For most adults, the standard single dose of ibuprofen is 200 to 400 mg, taken every four to six hours as needed. The over-the-counter maximum is 1,200 mg per day, while prescription doses for conditions like arthritis can go as high as 3,200 mg per day under medical supervision. The right amount depends on what you’re treating, your age, and your overall health.
Standard Adult Doses
Over-the-counter ibuprofen tablets typically come in 200 mg. For a headache, muscle ache, or mild to moderate pain, the effective dose is 200 to 400 mg every four to six hours. Most people find that 400 mg (two tablets) works well for general pain relief. For menstrual cramps specifically, the recommended dose is 400 mg every four hours as needed, since cramp pain tends to respond best to slightly more frequent dosing.
If you’re buying ibuprofen off the shelf, keep your total at or below 1,200 mg in 24 hours (that’s six 200 mg tablets). Prescription-strength ibuprofen for chronic conditions like osteoarthritis or rheumatoid arthritis ranges from 1,200 to 3,200 mg per day, divided into three or four doses. Those higher amounts require a doctor’s oversight because the risk of side effects climbs with dose and duration.
How Quickly It Works
Ibuprofen starts relieving pain within 30 to 60 minutes of swallowing a dose. Pain relief generally lasts four to six hours, which is why the dosing interval matches that window. If you need faster relief, taking it on an empty stomach speeds up absorption. Despite the common advice to always eat something first, there’s no strong scientific evidence that food actually prevents stomach irritation from ibuprofen. Food slows how quickly the drug gets into your bloodstream without changing how much is ultimately absorbed.
That said, if you already have a sensitive stomach or are taking higher doses for several days, eating beforehand may still feel more comfortable even if the data doesn’t confirm a protective effect.
Dosing for Children
Children’s doses are based on weight, not age. If you know your child’s weight, use that over the age listed on the box. Ibuprofen should not be given to babies under 6 months old, as it hasn’t been shown to be safe in that age group and isn’t FDA-approved for them.
For children 6 months and older, ibuprofen can be given every 6 to 8 hours as needed. The spacing is longer than for adults. Children’s liquid formulations come with a dosing syringe or cup marked by weight, and the adult dose ceiling is 400 mg per dose. If your child is dehydrated from vomiting or diarrhea, hold off on ibuprofen until they’re rehydrated, because dehydration combined with ibuprofen can stress the kidneys.
Who Should Take Less or Avoid It
Not everyone can safely take the standard dose. Several groups need to start lower or skip ibuprofen entirely:
- Adults 75 and older: Older adults face a higher risk of stomach bleeding and kidney problems. Starting at the lowest effective dose, often 200 mg, and using it for the shortest time possible is the safer approach.
- People with kidney disease: Ibuprofen reduces blood flow to the kidneys. If you have impaired kidney function, even standard doses can cause further damage. Severe kidney impairment (filtration rate below 30 mL/min) rules out ibuprofen completely.
- People with heart disease or recent heart attack: Ibuprofen increases the risk of cardiovascular events. If you’ve had a heart attack, stroke, or heart failure, it’s generally not recommended.
- People with a history of stomach ulcers or GI bleeding: Ibuprofen can reopen or worsen ulcers and cause internal bleeding, sometimes without warning symptoms.
- Pregnant women at 20 weeks or later: Ibuprofen can harm the fetus and cause complications during delivery when taken in the second half of pregnancy.
- People with asthma and nasal polyps: This combination raises the chance of a serious allergic-type reaction to ibuprofen.
Medications That Change the Risk
Ibuprofen interacts with several common medications in ways that increase bleeding or reduce how well those drugs work. Blood thinners are the biggest concern, since ibuprofen also has a mild blood-thinning effect and the combination raises bleeding risk significantly. Aspirin (even low-dose daily aspirin for heart protection), other anti-inflammatory painkillers like naproxen, and oral steroids all amplify the same stomach and bleeding risks.
Common antidepressants in the SSRI and SNRI categories (including fluoxetine, sertraline, duloxetine, and venlafaxine) also increase the chance of bleeding when combined with ibuprofen. If you take any of these, your effective safe dose of ibuprofen may be lower than the standard recommendation, or you may need a different pain reliever altogether.
What Happens if You Take Too Much
Occasional accidental overdoses with ibuprofen are relatively forgiving compared to some other painkillers. Doses up to 100 mg per kilogram of body weight generally cause only minor symptoms. For a 70 kg (154 lb) adult, that’s about 7,000 mg, well above any recommended dose but unlikely to be life-threatening.
Serious toxicity begins around 400 mg per kilogram. At that level, seizures, dangerously low blood pressure, slowed breathing, and kidney and liver damage become real risks. The practical takeaway: accidentally doubling up on a dose is unlikely to cause serious harm, but routinely exceeding the daily limit wears down your stomach lining and kidney function over time, even if you never hit an acutely toxic amount.
Getting the Most From the Lowest Dose
The safest strategy with ibuprofen is to take the smallest amount that controls your pain and stop as soon as you can. For a one-off headache, try 200 mg first. If that doesn’t cut it after an hour, 400 mg is appropriate next time. For ongoing pain lasting more than a few days, the lowest effective dose for the shortest duration matters more than maximizing each individual dose. Long-term daily use, even within the recommended range, increases your cumulative risk of stomach, kidney, and cardiovascular problems.