Effects of dietary sports supplements on metabolite accumulation, vasodilation and cellular swelling in relation to muscle hypertrophy: A focus on "secondary" physiological determinants.
Level 5 - mechanism / opinion, no new human data
Narrative mechanistic review without systematic search or original data
PubMed 30682546 · doi:10.1016/j.nut.2018.10.011
What was done
This narrative review examined the literature on three classes of dietary sports supplements—nitric oxide precursors/vasodilators, anaerobic energy aids (beta-alanine, creatine), and organic osmolytes (creatine, betaine)—and evaluated their proposed roles in secondary physiological determinants of muscle hypertrophy (vasodilation, metabolite accumulation, and cellular swelling).
What was found
The abstract reports no quantitative data or specific effect sizes. It notes that while these supplements improve muscle performance, direct evidence demonstrating that they promote muscle mass accretion specifically via secondary pathways like exercise-induced hyperemia and cellular swelling is scarce and requires further research.
Why it matters
It highlights potential vascular, fluid-balance, and metabolic mechanisms through which common sports supplements may contribute to muscle hypertrophy beyond direct improvements in training volume.
Limits
This is a narrative review with no systematic search criteria, meta-analysis, or new human experimental data. The authors acknowledge that literature directly evaluating these proposed secondary mechanisms is scarce.