The Effects of Consuming Amino Acids L-Arginine, L-Citrulline (and Their Combination) as a Beverage or Powder, on Athletic and Physical Performance: A Systematic Review

Round 1

Reviewer 1 Report

The work deals with the problem of the consumption of amino acids in the human diet in a very interesting way. The aim of this study was to determine the efficacy of consuming standalone 23 L-Arg, L-Cit, and their combination (in the form of powder or beverage) on blood NO level and 24 physical performance markers. The work is well organized. The purpose of the work was correctly described and achieved. The methods used do not raise any objections. The course of the analysis is presented graphically, which will make it easier to follow the analytical course. The results are presented in the form of tables, they are legible, they reliably present the results. The discussion of the results was well described with the correctly cited literature. However, out of 100 quoted literature items, the latest literature is from 2020. I propose to supplement the literature with the period of the last 2 years. 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Thank you for the opportunity to review “The effects of consuming amino acids L-arginine, L-citrulline (and their combination) as a beverage or powder, on athletic and physical performance: a systematic review”. I found this manuscript to be very well put together and interesting. The review procedures followed were well done and results appeared consistent with the review.

Concern:

Page 2, starting line 84: The paragraph reviews several articles which use L-Arg along with other substances (BCAA, etc.), then makes a statement that “Research suggests that supplementation with L-Arg alone does not improve . . .”. Are there any articles that used solely L-Arg and did not find a response? If not, it might be better to say something like, “Supplementation of L-Arg, along with _________, has been shown to improve . . . however, there are no studies looking solely at L-Arg supplementation alone.”

Abstract, line 27: 0.075g/kg “or” L-Arg; Should be “of”

Author Response

Please see the attachment.

Author Response File: Author Response.docx