Advil, Panadol and aspirin all claim to treat minor aches and pains, but they're not interchangeable. Ibuprofen (the ingredient in Advil) works the best in most cases -- but all three are probably less effective (and less safe) than you've been assuming.
Julia Belluz at Vox asked experts about the three drugs, including Oxford pain researcher Andrew Moore:
Like all good evidence-based medicine thinkers, he was able to provide a very practical answer: "If you're talking about aspirin in doses of 500 to 1,000 mg or two tablets, 30 per cent of people get relief from acute pain. For acetaminophen [Tylenol] at doses of 500 to 1,000 mg, about 40 per cent have a success. For ibuprofen, in its normal formulation at something around 400 mg or two tablets, about 50 per cent have success."
That's for acute pain, like you'd get from a specific injury. Ibuprofen also beats paracetamol for chronic pain and for headaches, and another expert offered the opinion that paracetamol "is an old drug, obsolete, and should be avoided altogether." In several studies, it didn't work at all.
There are other differences though: Ibuprofen can cause kidney damage and bleeding in your digestive system (especially if you take high doses for a long time); paracetamol is bad for your liver, especially if you've been drinking; and aspirin can cause stomach irritation and interferes with blood clotting. Paracetamol is probably safest for a baby with a fever, and some people (including pregnant women) should avoid ibuprofen. So check with a doctor to be sure, and in the meantime read up at the link below for more on the differences between these common painkillers.