If you’ve spent time scanning the shelves at a vitamin and supplement store, you’ve probably seen them – “brain-boosting” supplements claiming to improve memory and other cognitive functions. As fears about Alzheimer’s and other forms of dementia are exploding, willingness to buy the pitch that brain health can come in a pill is rising as well.

But scientists are calling foul, saying pitches claiming supplements can prevent or reverse cognitive decline are fueling a multi-billion dollar industry built on “pseudomedicine.”  In an editorial published in JAMA, a team of neurologists is urging doctors to educate themselves on brain supplements and provide patients with “honest scientific interpretation” of alleged evidence behind the marketing claims.

“Dietary supplements marketed for brain health are a pseudomedicine practice that patients often ask about,” said first author Dr. Joanna Hellmuth, a neurologist at the University of California San Francisco Memory and Aging Center.

“No known dietary supplement prevents cognitive decline or dementia,” Hellmuth’s team writes in the editorial, “yet supplements advertised as such are widely available and appear to gain legitimacy when sold by major US retailers.”

The industry pitching brain-health supplements is big and getting bigger – sitting on nearly $3.2 billion in sales, according to recent estimates, and expected to grow another 8% over the next four years. Those resources support “high-penetration consumer advertising through print media, radio, television, and the internet,” say the neurologists, for products that don’t undergo US FDA testing for “safety and review of efficacy” that drugs must pass before they can be marketed to consumers.

Because supplements aren’t classified as “drugs”—as defined in the Dietary Supplement Health and Education Act (DSHEA) of 1994—they are considered “safe” until proven otherwise. The DSHEA gives the FDA permission to stop a company from making a supplement only when the agency can prove it poses a significant risk to public health. Since these products don’t undergo clinical trials before being sold, they can only be found “unsafe” after causing harm, which, as pointed out by the American Cancer Society, “is the reverse of the way prescription and non-prescription drugs are handled.”

Often the supplements are “promoted with testimony rather than science,” a practice that’s been noted by the Alzheimer’s Association in public outreach attempting to educate consumers. Personal testimonials can sound persuasive (consider the selling power of product reviews on Amazon, for example) but they are anecdotal, not scientific, and don’t constitute scientific evidence no matter how sincere or well stated.

Other forms of “evidence” come packaged as what the physicist Richard Feynman once called “cargo cult science,” a term the neurologists revisited in the editorial to describe the marketing of “…evidence presented in a scientific-appearing format that lacks actual substance and rigor.”  Feynman said that a feature of scientific integrity is “bending over backwards to show how [a study] may be wrong…” In the case of supplement marketing, the neurologists argue this feature “is often lacking when interventions are promoted for financial gain.”

Often this form of “evidence” is drawn from studies published in journals of questionable credibility. When positioned in advertising, these studies often seem valid to the average consumer. But when investigated more deeply, major methodological flaws appear that undermine the results.

“The primary scientific articles superficially appear valid, yet lack essential features, such as sufficient participant characterization, uniform interventions, or treatment randomization with control or placebo groups, and may fail to include sufficient study limitations,” said the neurologists.

Health care professionals “have the responsibility to learn about common pseudomedicine interventions,” and educate their patients, the editorial concludes, and offers several steps to achieve the objective.

“Understand that motivations to pursue such interventions often come from a desire to obtain the best medical care, and convey that understanding to the patients,” is first priority according to the neurologists, underscoring that the concerns about brain health fueling the sale of many supplements are real and should be acknowledged as such.

Other steps offered include, “Provide honest scientific interpretation of any supporting evidence, along with the associated risks and costs” and “Differentiate testimony from data, and assess whether studies display scientific integrity by ‘bending over backward’ to address any limitations.”

“An argument can be made that even though pseudomedicine may be ethically questionable, these interventions are relatively benign and offer hope for patients facing an incurable disease,” added the neurologists. “However, these interventions are not ethically, medically, or financially benign for patients or their families.”