(alashi/Getty Images)

Consumer Reports has no financial relationship with any advertisers on this site.

The signs of memory loss can be bewildering and scary: misplaced keys, a forgotten street name, that task you suddenly can’t remember. It’s no wonder that, according to the Nutrition Business Journal, sales of supplements touted as memory boosters nearly doubled between 2006 and 2015.

But according to a review of studies published in December, there’s virtually no good evidence that such products can prevent or delay memory lapses, mild cognitive impairment or dementia in older adults. In fact, says Pieter Cohen, an associate professor of medicine at Harvard Medical School, some may do more harm than good.

Here’s what the science says about taking supplements for brain health, and what you should do instead.

What the studies reveal

Some of the more popular supplements marketed for memory enhancement are fish oils (omega-3 fatty acids); B vitamins such as folate, B6 and B12; and ginkgo biloba extract, made from the dried leaves of a ginkgo tree. But decades of research have yet to demonstrate their benefits.

One study published in the Lancet Neurology in 2012, for example, found that among 2,854 older adults with memory complaints, those who took ginkgo biloba extract twice a day for five years had no fewer cases of Alz­heimer’s than those who took a placebo.

As for fish oil, some studies have found that people with diets high in omega-3s — which are found in fatty fish such as salmon — may have a lower risk of dementia. But similar benefits are not linked to supplements: A 2012 review of data on thousands of older adults found that those who took omega-3 fatty acid supplements had no fewer dementia diagnoses or better scores on tests of short-term memory than those who took a placebo.

B vitamins have not fared any better. A 2015 review of studies found that supplementation with B6, B12 and/or folic acid failed to slow or reduce the risk of cognitive decline in healthy older adults and did not improve brain function in those with cognitive decline or dementia.

Our experts also recommend avoiding branded “memory boosting” blends.

A lack of regulation

A 2017 Government Accountability Office report analyzed hundreds of ads promoting memory-enhancing supplements online and identified 27 making what seemed to be illegal claims about treating or preventing diseases such as dementia.

But even legal claims that suggest supplements will improve, boost or enhance your memory “don’t have to have any data to justify them,” says Lon Schneider, a professor of psychiatry and the behavioral sciences at the Keck School of Medicine at the University of Southern California. (“Dietary supplements cannot cure, mitigate, treat, or prevent Alzheimer’s, dementia, or any disease,” said a statement from the Council on Responsible Nutrition, an industry group, responding to the GAO report.)

Supplements are also loosely regulated, and some may even contain undisclosed ingredients or prescription drugs. Many interact (sometimes dangerously) with medications: Ginkgo biloba, for example, should never be paired with blood thinners, blood pressure meds or SSRI anti­depressants. “Don’t be misled by hype,” says Marvin M. Lipman, Consumer Reports’ chief medical adviser. “They are not only a waste of money, but some can also be harmful.”

Three strategies to try instead

Do a brain workout. Enhancing reasoning and memory abilities — learning a new language, for instance — might help delay or slow decline. A 10-year trial found that such training (though not computerized “brain games”) can help increase cognitive processing speed and sharpen reasoning skills.

Exercise your body. In 2011, one study estimated that a million cases of Alzheimer’s disease in the United States were caused by sedentary lifestyle. Several studies have found that physical activity — walking, weightlifting, yoga or tai chi, for example — may delay or slow cognitive decline but not prevent it.

Manage blood pressure. Lowering blood pressure dramatically reduces the risk of heart disease and stroke, which are risk factors for memory loss.

 Copyright 2018, Consumer Reports Inc.

Consumer Reports is an independent, nonprofit organization that works side by side with consumers to create a fairer, safer, and healthier world. CR does not endorse products or services, and does not accept advertising. Read more at ConsumerReports.org.