Latency and duration of stimulation of human muscle protein synthesis during continuous infusion of amino acids
If essential amino acids (EAAs) stimulate muscle protein synthesis (MPS), can we just sip on them all day long to keep our EAA levels high and build muscle all day long? No...
In the first study of its kind, researchers in 2001 demonstrated that an "increase in the availability of plasma amino acids took between 30 min and 1 h to have any measurable effect on muscle protein synthesis, whereupon MPS was markedly stimulated by ≈2.8-fold for a period of 1.5 h before falling to a value not significantly different from the basal value for the succeeding 4 h."
Despite circulating EAA levels remaining significantly elevated, after just 1.5 hours MPS fell back down to the levels observed prior to ingesting EAAs and remained at that level for a few hours. These findings suggest that spacing out doses of EAAs (or dietary protein) throughout the day is more efficient for MPS than continuous infusion.
Read the full text here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2278544/
Bohé J, Low JF, Wolfe RR, Rennie MJ. Latency and duration of stimulation of human muscle protein synthesis during continuous infusion of amino acids. J Physiol. 2001;532(Pt 2):575-579. doi:10.1111/j.1469-7793.2001.0575f.x