Cohen-led team concludes phenibut warnings had no deterrent effect

By Hank Schultz

- Last updated on GMT

©Getty Images - Ildo Frazao
©Getty Images - Ildo Frazao

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A research team led by prominent industry critic Dr Pieter Cohen has found that FDA warning letters sent to companies using phenibut in dietary supplements didn’t prevent other firms from continuing to use the illegal ingredient.

The finding was published as a basic research paper today in the journal Clinical Toxicology.​ The research team included Dr Cohen, of Harvard Medical School, John Travis, PhD, of NSF and several other collaborators.

The researchers tested two samples each of four products that listed phenibut or a synonym on the product label.  Each product was made by a different manufacturer, and none of the companies received one of the warning letters that FDA sent out during the 2019 enforcement action.

Phenibut is also known as aminophenylbutyric acid among many other synonyms.  It was reportedly was first developed in the Soviet Union in the 1960s.

Phenibut has a chemical structure similar to the brain chemical called gamma-aminobutyric acid (GABA).  The ingredient has been used to treat anxiety, insomnia, post traumatic stress disorder, alcoholism and other conditions.  It has reportedly also been used as a recreational drug.  It is openly for sale on Internet sites like Nootropics Depot.

The ingredient has never been approved for use in the United States, either as a drug or a dietary ingredient.  It is still used as a prescribed pharmaceutical in Russia. 

Situation didn’t just continue; it got worse

The research team tested the four products first in 2017 and went back and acquired new bottles of the same products to test in August 2019, after the FDA enforcement action.

They found that not only were the products still openly for sale on the market, but that in three of the four cases the phenibut dosages had actually increased. In once case, a product contained 1,137 mg of phenibut, which is more than four times the typical dosage of the drug in Russia, where it is dispensed in 250 mg tablets.  That product did not declare a dosage on the label, the team noted.

Dr Cohen’s team noted that having phenibut on the market is not a matter of some scofflaws ignoring certain technical aspects of federal regulation.  It is a safety concern, they maintain.

“The risks of phenibut have been well documented. More than 1,300 calls to US poison centers have involved phenibut ingestions with lethargy, agitation, tachycardia and confusion among the most commonly reported reactions with coma and death among the most serious adverse events,”​ they wrote.

The researchers also noted that there is evidence for an abuse potential with phenibut.  Health care practitioners have resorted to phenobarbital and baclofen to help wean patients off of this substance.

The researchers concluded with a warning:

“Clinicians should remain aware that, despite FDA warnings, phenibut remains available in high dosages in over-the-counter dietary supplement in the United States.”

Enforcement failure a familiar tale

Marc Ullman, an attorney of counsel with the firm Rivkin Radler, said the situation with phenibut is an all too familiar tale.

“When reading this research I have to say I’m utterly unsurprised. FDA is a law enforcement agency, but these warning letters have absolutely no deterrent effect.  There are no consequences.  The Agency has all the authority it needs.  It just chooses not to exercise it,” ​he said. 

Steve Mister, president and CEO of the Council for Responsible Nutrition, said the industry as a whole should be concerned about the continued presence of this ingredient.

 “CRN is concerned that products containing phenibut are still available online and urges consumers to avoid them. Phenibut is not a legitimate dietary ingredient. Despite all of FDA's blustering two years ago, it's concerning that the agency does not appear to have seriously followed through with aggressive enforcement of products containing phenibut. We urge FDA to follow through with its public statements and pursue consequential enforcement activity beyond warning letters for products marketed as dietary supplements that contain phenibut,” ​he said.

FDA: Committed to advancing strategic priorities

The Food and Drug Administration issued this statement in response to the research:

“The FDA is dedicated to advancing our strategic priorities for dietary supplements: safety, product integrity, and informed decision-making. We appreciate stakeholder interaction that raises awareness and brings needed attention to these matters. We look forward to collaborating with our stakeholders to help ensure that products marketed as dietary supplements are safe, well-manufactured, and accurately labeled, while preserving the original commitment to consumer access the Dietary Supplement Health and Education Act (DSHEA) provided.”

Source: Clinical Toxicology
Quantity of phenibut in dietary supplements before and after FDA warnings 

Authors: Cohen PA, Ellison RR, Travis JC, Gaufberg SV, Gerona R

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