Most all BCAA powders are fairly primal-friendly. The worst thing you'll run into is the artificial sweetener that most contain. Although I'm not an advocate for supplementation I do see the advantages of bcaas when training fasted. I've heard good things about Scivation Xtend. It is one of the more expensive bcaa complexes but it contains a higher concentration of amino acids. You'll get more bang for your buck.
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The authority on nutrition for strength and lean mass gains without the use of supplements, meal-timing, or other unnecessary diet methods.