NSAIDS are problematic, to many endurance athletes especially with increasing duration, use, and dehydration. Some athletes appear to do just fine with NSAIDS, but all athletes are faced with their liver having to metabolize synthetic substrates for systemic application, resulting in some side effects for most. As you know I never recommend doing somethin if it hinders the normal human expression of health...Thus, I tend to descriminate when it comes to using NSAIDS, a medication we should avoid and limit when possible. As for Tissue Rejuvenator, It should be tried at 6-8 hours in the heat of day first to see if it agrees with your individual biochemistry. I am not aware of or if any ultrarunners have tried TR in 24 hour events. At present, I can give you no examples of either success or failure, thus your trial first is mandatory. I will ask a few athletes who may have used it in their 24 hour events; as I said, most of them have wrestled with NSAIDS and the accompanying gastric side effects, dehydration, kidney failure, and a host of other problems NSAIDS prolonged use creates.