Denatured Alcohol vs. Isopropyl Alcohol: A Detailed Comparison

Alcohol is in a lot of different products, but is it the same alcohol that we drink? Not exactly. Only one type of alcohol is safe for human consumption — ethanol. And from what we know about drinking alcohol, “safe” isn’t necessarily a quality descriptor. 

To help us distinguish between the different types of alcohol, let’s walk through an in-depth comparison of two common types of alcohol — denatured alcohol and isopropyl alcohol. We’ll also explore how the two differ from ethanol and how we can approach each safely.

Understanding Denatured Alcohol

Let’s start by breaking down denatured alcohol. What is it? How is it made? Is it safe to drink? A few simple math equations can help us better understand. 

Plants + Fermentation = Ethanol

Ethanol, also known as ethyl alcohol, is a clear, colorless liquid produced by the fermentation of different plants. Yeast converts the sugar and starches into cellular energy. In the meantime, carbon dioxide and ethanol are produced as byproducts. 

Ethanol is used for alcoholic beverages and causes intoxication. Aside from alcoholic beverages, ethanol is used within the food industry as a solvent, preservative, and flavor enhancer. Ethanol’s versatility extends beyond food and beverage. The inclusion of additives categorizes it as denatured alcohol. 

Ethanol + Denaturants = Denatured Alcohol

Denatured alcohol falls under the broad category of ethanol but belongs to its own distinct group. It’s a mix of ethanol with other chemicals known as denaturants. Denaturants are toxic chemicals unfit for human consumption. The addition of denaturants differentiates denatured alcohol from consumable ethanol, allowing manufacturers to get around federal excise taxes that regulate ethanol (alcoholic beverages). 

Denatured Alcohol + Human Consumption = Danger

While ethanol and denatured alcohol are commonly used interchangeably, it’s important to note that all denatured alcohol contains ethanol, but not all ethanol is considered denatured alcohol. The main difference between ethanol and denatured alcohol is that ethanol is made for human consumption and denatured alcohol is not. Consuming denatured alcohol can cause many reactions, from nausea and vomiting to respiratory failure and metabolic acidosis. It is critical to seek medical attention if you or someone you know ingests denatured alcohol.

Understanding Isopropyl Alcohol

Now that we have a better understanding of denatured alcohol, let’s take a closer look at isopropyl. 

Water + Propene = Isopropyl Alcohol

Isopropyl alcohol is a synthetic chemical that is commonly produced by combining water and propene (gas produced from fossil fuel) through a process called hydration. It has various uses but is most commonly used as a disinfectant. 

Isopropyl Alcohol + Human Consumption = Danger

Like denatured alcohol, isopropyl alcohol is not meant for human consumption. Ingesting isopropyl can lead to problems ranging from irritation to respiratory distress to hypoglycemia. If you or someone you know ingests isopropyl, seek medical attention immediately. 

Now that we understand the inner workings of both denatured alcohol and isopropyl, let’s compare the two.

Isopropyl vs. Denatured Alcohol: What’s the Difference?

Denatured alcohol and isopropyl alcohol are similar in the way they’re used but differ chemically. There are many additives commonly found in denatured alcohol that aren’t in isopropyl alcohol.

• Methanol
• Gasoline
• Benzene
• Pyridine
• Castor oil
• Acetone

Chemicals that are added to denatured alcohol are extremely toxic when ingested. Specifically, methanol, which is found in many household and industrial products, is poisonous and can cause death when consumed. For this reason, the applications of denatured alcohol and isopropyl alcohol vary somewhat.

Applications

Isopropyl alcohol is used in everyday products that can come in contact with our skin. It’s not meant to be consumed, although it is less toxic than denatured alcohol. (As it’s used in disinfectants, isopropyl alcohol is commonly labeled “rubbing alcohol.”) Among the applications for denatured alcohol and isopropyl alcohol are:

• Disinfectants. Denatured (ethyl) alcohol and isopropyl alcohol are FDA-approved bases for hand sanitizers. They are also used in other disinfectant products due to their antibacterial properties. 
• Fuels. Both alcohols are also found in fuels, although denatured alcohol is often preferred to prevent misuse. 
• Cosmetic products. Alcohol is frequently used in the cosmetic industry for different purposes. Denatured and isopropyl alcohol are quality solvents that can be used to mix fragrances and colorants. They can also be used as preservatives and antimicrobials for these products. 
• Household products. Denatured and isopropyl alcohol serve as bases for such household products as cleaners, laundry and dishwashing soaps, plastic and rubber products, and more.
• Industrial products. Both alcohols, more so denatured alcohol, are used to create such industrial products as antifreeze, agricultural products, adhesives and sealants, and more.

While denatured and isopropyl alcohol have overlapping applications, their differences in toxicity have led to their use in different kinds of products. For example, isopropyl alcohol is commonly used in household products. Denatured alcohol is used more commonly in industrial products with which we have less contact. Although both alcohols are helpful in many ways, they both have a major drawback — their toxicity. 

Toxicity

Alcohol poisoning, no matter the type, can be extremely dangerous. We briefly covered some of the symptoms before, but let’s dig deeper. 

Isopropyl alcohol poisoning is the leading toxic alcohol ingestion that is reported to the U.S. poison control centers each year. Isopropyl alcohol toxicity is rarely fatal but can lead to coma or other severe symptoms:

• Low blood pressure
• Low body temperature
• Dizziness
• Nausea and vomiting
• Increased heat rate
• Slow breathing
• Decreased reflexes 
• Slurred speech 
• Throat pain
• Loss of consciousness 

Denatured alcohol has additives that make it specifically unsafe for human consumption. Even minimal amounts can be extremely toxic and lead to death. One study on mice reported that all mice that were administered denatured alcohol intraperitoneally (within the abdominal cavity) died within 24 hours. 

In humans, denatured alcohol poisoning is often fatal and may include many severe symptoms.

• Nausea and vomiting 
• Seizures
• Visual disturbances 
• Abdominal pain
• Trouble breathing
• Loss of consciousness 

If denatured alcohol or isopropyl alcohol is accidentally consumed, call Poison Control immediately at 1-800-222-1222 for guidance on how to proceed. Dial 911 if you notice any of the symptoms above or other serious signs. 

What Does This Tell Us About Ethanol?

Ethanol is distinct from denatured and isopropyl alcohol, and it is labeled as safe for human consumption. However, the high toxicity of denatured and isopropyl alcohol gives us some insight into how harmful ethanol can be. 

Although ethanol is safe for consumption, it can still have harmful effects. When we drink, ethanol enters our bloodstream, targets our central nervous system (CNS), and slows down messaging from our brain to the rest of our body. This action affects normal functions such as thinking, judgment, and motor control. When we drink, ethanol also begins to break down into a toxic compound called acetaldehyde, which is classified as a carcinogen. Prolonged and excessive exposure to the toxins in ethanol can lead to long-term health conditions:

• Liver disease
• Risk of cardiovascular disease
• Risk of cancer
• Pancreatitis 
• Gastrointestinal problems 

For a seemingly “safe” substance, it’s associated with surprisingly severe health issues. In fact, long-term health conditions remain the leading cause of alcohol-related mortalities. While ethanol is regarded as “safe” for human consumption, excessive drinking causes more than 178,000 deaths in the U.S. yearly, according to the Centers for Disease Control and Prevention (CDC). Understanding the toxicity of different types of alcohol helps us see that ethanol may not be so safe after all. 

Actionable Tips

Boiling It Down

Denatured alcohol and isopropyl alcohol are two types of alcohol that are similar in a number of ways. While alike in application, the two have different toxicity levels, which have led to their use in different kinds of products. Denatured and isopropyl alcohol alsp are different from ethanol — more specifically, the alcoholic beverages we drink — due to additives that make them unsafe for human consumption. However, ethanol still has detrimental effects on our health. Labeled as “safe,” ethanol walks a fine line between toxic and not. Whether you’re using denatured, isopropyl, or ethanol, it’s best to follow protocol!