What’s the Difference Between Acetaminophen and Ibuprofen?

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Two of the most common pain medications and fever reducers are acetaminophen and ibuprofen. Typically available over the counter, acetaminophen is sold in the United States as Tylenol, and is an ingredient in the products Excedrin and Nyquil. Ibuprofen is the active ingredient in Advil and Motrin, among others. These medications temporarily relieve pain due to headaches, muscle aches, toothaches, and the common cold, among other conditions.

Still, there are some significant differences between acetaminophen and ibuprofen. This article provides an overview of how each drug works and compares what they do, their maximum dosages, safety information, and when you might choose one over the other.     

Close-up view of a hand holding two white pills in the palm above a blurry background

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Ibuprofen was developed in 1961 by a United Kingdom–based pharmacologist and researcher. It belongs to a class of medications known as nonsteroidal anti-inflammatory drugs (NSAIDs). Ibuprofen has been available in the United States since 1974 and is one of the most common analgesic (pain relieving) and antipyretic (fever-reducing) drugs.

Brand Names of Ibuprofen

Ibuprofen is sold under many brand names in the United States, including:

  • Addaprin
  • Advil
  • Cedaprin
  • I-Prin
  • Motrin
  • NeoProfen
  • Proprinol
  • Ultraprin

How It Works

Like other NSAIDs, ibuprofen has an anti-inflammatory effect and works by calming down your immune system’s response to injury or infection (inflammation). Specifically, it stops cells from producing prostaglandin, a chemical compound that causes inflammation, by inhibiting the activity of two enzymes: cyclooxygenase (COX) 1 and 2. The pain-relieving and fever-reducing effects take effect as the inflammation is reduced.


Ibuprofen provides temporary relief from minor aches and pains due to various conditions, including the following:

  • Headache
  • Backache
  • Muscle pain
  • Minor arthritis pain
  • Common cold
  • Toothache
  • Premenstrual and menstrual cramps  

Maximum Dosage

As with any medication, it’s important to use ibuprofen only as directed. Taking too much increases the chances of adverse effects, such as stroke or heart attack, and can lead to bleeding in the stomach.

Maximum daily doses depend on whether you take prescription-strength ibuprofen or over-the-counter (OTC) varieties. The maximum daily dosage for OTC ibuprofen is 3,200 milligrams (mg) for adults and teenagers; maximum doses for younger children depend on body weight.  

Ibuprofen has different strengths, so read the label carefully and ask your provider if you have any questions.  


Though it was first discovered in 1889, it wasn’t until 1956 that acetaminophen was used in a clinical setting. Since then, acetaminophen (Tylenol) has become the most prevalent medication worldwide. Unlike ibuprofen, acetaminophen isn’t an NSAID but is an analgesic and antipyretic.    

Brand Names of Acetaminophen

Acetaminophen is a part of combination OTC products sold under several names. Common brand names of medications that can contain acetaminophen include:

  • Tylenol
  • Tylenol Extra Strength
  • Aceta
  • NyQuil/DayQuil
  • Excedrin
  • Robitussin
  • Mucinex

How It Works

Researchers debate the drug's exact mechanism of action because the way it is metabolized (digested) by the body is complex. Some believe it inhibits the production of COX 1 and COX 2 enzymes by cells, like ibuprofen. This reduces inflammation.

However, some research points to a more direct mechanism. It's thought that acetaminophen acts on two receptors of the areas of the brain responsible for information transmission (midbrain) and (medulla ). These receptors are associated with pain processing in the brain.


OTC acetaminophen is indicated to reduce fever and treat minor pain and discomfort associated with:

Maximum Dosage

Taken at high levels, acetaminophen can damage your liver, which plays a central role in metabolizing drugs you take. The maximum daily dosage of this medication is 3,250 mg for adults and 1,625 mg for children. Severe liver damage can occur if:

  • An adult takes more than 4,000 mg within 24 hours.
  • A child takes the maximum daily dosage of 1,625 mg or more within 24 hours.
  • It is taken alongside other medications that contain acetaminophen.
  • You have more than three alcoholic drinks a day during use.

Notably, acetaminophen comes in different forms and strengths. Double-check your dosage and use any medications only as directed. If you’ve taken more than the recommended maximum amount, get medical help immediately.

What Is the Safest Pain Reliever to Use?

Ibuprofen and acetaminophen are considered safe for most people when taken correctly. However, several factors may make taking ibuprofen unsafe, including:

For acetaminophen, the most significant risk is the potential effect on the liver. As such, liver cirrhosis or liver disease can make taking it more dangerous, and you should steer clear if you know you’re allergic.

Acetaminophen Side Effects

As with other drugs, there are some side effects associated with acetaminophen. The most common of these are:

  • Nausea
  • Vomiting
  • Insomnia
  • Headache

In addition, if you’re allergic to acetaminophen, taking it can cause anaphylactic shock, a medical emergency. Signs of this include:

  • Red, peeling, or blistering skin
  • Rash
  • Itching
  • Hives
  • Difficulty swallowing and breathing
  • Tightness in the chest
  • Swelling in the throat, face, lips, tongue, hands, eyes, feet, ankles, or legs

Ibuprofen Side Effects

Ibuprofen also can cause some adverse effects. Common side effects include:

  • Headache
  • Nausea
  • Feeling dizzy or faint
  • Vomiting
  • Indigestion
  • Constipation
  • Diarrhea
  • Flatulence or gas

In addition, there are several serious side effects. Call 911 if you experience:

  • Severe chest or stomach pain
  • Black-colored stool
  • Blood or a black tarry substance in your vomit
  • Swelling in the ankles
  • Tightness in the chest
  • Severe headache and neck stiffness
  • Aversion to bright lights
  • Blurred vision
  • Signs of allergic shock

Which Is Worse for Your Liver: Tylenol or Ibuprofen?

While low doses are harmless, in high amounts, acetaminophen can impact liver function and lead to liver failure. It has been linked to nearly half of overdose-related acute liver failure cases in the United States.

Which Is Worse for Your Stomach?

Too much ibuprofen can damage and erode the stomach lining, causing ulcers and bleeding. Compared to acetaminophen, it’s much tougher on this body part. Compared to acetaminophen, ibuprofen may be more damaging to the kidneys.

When to Use Ibuprofen vs. Acetaminophen

Ibuprofen is effective for pain and inflammation. In contrast, acetaminophen acts on pain processing in the brain; both reduce fever. Which is better for pain and headaches related to the common cold, flu, or fever is subject to individual preference.

That said, ibuprofen may be better for conditions that involve swelling and inflammation, like arthritis, muscular pain, injury to the body, or menstrual cramps. Since acetaminophen is not an anti-inflammatory drug, it won’t be as effective.  


Acetaminophen (Tylenol) and ibuprofen (Advil) are two of the most common pain-relieving medications and fever reducers. Ibuprofen is a pain reliever and an anti-inflammatory drug, whereas acetaminophen acts on pain. Though both are safe for most when taken as directed, adverse effects can arise with acetaminophen and ibuprofen overuse.

Frequently Asked Questions

  • Can you take ibuprofen and acetaminophen together?

    Since ibuprofen and acetaminophen are different classes of drugs, they can safely be taken together. There may be a benefit if the two are taken together. In 2020, the Food and Drug Administration (FDA) approved an over-the-counter combination drug called Dual Action.

  • Which is stronger, Advil or Tylenol?

    Advil and Tylenol are effective for mild pain. However, some research has found Advil to be more effective than Tylenol. In a wide-ranging review comparing the two, ibuprofen was typically more effective than its counterpart (acetaminophen) for various pain conditions.

  • Why shouldn’t you lie down after taking acetaminophen?

    After taking acetaminophen, the medication must reach your digestive system. Stay upright immediately after taking the medication to make sure the it makes it to your stomach. When lying down immediately after taking the tablets, they can become lodged in your throat, breaking down before they are properly ingested. This can also damage your esophagus (food tube) and cause irritation.

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Mark Gurarie
Mark Gurarie is a freelance writer, editor, and adjunct lecturer of writing composition at George Washington University.