A general blanket statement referring to the abilities of the mind to pass tests put on it. Shares components of a lot of other cognitive phenomena, and not to be confused with Memory, Attention, or Anxiety.

This page features 3 unique references to scientific papers.

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The Human Effect Matrix looks at human studies (excluding animal/petri-dish studies) to tell you what supplements affect Cognition
Grade Level of Evidence
A Robust research conducted with repeated double blind clinical trials
B Multiple studies where at least two are double-blind and placebo controlled
C Single double blind study or multiple cohort studies
D Uncontrolled or observational studies only
Level of Evidence
Magnitude of Effect Size
Scientific Consensus Comments
B Rhodiola Rosea
Comparative Health Goals evidence only available to buyers of our Supplement-Goals Reference

All information is still available and viewable on their respective supplement page.
B D-Serine
B Ginkgo biloba
B L-Tyrosine
B Modafinil
B Panax ginseng
B Phosphatidylserine
C Glycine
C Green Tea Catechins
C Kava
C L-Carnitine
C Nicotine
C Nigella sativa
C Phenylpiracetam
C Pycnogenol
C Sceletium tortuosum
C Zinc
C Bacopa monnieri
C Black Cohosh
C Choline
C Cocoa Extract
C Dehydroepiandrosterone
C Marijuana
C Resveratrol
C Sarcosine
D Pramiracetam
D Pueraria lobata
D Piracetam


  1. Chiu S1, et al Proof-of-Concept Randomized Controlled Study of Cognition Effects of the Proprietary Extract Sceletium tortuosum (Zembrin) Targeting Phosphodiesterase-4 in Cognitively Healthy Subjects: Implications for Alzheimer's Dementia . Evid Based Complement Alternat Med. (2014)
  2. Terburg D1, et al Acute effects of Sceletium tortuosum (Zembrin), a dual 5-HT reuptake and PDE4 inhibitor, in the human amygdala and its connection to the hypothalamus . Neuropsychopharmacology. (2013)
  3. Nell H1, et al A randomized, double-blind, parallel-group, placebo-controlled trial of Extract Sceletium tortuosum (Zembrin) in healthy adults . J Altern Complement Med. (2013)

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