Effects of Five Amino Acids (Serine, Alanine, Glutamate, Aspartate, and Tyrosine) on Mental Health in Healthy Office Workers: A Randomized, Double-Blind, Placebo-Controlled Exploratory Trial

Nutrients. 2022 Jun 6;14(11):2357. doi: 10.3390/nu14112357.


Background: The importance of maintaining good mental health with overall well-being has recently drawn attention from various spheres of academics and the working population. Amino acid intake has been reported to reduce depression symptoms and other mental health problems. However, the effectiveness of amino acid intake (i.e., single or combined) remains unknown. In this study, we assessed a combination of five amino acids (serine, alanine, glutamate, aspartate, and tyrosine; SAGAT) reported to regulate mental health.

Methods: A randomized, double-blind, placebo-controlled exploratory trial was conducted. Participants, aged between 20 and 65 years with fatigue sensation, were randomized to receive either SAGAT or the placebo and ingested them for four weeks. A transient mental work was loaded at day 0 and after four weeks of intervention. As the primary outcomes, the fatigue sensation was assessed. The mood status, cognitive function, work efficiency, and blood marker were also measured as secondary outcomes.

Results: The number of participants analyzed for the efficacy evaluation were 20 in SAGAT and 22 in the placebo. There were no significant differences in the primary outcomes. However, as the secondary outcomes, the SAGAT group showed a significant improvement in motivation and cognitive function in the recovery period after mental work loaded in a four-week intervention compared to the placebo.

Conclusion: The current findings suggest that SAGAT contributes to maintaining proper motivation and cognitive function.

Clinical trial registration: University Hospital Medical Information Network Clinical Trial Registry (ID: UMIN 000041221).

Keywords: amino acids; cognitive function; mental health; motivation.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Alanine
  • Amino Acids* / pharmacology
  • Aspartic Acid
  • Double-Blind Method
  • Glutamic Acid
  • Humans
  • Mental Fatigue / prevention & control
  • Mental Health*
  • Middle Aged
  • Occupational Health*
  • Serine / pharmacology
  • Treatment Outcome
  • Tyrosine
  • Young Adult


  • Amino Acids
  • Aspartic Acid
  • Glutamic Acid
  • Tyrosine
  • Serine
  • Alanine

Grant support

This research received no external funding.