Does Ginseng Make You Smarter? What the Research Shows

Ginseng has not been shown to make anyone smarter: no study has measured its effect on IQ, and a Cochrane review concluded that there is "a lack of convincing evidence" that it enhances thinking in healthy people. A 2024 meta-analysis of 15 randomized trials found a small benefit on memory tests (0.19 standard deviations) and no effect on overall cognition, attention or executive function.

This page covers why ginseng has a reputation as a brain tonic, what the single-dose and longer trials found, how the main types of ginseng differ, and what is known about safety and drug interactions. It describes research and is not medical advice.

Ginseng is the root of plants in the genus Panax, and it has been used for centuries in Chinese and Korean traditional medicine. Asian ginseng (Panax ginseng), also sold as Korean or Chinese ginseng, is the most studied. "Red" and "white" ginseng are the same species prepared in two different ways. American ginseng (Panax quinquefolius) is a related species with a different profile of active compounds. Those compounds are called "ginsenosides", and laboratory studies of them are the main reason ginseng is promoted for memory, alongside stress, fatigue and many other uses.

Because ginseng is marketed as a general tonic, the claim that it sharpens the mind rests on a mix of tradition and animal research. The human evidence is much thinner. The National Center for Complementary and Integrative Health summarizes it as "a small amount of research" suggesting some benefit in middle-aged adults but not in young adults. Our page on nootropics and IQ covers the wider market for brain supplements.

Most of the careful trials in healthy people come from a research group at Northumbria University in Newcastle, England, which tested single doses of a standardized Asian ginseng extract called G115 in small crossover designs, where each volunteer takes every dose and a placebo on different days.

• Twenty young adults (Kennedy et al., 2001): A 400 mg dose improved a "quality of memory" score for six hours. The 200 mg and 600 mg doses made a "speed of attention" score worse at later test times, and the two lower doses left people feeling less alert after six hours.

• Thirty young adults during demanding tasks (Reay et al., 2005): A 200 mg dose improved performance on a mental subtraction task and reduced self-rated mental fatigue. Both doses lowered blood glucose, which the authors suggested might explain the effect.

• Thirty young adults over eight days (Reay et al., 2010): The 400 mg dose improved mental arithmetic and calmness. The 200 mg dose slowed responses on the same arithmetic task. Taking ginseng for a week added nothing beyond the single-dose effects.

• American ginseng (Scholey et al., 2010): In 32 young adults, all three doses of a branded American ginseng extract improved a visual working memory task. The study was funded by Naturex, which made the extract, and two of the eight authors worked for the company.

The pattern across these studies is a few improvements, a few impairments, and effects that change with dose in no consistent direction. With small samples and dozens of outcomes per study, some significant results in each direction are expected by chance. When the 2010 Cochrane review looked at nine trials, mostly in healthy volunteers, it could not pool them at all because they used different doses, durations and outcomes.

The most positive results come from small Korean studies of people with Alzheimer's disease. In a 2008 open-label study, 58 patients took 4.5 grams of Asian ginseng powder a day for 12 weeks and 39 served as controls. Scores on the Mini-Mental State Examination (MMSE), a 30-point dementia screen, and on the Alzheimer's Disease Assessment Scale improved in the ginseng group, then fell back to the level of the control group within 12 weeks of stopping. "Open-label" means patients and staff knew who was taking ginseng, which leaves room for expectation effects. A 2012 trial of heat-processed ginseng in 40 patients with moderately severe Alzheimer's disease, split into four groups of 10, also reported improvements.

A 2025 meta-analysis of eight trials in people with memory complaints, mild cognitive impairment or Alzheimer's disease found that ginseng raised MMSE scores by 0.68 points on average, with a confidence interval running from 0.03 to 1.32. That is less than one point on a 30-point scale, and the lower end of the interval is almost zero. The Cochrane reviewers judged that there was "no high quality evidence" about ginseng's efficacy in dementia.

None of these studies used an IQ test. The Newcastle trials used short computerized tasks, and the dementia studies used screening scales on which healthy adults score near the maximum.

If the 2024 meta-analysis's memory effect of 0.19 standard deviations applied to IQ, it would be worth about 3 points (0.19 multiplied by 15, the IQ standard deviation). It does not apply. The pooled studies mixed healthy volunteers with patients who had cognitive impairment, schizophrenia or Alzheimer's disease, the outcomes were memory tasks, and the same analysis found essentially zero effect on overall cognition (0.06 standard deviations, with a confidence interval from -0.64 to 0.77). A small, uncertain memory effect in a mixed group of patients is a long way from a change in general intelligence.

Population studies add a selection problem. A Korean study of 6,422 older adults found that people who had taken ginseng for five years or more scored higher on a neuropsychological battery than non-users. Long-term users also had more education on average (11.9 years against 7.7) and were more likely to be in a higher socioeconomic group. After the researchers adjusted for these and other factors, the gap on the MMSE disappeared, a smaller gap remained on the broader battery, and ginseng use made no difference to how fast scores changed over four years. People who can afford a lifetime of ginseng differ from those who cannot in ways that matter for test scores.

Short-term use of Asian ginseng by mouth, up to six months, appears to be safe for most people, according to the National Center for Complementary and Integrative Health. Trouble sleeping is the most common side effect, and the herb may lower blood sugar and interfere with blood clotting.

The clotting point has been tested directly. In a randomized trial of 20 healthy volunteers, two weeks of American ginseng reduced the effect of warfarin, a blood thinner, compared with placebo, with lower peak blood levels of the drug. Anyone taking warfarin, diabetes medicines or other prescriptions should speak with a doctor or pharmacist before using ginseng. The pattern of strong traditional claims and weak modern trials is similar to the one our page on ashwagandha and IQ describes.

No trial has shown that it does. Some small studies find short-lived changes on memory or arithmetic tasks, others find impairments, and none measured IQ.

They are different species with different ginsenosides, and each has a few small positive trials. Those trials used different extracts, doses and tasks, so their results cannot be ranked against each other.

The single-dose trials measured effects one to six hours after a dose. In the Alzheimer's studies, improvements faded after people stopped taking it.

No trial has shown that it does. Population studies linking long-term use with better scores are confounded by education and income, and the Cochrane review found no high-quality evidence in dementia.

Ginseng can interact with some medicines; one trial found American ginseng reduced the effect of warfarin. Ask a doctor or pharmacist before combining it with any prescription drug.

Ginseng has been studied for decades, and the research still does not show that it raises intelligence. The trials in healthy people are small and point in different directions, the dementia studies are small and the best known was unblinded, and the best pooled estimate for memory is about a fifth of a standard deviation on tasks far narrower than an IQ test. If you want an accurate measure of your reasoning ability, take a full-length online IQ test.

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Hero image: Panax ginseng in Kitchen, by Peachyeung316, CC BY-SA 4.0. Via Wikimedia Commons.