How Two Pharmacists Figured Out That Decongestants Don't Work

There's no good evidence phenylephrine works for clearing up your nasal passages, at least at the doses sold over the counter. Nasal decongestant is what it's labeled to be sold as, you're referring to the same idea just with different words. Study after study has failed to show any difference between phenylephrine and placebo. In most studies both groups report getting somewhat better, there's just no difference to placebo. Suggesting improvements are just due to some combination of time and placebo effect.

https://pubmed.ncbi.nlm.nih.gov/26143019/

That's just one but there's many others.

Pseudophedrine on the other hand has been shown to be superior to placebo many times (again just one source below, but there are others):

https://pubmed.ncbi.nlm.nih.gov/15794071/

That one is still available. It's just kept behind the counter because of concerns it could be used in the manufacture of meth.

The oral absorption of phenylephrine is erratic. Perhaps that is why it was not used as an oral decongestant until it was the only choice. It had long been known that enzymes in the gut lining metabolized oral phenylephrine to inactive metabolites, reducing the amount of the active compound that could enter the bloodstream.

The most cited study found that an oral dose of phenylephrine had an absorption rate of 38 percent of an oral dose of phenylephrine, but this study measured more than just the compound's active form. Later studies with more sensitive tests found that less than 1 percent of oral phenylephrine enters the bloodstream in an active form.

You stand alone against many pharmacist who study the medicine, research scientists who test the medicine, and pharmaceutical labs that make the medicine. The only people who want to continue making phenylephrine are those who make hundreds of millions in the misconception it will help you. That's stealing, even if no one gets hurt.

You are probably very sensitive to phenylephrine so it works with those very small amounts. Everyone else is not you. You are lucky to find a solution on the shelf right now. Overwhelmingly we others cannot. It is this very limited helpfulness that has caused phenylephrine to lose its GRASE status (Generally Recognized as Safe & Effective) since it is safe but not broadly effective.