Tylenol After a Marathon- Does it Help or Hurt?

Participants treated with acetaminophen extended release (ER) reported a significantly greater decrease in the primary endpoint of average change from baseline in muscle soreness on the day of the marathon (day 1) than did placebo. In addition, the adjusted mean average interference with sleep was significantly lower for acetaminophen ER than for placebo. -A Randomized, Placebo-controlled Trial of Acetaminophen Extended Release for Treatment of Post-marathon Muscle Soreness.

BUT WAIT! Read this comprehensive review by Jonathan Savage on the NEGATIVE impact of non-steroidal anti-inflammatories on post run recovery and healing.

MY COMMENT: Let nature take it's course after a marathon, have a few beers, and forego the tylenol.

Would Tylenol Help Your Race Time?

Acetaminophen (Tylenol) was found to increase power output and 10 mile time trial time (26:15 vs 26:45 on the placebo ride) among 12 cyclists.  These findings support the notion that exercise is regulated by pain perception, and increased pain tolerance can improve exercise capacity. (J. of Applied Physiolgy)

According to medicinenet.com, acetaminophen is a pain reliever that can potentially harm liver in excessive doses or if you drink alcohol.  The recommmended dose is 325-650 mg every 4-6 hours. 

I wouldn't make it a habit, and I would not use it in a marathon (dehydration may increase concentration of the drug as your liver tries to clear it), however I might consider popping a couple of tylenol an hour before my next hard 5K.