As frustrating as colds and allergies may be to those who suffer from them, even more sobering is the notion that popular remedies we think are treating them may be ineffective at relieving our stuffy noses.

The U.S. Food and Drug Administration (FDA) is deliberating about removing the designation "generally recognized as safe and effective," or "GRASE," for the common ingredient known as phenylephrine in popular nasal decongestants after an advisory panel to the agency found on Tuesday the drug is ineffective when taken orally. 

The GRASE designation allows manufacturers to market phenylephrine without filing an FDA application.

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Their impending decision could upend the market for the cold and allergy industry, which generated almost $1.8 billion in sales last year, according to data presented by FDA officials.

Companies may be required to remove oral decongestants containing phenylephrine from shelves or reformulate them without the ingredient. 

"The FDA held this advisory committee meeting to seek input from the advisory committee on new data on the effectiveness of oral phenylephrine as a nasal decongestant that have become available since the agency last examined the issue," an FDA spokesperson told Fox News Digital.

Phenylephrine is an ingredient in common over-the-counter (OTC) cold and allergy medications, such as Dayquil, Mucinex, Benadryl Allergy Plus Congestion and Sudafed PE.

The 16-member committee unanimously voted "no" to the following question: "Do the current scientific data that were presented support that the monograph dosage of orally administered phenylephrine is effective as a nasal decongestant?"

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The FDA previously reviewed the topic in 2007, ultimately deciding to keep the drug on the market at the time — despite a systemic review that year finding "insufficient evidence that oral phenylephrine is effective for nonprescription use as a decongestant."

Since 2007, several large placebo-controlled trials provide more definitive research that there is no evidence that standard and higher doses of oral phenylephrine relieves nasal decongestion. 

The nose is often the first line of defense when the body is trying to beat a respiratory virus. 

When we have a cold, the immune system sends white blood cells to fight the infection in our nasal passages. This can lead to a stuffy nose and mucus production. 

Phenylephrine works to decrease the congestion by constricting the blood vessels in our nose and sinuses to reduce swelling. 

One adverse side effect is an increase in blood pressure at higher doses.

"It just isn’t effective when swallowed since more than 99% of the dose is inactivated and doesn’t get into the bloodstream," Leslie Hendeles, Pharm.D., professor emeritus in the College of Pharmacy at University of Florida, based in Gainesville, told Fox News Digital. 

Once we ingest phenylephrine, it gets inactivated after it passes through the liver and by gut enzymes, so there is not enough drug left by the time it reaches our nose. 

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Although phenylephrine is not effective orally — it is effective when administrated in alternative ways, the pharmacist explained.

These include topically as a nasal spray, as eye drops to dilate pupils, and intravenously into the bloodstream to reverse low blood pressure during surgery.

"Spraying phenylephrine, or the longer acting oxymetazoline, directly into the nose produces about 1 million times more drug in the nasal mucosa than swallowing it," he added.

In 2015, Hendeles, together with another one of his colleagues, petitioned the FDA to reevaluate the decision on allowing oral phenylephrine in nasal decongestants.

This prompted the FDA’s current advisory meeting.

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"The FDA Review Team has concluded that oral phenylephrine is not effective at relieving a stuffy nose from either a cold or allergy and the Nonprescription Drugs Advisory Committee has just voted unanimously in agreement with the FDA," Hendeles told Fox News Digital.

"There should be no concern on the part of patients since there are many effective alternatives, including a topical nasal spray containing phenylephrine."

Now that the advisory committee has made its recommendation, the FDA will be reviewing cold, cough, allergy, bronchodilator and antiasthmatic drug products for OTC human use (OTC Monograph M012).

An OTC Monograph establishes the active ingredients under certain categories that an OTC drug is GRASE for its intended use, according to the FDA website. 

"If the FDA determines that oral phenylephrine is no longer considered [GRASE] under the conditions of use in [OTC Monograph M012], the FDA would issue a proposed order to amend OTC Monograph M012 by removing oral phenylephrine as a GRASE active ingredient from that monograph," a FDA spokesperson told Fox New Digital. 

People will have the opportunity to comment on the proposed order.

"During this time period, the marketing status of oral phenylephrine would not change," the FDA spokesperson clarified.

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The Consumer Healthcare Products Association (CHPA), which represents leading manufacturers and marketers of OTC drugs, expressed caution before the FDA makes a final decision. 

"We are disappointed by the outcome of today’s FDA Advisory Committee meeting because its non-binding recommendation is at odds with the numerous clinical trials and previous regulatory determinations affirming oral phenylephrine (PE) as a safe and effective decongestant at its labeled dose," said Scott Melville, CHPA president and CEO, on Tuesday in a September 12 statement shared with Fox News Digital. 

He warned about "significantly negative unintended consequences associated with any potential change in oral PE’s regulatory status."

"The FDA has no further information to provide at this time regarding the timing of any decision the agency may make following the advisory committee meeting," an FDA spokesperson told Fox News Digital.