This seems to be a very scientific discussion, which I appreciate. I know anecdotal reports are problematic, but for whatever its worth, I experienced great athletic benefits from supplementing with amino acids.
I have a history of experience & measurable, lab documented results with excellent nutrition & athletics (though I fall off the wagon at times; hence my interest in DIY Soylent). Although I was supposedly getting an excellent amino acid profile from a healthy balanced diet, when I supplemented extra doses of amino acids, it was a dramatic difference. I’m not sure about cardio impact, but I was never sore and felt always ready to hit the gym.
I did not focus on only essential amino acids nor only the branched chain amino acids (BCAAs) of many bodybuilder protein blends – leucine, isoleucine, valine. Rather, I had researched different amino acids on Pubmed and selected ones of particular interest based on the most intriguing studies (to me).
I gradually added the following, one at a time, spaced about a week apart:
– Carnitine (biosynthesized from amino acids)
Some were for the excellent muscle recovery effects I mentioned. Some were for antioxidant (cardio) or other benefits, that I can’t confirm if they were helpful or not. Some are vasodilators, which btw feels great!
As powdered form in smoothies, they tasted horrible and some made me nauseous since this is not a slow release form. I did much better with slow release capsules.
I’m planning to add tyrosine & phenylalanine for other benefits.