Motrin (ibuprofen) is the stronger fever reducer. In head-to-head studies, ibuprofen lowered fevers more effectively than acetaminophen (Tylenol) at 2, 4, and 6 hours after a dose. But “better” depends on your health situation, because each drug carries different risks, and Tylenol is the safer choice for certain people.
How Much Better Is Motrin at Lowering Fever?
A meta-analysis published in The Journal of Pediatrics compared standard doses of both drugs across nine fever trials involving over 1,000 children. Ibuprofen reduced temperature more than acetaminophen at every time point measured. The difference was modest at the two-hour mark but grew larger by four and six hours, meaning ibuprofen not only brings a fever down further but holds it down longer.
At a higher dose of ibuprofen (10 mg/kg), the gap widened considerably. The effect size at four hours was roughly four times larger than what was seen at two hours with the lower dose. In practical terms, this means ibuprofen at full dose can produce a noticeably greater temperature drop than acetaminophen at full dose.
Both drugs work partly by blocking an enzyme that produces a fever-triggering chemical in the brain. Ibuprofen also reduces inflammation throughout the body, which gives it an edge when a fever is driven by an inflammatory illness like an ear infection or sore throat. Tylenol works almost entirely in the brain’s temperature-control center, which makes it effective but less powerful overall.
How Long Each Drug Lasts
Tylenol’s fever-lowering effect typically lasts 4 to 6 hours per dose, and you can take it every 4 hours (up to 5 doses per day for children, with a daily maximum of 4,000 mg for adults). Motrin lasts 6 to 8 hours per dose and is taken every 6 to 8 hours. That longer window means fewer doses through the day and more uninterrupted sleep at night, which matters a lot when you’re sick.
When Tylenol Is the Better Choice
Despite ibuprofen’s edge in raw fever reduction, Tylenol is preferred in several situations where ibuprofen poses real risks.
- Stomach problems. Ibuprofen can cause bleeding in the stomach or intestines, sometimes without warning symptoms. If you have a history of ulcers, regularly drink alcohol, smoke, or are over 60, Tylenol is gentler on the digestive tract.
- Heart disease or high blood pressure. Ibuprofen may increase the risk of heart attack, heart failure, or stroke, especially in people who already have cardiovascular disease. Tylenol does not carry this risk.
- Kidney disease. Ibuprofen can worsen kidney function, particularly in people who are dehydrated from a fever-related illness. Tylenol is processed by the liver, not the kidneys.
- Asthma triggered by aspirin. People with aspirin-sensitive asthma should avoid ibuprofen entirely, as it works through the same pathway and can trigger bronchospasm. Tylenol is safe for this group.
- Pregnancy. Acetaminophen has traditionally been the go-to pain and fever reliever during pregnancy, though recent research has raised questions about potential associations with neurological conditions in children when taken chronically throughout pregnancy. Ibuprofen is generally avoided during pregnancy, particularly in the third trimester. Low-grade fevers during pregnancy often don’t require medication at all.
When Motrin Is the Better Choice
If you don’t fall into any of the risk categories above, ibuprofen is the stronger option for bringing down a fever. It’s particularly useful when fever is accompanied by body aches, joint pain, or visible inflammation, since it tackles both the fever and the underlying inflammation driving it. For someone with a healthy stomach, normal kidney function, and no heart concerns, ibuprofen offers more fever relief per dose and longer coverage between doses.
Ibuprofen is also a reasonable first choice for otherwise healthy children over 6 months old who have moderate to high fevers. The meta-analysis data showed consistent superiority in the pediatric population specifically.
Liver Risk With Tylenol
Tylenol’s biggest danger is liver damage from overdose. The maximum safe amount for adults is 4,000 mg in 24 hours, and the real-world risk is higher than most people realize because acetaminophen is hidden in dozens of combination products: cold medicines, sleep aids, and prescription painkillers. Taking Tylenol for a fever while also taking a cold remedy that contains acetaminophen can push you over the limit without you knowing it. Drinking alcohol while taking Tylenol further increases the risk of liver injury.
For children under 12, acetaminophen liquid is dosed by weight (160 mg per 5 mL is the standard concentration). Never exceed 5 doses in 24 hours for children, and always use the measuring device that comes with the product. Children under 2 should not receive acetaminophen without guidance from a pediatrician.
Should You Alternate Both?
Alternating Tylenol and Motrin every few hours is a common practice, especially among parents trying to keep a child’s fever down overnight. But there’s no good evidence that this approach works better than using either drug alone, and it introduces real risk. The American Academy of Family Physicians has cautioned against alternating regimens because the dosing schedule becomes confusing (if one drug is given every 4 hours and the other every 6, which one is due at the 12-hour mark?) and the confusion can lead to accidental overdose.
If one medication isn’t controlling a fever adequately, switching to the other entirely is a simpler and safer strategy than trying to juggle both on overlapping schedules.
The Bottom Line on Choosing
For most healthy adults and children over 6 months, Motrin will bring a fever down more and keep it down longer. Tylenol is the right pick when stomach, kidney, or heart issues are in play, or when you’re already taking other medications that interact with ibuprofen. Either drug is safe and effective at standard doses for short-term fever management. The best one is the one that matches your body’s specific vulnerabilities.