When restrictions on pseudoephedrine were put in place a decade(!) ago and drug companies reformulated using phenylephrine, I noticed a marked decrease in effectiveness. It’s been worth the effort to ask the pharmacist for the real thing, which is still available behind the counter (at least in California), though you have to let the state track how much you’re buying, just in case they think you’re going to cross the Heisenberg threshold.
A new study confirms: phenylephrine just doesn’t work, at least not at the approved dosage.
But hey, at least no one’s making meth anymore, right? Right? 😕