You must be joking mate, everything, and I mean EVERYTHING from Levi jeans to Colgate toothpaste can and is forged nowadays, faked by some scrote and sold as the real thing in very authentic looking packages. Even some of the big chains like Boots have been fooled and actually bought fake stuff at times.
The problem is, the fake stuff not only does not work, it may even be lethal, the people who make it don't give a toss if you die in agony after taking it, all they care about is pocketing your money and moving on to the next customer. There could be absolutely anything in it, but at least buying from a pharmacy I know I have a good chance of getting the right stuff!