No, commercial speech in fact, can be limited and regulated and does not enjoy full 1st ammendment protection. Just ask the Marlborough Man.
Well, what you seemed to imply on your earlier post was that newspaper advertising (or commercial speech) does not enjoy First Amendment protections. In fact, it does.
That isn't to say advertising or commercial speech cannot be regulated, just like every other type of speech - including some political speech - is.
And nowadays, most restrictions on tobacco advertising aren't because the Government passed a law or laws but because the tobacco companies agreed to advertising restrictions as part of the settlement(s) in the lawsuit(s) againt them.