The study involved 12 weeks of resistance training in 36 adults who were in their 60s. Subjects were randomly assigned to take acetaminophen, ibuprofen, or placebo for the duration of the study. The acetaminophen dose (e.g., Tylenol) was 4000 mg/day and the ibuprofen dose (e.g., Advil) was 1200 mg/day. The total daily amount was divided into three doses.
Compared to placebo, the drug-takers saw a 25-50% increase in muscle mass and strength. The authors attribute the benefit to inhibition of cyclooxygenase (COX).
In case you’re tempted to try this hack on yourself, you might want to run it by your doctor first. For instance, I wouldn’t take the acetaminophen if I had chronic liver disease. I’d eschew the ibuprofen if I had kidney impairment, were prone to bleeding, had stomach ulcers or gastritis, or were taking a strong blood thinner.
Update December 20, 2014: Ibuprofen seems to increase lifespan in several species. Humans, too?
h/t P.D. Mangan