[14]

Tylenol is a pain reliever so may help with pain. Something like ibuprofen may be a better option, speak to your doctor, as it not only helps with pain but acts as an anti-inflammatory. The important thing to note is that it's effects do not happen instantly but something like several days later so if you have a knee issue, taking it regularly as directed by doctor or manufacturers instructions and not just when your knee hurts can really speed up recovery.

As for your question well you basically just have to trust the science. At some point a rat in a lab probably was intentionally injured next to another rat in the same position and one would get the treatment and the other not. They would then see who healed faster. Things like Acetaminophen and Ibuprofen have been around a long time and studied extensively so they have a good understanding of it's efficacy.

Lastly placebo effect seems to be a real effect so if you do something and you think it might help it might help.

[lazide]

Ibuprofen has some well known (and negative) side effects, including ulcers, increased risk of stroke and heart attack, and even significantly increased malformed sperm production [https://www.sciencedirect.com/science/article/abs/pii/S00456...]

Vitamin I is not, well, actually a vitamin.

[literalAardvark]

It also drastically lowers the integrity of rebuilt tendon/ligament, say after a sprain.

Seems all that inflammation might actually be doing something.

[LoganDark]

poor rat :(

[andriesm]

No they're lucky, all the best medical discoveries are for them.