Effect of Alpinia galanga on Mental Alertness and Sustained Attention With or Without Caffeine: A Randomized Placebo-Controlled Study

J Am Coll Nutr. 2017 Nov-Dec;36(8):631-639. doi: 10.1080/07315724.2017.1342576. Epub 2017 Sep 14.


Objective: Although Alpinia galanga has been reported to improve cognitive performance in animals, it has not been thoroughly studied for its potential psychostimulant effect in humans. A randomized, double-dummy, double-blind, placebo-controlled cross-over study was conducted to determine the effect of A galanga on mental alertness and sustained attention in comparison with caffeine and placebo in participants with a habitual caffeine intake.

Methods: Fifty-nine participants (18-40 years and body mass index of ≥18.5 and <25.00 kg/m2) with moderate caffeine consumption were enrolled. The participants had a Generalized Anxiety Disorder-7 score ≤7, Patient Health Questionnaire-9 score ≤14 and a Jin Fan's Attention Network Test alertness score of 50 ± 20 ms. The interventional product (placebo, A galanga proprietary extract [E-AG-01], caffeine, and a combination of E-AG-01 with caffeine) was administered to the participants, followed by sequential administration of the remaining interventions on the consecutive study visits; the effects on mental alertness, sustained attention, and sleep architecture, along with safety and tolerability, were analyzed by validated methods.

Results: In the E-AG-01 group, the alertness score was increased by 11.65 ± 23.94, 12.50 ± 19.73, and 12.62 ± 0.68 ms from baseline at 1, 3 (p = 0.042), and 5 hours, respectively, indicating its efficacy to enhance mental alertness and the increase in alertness score as compared to placebo. In the composite group (E-AG-01 with caffeine), mean response time was significantly reduced, by 15.55 ms (p = 0.026) at 3 hours.

Conclusions: A galanga (E-AG-01) induces a beneficial effect in mental alertness and the combination of A galanga with caffeine impedes the caffeine crash and improves sustained attention at 3 hours. Thus, these stimulant effects might yield a new usage for A galanga as a key ingredient in energy drinks or similar products.

Keywords: Alertness; Alpinia galanga; attention; caffeine crash; energy drink; response time.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Adult
  • Alpinia / chemistry*
  • Anxiety / drug therapy
  • Attention / drug effects*
  • Body Mass Index
  • Caffeine / administration & dosage*
  • Central Nervous System Stimulants / administration & dosage
  • Cross-Over Studies
  • Double-Blind Method
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Plant Preparations / administration & dosage*
  • Reaction Time
  • Sleep
  • Surveys and Questionnaires
  • Young Adult


  • Central Nervous System Stimulants
  • Plant Preparations
  • Caffeine