosis. The most characteristic clinical manifestation is irreversible blindness, due to the optic nerve’s heightened vulnerability to formic acid. Without prompt treatment, toxicity can progress rapidly to renal failure, severe neurological damage, and death.


Economic incentives primarily drive the illicit adulteration of alcoholic beverages. Regulatory controls and taxation increase the cost of producing and selling legitimate ethanol for producers and retailers. In contrast, industrial-grade methanol is less expensive, widely available, and often not subject to the same taxes as potable spirits. Illicit manufacturers substitute ethanol with methanol to significantly reduce production costs and increase profit margins, as methanol closely mimics ethanol in appearance and taste to untrained consumers. This practice poses a substantial public health risk for minimal financial benefit.


Figure 03 - Quality control over beverages - Available at: https://media.smallbiztrends.com/2023/11/how-to-start-a-beverage-company-5.png 
Figure 03 - Quality control over beverages - Available at: https://media.smallbiztrends.com/2023/11/how-to-start-a-beverage-company-5.png 

Although methanol poisoning is highly toxic, it is treatable if identified and managed promptly. The primary therapeutic approach is inhibition of alcohol dehydrogenase (ADH) to prevent the formation of formic acid. This is achieved using Fomepizole, a specific competitive inhibitor, or, in resource-limited settings, high doses of ethanol, which competes for ADH. In cases of illicit poisoning, delayed diagnosis or presentation often results in patients reaching critical levels of toxic metabolites, leading to irreversible injury or death. Delayed or inaccessible treatment is therefore associated with poor outcomes.


Conclusion


In summary, methanol poisoning exemplifies a significant chemical and societal hazard in contrast to the relative safety of ethanol consumption. Replacing an ethyl group with a methyl group converts a common beverage ingredient into a potent systemic toxin. This public health threat, driven by economically motivated adulteration, necessitates stringent regulatory oversight and heightened clinical vigilance. A comprehensive understanding of methanol metabolism is essential for preventing the morbidity and mortality associated with this avoidable toxic exposure.


References



Comments

Contact Us!
or email us @veritasnewspaperorg.gmail.com

Thanks for submitting! We will contact you via email - make sure to check your spam folder as our emails sometimes appear there.

veritas.pdf (1).png

© 2025 by Veritas Newspaper

bottom of page