AKA:Leucine, Isoleucine, Valine
The Mythology: Delays the onset of fatigue, allowing you to train harder. Like an amino acid version of Creatine. Muscles soak it up and grow huge when you take them post workout.
The Truth: Evidence for Fatigue improvement 50:50. No advantages over a pre or post workout protein shake.
Research: Amino acids are theorised to enhance performance in a variety of ways, such as increasing the secretion of anabolic hormones, modifying fuel use during exercise, preventing adverse effects of overtraining, and preventing mental fatigue.
Basically branch chain amino acids (BCAA’s) are a kind of essential amino acid with a cluster of carbon molecules attached to them. The ones important from a muscle building standpoint are only 3 – Valine, Leucine and Isoleucine. Of these Leucine appears to be the most important. The BCAAs are among the nine essential amino acids for humans, accounting for 35% of the essential amino acids in muscle proteins and 40% of the preformed amino acids required by mammals.
Branched-chain amino acids are often touted as the most anabolic amino acids and many supplements are sold and consumed.
That amino acids, particularly essential amino acids and BCAA’s do cause increased protein synthesis in muscle cells – is not in doubt. Studies show clear evidence that this does occur.1 However this anabolism can be stimulated by a very small quantity of essential amino acid, say a few grams (including those found in a protein meal/drink). Where the big goose-egg appears is in head to head studies between amino acid drinks and protein shakes. Amino acid drinks don’t appear to confer any advantages over pre or post workout protein in terms of boosting protein synthesis in muscles post workout. 2 If you are going to disregard this advice and don’t plan on having any immediate pre or post workout protein – make sure you have your BCAA shake just before working out rather than after. For some weird reason amino acids are more effective when taken before a workout, whereas timing with protein does not appear to make a difference. Also make sure you are having your BCAA’s with carbohydrates for best results.
Remember you don’t really have to have a whey protein shake either, you could just have a protein rich meal just before or after your workout. I have a protein shake because that’s what I find convenient.
1) Am J Physiol Endocrinol Metab. 2001 Aug;281(2):E197-206. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise. Tipton KD, Rasmussen BB, Miller SL, Wolf SE, Owens-Stovall SK, Petrini BE, Wolfe RR.
2)Appl Physiol Nutr Metab. 2009 Apr;34(2):151-61. Stimulation of muscle anabolism by resistance exercise and ingestion of leucine plus protein. Tipton KD, Elliott TA, Ferrando AA, Aarsland AA, Wolfe RR.
How it works: Some investigators believe that increased levels of serotonin may cause fatigue. Hypothetically, BCAA supplementation may delay central nervous system fatigue and enhance performance in prolonged aerobic endurance events by increasing the BCAA:fTRYP ratio and reducing the formation of serotonin. Protein synthesis results not only from provision of substrate for synthetic processes, but also from stimulation of signaling pathways in muscle cells.
Adverse effects: Negligible when consumed in recommended doses.