Brain Health,
Smart Drugs,

#133: Ginseng with Dr. Andrew Scholey

June 17, 2016

Modern science is proving many traditional herbal medicines to be effective.  In Episode 133, Dr. Andrew Scholey of the Swinburne Centre for Human Psychopharmacology is back to talk about the benefits of Ginseng (see our episode on Bacopa for another example of a traditional herb backed by science).

Mood, Memory, and Mental Fatigue

Numerous studies have confirmed that Ginseng has cognition-enhancing properties, particularly when it comes to memory, mood, and mental fatigue.

A dose of 400mg of Ginseng results in significant improvement in memory throughout the day.  In one study, Dr. Scholey asked participants to learn unique lists of words throughout the day.  The memory-boosting effects of taking Ginseng in the morning lasted well into the afternoon.  Interestingly, the most effective dose was 400mg, not a higher dose of 600mg.

Ginseng also helps you perform better under mental fatigue.  Supplementing with Ginseng protects against low mood and improves cognitive function despite mental fatigue.

And Ginseng has benefits comparable to pharmaceutical heavy-hitters like Modafinil.  In a study comparing the effects of Ginseng and Modafinil, the largest effect size (a measure of how much of an effect a compound has) for Modafinil was 0.77, while the largest for Ginseng was 0.86, meaning that Ginseng had more noticeable effects on certain measures of cognition than Modafinil.  In the case of mental fatigue, Ginseng had double the effect of Modafinil!

Ginseng and Glucose

Everyone knows the brain is an energy hog and takes up about 20-30% of the body’s glucose and oxygen consumption.  You may not know that blood glucose levels are closely linked to cognitive performance.

Ginseng helps to regulate blood glucose levels.  Ginseng seems to help cells involved in cognition take up more glucose and use it more efficiently.  (Ginseng is made up of multiple compounds, so, as you can imagine, there are multiple mechanisms of action.)

American vs. Asian

There are two main types of Ginseng:  American (Panax quinquefolius) and Asian (Panax ginseng).  Asian Ginseng has been studied much more thoroughly and is what is used in traditional Chinese medicine.  The difference between the two types comes down to the levels of different ginsenosides (the active compounds in Ginseng).

American Ginseng has higher levels of Rb1 ginsenosides, while Asian Ginseng has higher levels of Rb2 and RBC ginsenosides.  What does this mean in terms of actual benefits?  American Ginseng boosts working memory (short-term memory), while Asian Ginseng generally improves memory processes — both short-term and long-term memory.  It also improves mood and cognitive performance despite mental fatigue.

Taking Ginseng

It’s important that you find a high-quality extract, since some of the supplements on the market may contain low levels of Ginseng (or even no Ginseng at all!) or contaminated extracts.  A dose of 400mg confers the biggest cognitive benefit.

Dr. Scholey recommends two brands that he’s used in his research:

With these brands, not only are you assured that you’re getting a high-quality extract, but you’re also supporting the companies that actually sponsor research.

There doesn’t appear to be any risk of developing a tolerance to Ginseng, since benefits have only been found after taking acute doses, e.g. immediately after taking Ginseng.  Likewise, there’s no loading period.  You take a pill, get the benefits, and then they wear off.

In terms of timing, there haven’t been any studies on the best time to take it, but for research purposes Dr. Scholey has always administered it in the morning.  Due to the fairly long half of Ginseng (6 hours), taking it too late in the day might disrupt your sleep.

Ginseng is pretty safe, although people with diabetes should discuss with their doctors before starting supplementation.  There have been a few reported cases of Ginseng toxicity, but this is very rare, and seems confined to cases where people took doses tens or hundreds of times the normal amount.

PS:  Ginseng may boost your mood, but so does our weekly newsletter.  Have you joined yet?

Read Full Transcript


  1. Reinis says:

    HI! Can i just eat / make tea from actual Ginseng root to get enough of it?

  2. Jonathan Roseland says:

    He was asked about Ginseng “wash out periods”… A handful of human studies have shown that Ginseng usage improved subjective well being, mood and even social functioning after 4 weeks. Yet around the 8 week marker, the mental health scores were tantamount to that of the placebo, suggesting a tolerance curve. To quote the abstract of a University of Connecticut study: “[Panax Ginseng] improves aspects of mental health and social functioning after 4 weeks of therapy, although these differences attenuate with continued use.” Maybe a good reason to cycle your usage of Ginseng in 4 week increments if your primary objective is to optimize mood.

    1. Jesse Lawler says:

      Good info here Jonathan, thanks. Do you have the URL for that study-abstract you quote? I’d love to update your original comment with that link. 🙂

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