Motrin (ibuprofen) provides pain and fever relief that typically lasts 4 to 6 hours per dose. The drug reaches its peak effect within one to two hours of swallowing a tablet, then gradually tapers off. A single dose is fully cleared from your system in roughly 10 hours.
How Quickly Motrin Starts Working
Most people begin to feel relief within 30 to 60 minutes of taking Motrin. Blood levels of the drug peak at about one to two hours after you swallow a standard tablet. Liquid gel capsules and chewable tablets are absorbed faster, reaching peak levels in roughly 45 to 60 minutes, because they dissolve more quickly in the stomach.
Eating before or alongside your dose slows things down. Food can reduce peak blood levels by 30 to 50 percent and delay the time to reach those levels by 30 to 60 minutes. If you need fast relief, taking Motrin on a relatively empty stomach will get it working sooner, though taking it with food is gentler on the stomach lining.
How Long the Pain Relief Lasts
A single dose of Motrin keeps working for about 4 to 6 hours. That window varies depending on the severity of your pain, your body size, and how quickly your metabolism processes the drug. For mild headaches or muscle aches, one dose may feel effective for closer to 6 hours. For more intense pain, like a toothache or menstrual cramps, you may notice the relief fading closer to the 4-hour mark.
This is why the standard dosing interval is every 6 to 8 hours. You can take your next dose as soon as 6 hours after the previous one if the pain returns, but stretching to every 8 hours is easier on your stomach and kidneys.
How Long It Stays in Your Body
Even after the pain relief wears off, ibuprofen is still being processed. The drug has a half-life of about 1.9 to 2.2 hours, meaning your body eliminates half of the dose roughly every two hours. It takes 4 to 5 half-lives for a drug to be fully cleared, which puts total elimination at approximately 10 hours after your last dose.
This matters if you’re switching to a different pain reliever, preparing for surgery, or concerned about drug interactions. After 10 hours, the ibuprofen from a single dose is essentially gone from your bloodstream.
Adult Dosing and Daily Limits
The standard over-the-counter dose for adults is 200 to 400 mg every 6 to 8 hours. At the 200 mg strength, the maximum is 6 tablets (1,200 mg) in 24 hours. At the 400 mg strength, the limit is 3 tablets (1,200 mg) in the same period. These are the OTC ceilings set for self-treatment of everyday pain and fever.
For chronic conditions like arthritis, doctors sometimes prescribe higher daily amounts, up to 3,200 mg per day split into three or four doses. These prescription-level doses carry greater risk of stomach irritation and other side effects, which is why they require medical supervision. If you’re using Motrin for occasional aches, staying within the OTC limits keeps the risk profile low.
Dosing for Children
Children’s Motrin can be given every 6 to 8 hours, the same interval as the adult version. The dose itself is based on your child’s weight, not age, though age can serve as a rough guide if you don’t have a recent weight. Packaging includes a dosing chart that pairs weight ranges with the correct amount of liquid or number of chewable tablets.
Ibuprofen is not recommended for infants under 6 months old. It hasn’t been established as safe in that age group, and the FDA has not approved its use for them. For babies younger than 6 months, acetaminophen is the standard alternative for fever and pain.
In children who are old enough to take it, peak blood levels occur about 1 to 1.5 hours after a dose of the liquid or chewable form. The duration of relief is similar to adults: roughly 4 to 6 hours per dose.
Factors That Shorten or Extend the Effect
Several things influence how long a dose of Motrin feels effective for you personally. Body weight plays a role: a 200 mg dose covers less ground in someone who weighs 220 pounds than in someone who weighs 130 pounds. The type of pain matters too. Inflammatory pain, like a swollen joint or a sprain, tends to respond well to ibuprofen because the drug directly blocks the chemicals that drive inflammation. Non-inflammatory pain, like nerve pain, often responds less completely.
Kidney and liver function affect how quickly your body clears the drug. Older adults and people with reduced kidney function may process ibuprofen more slowly, which can extend both its effects and its presence in the body. Dehydration has a similar slowing effect, since the kidneys handle most of the elimination work.
If you find that Motrin consistently wears off well before the 6-hour mark, it may be worth trying the higher end of the OTC dose range (400 mg instead of 200 mg) rather than taking doses more frequently. Keeping at least 6 hours between doses protects your stomach lining and reduces the cumulative load on your kidneys.