BCAA (branched-chain amino acids) B
A weak effect: a complete protein does the same better and cheaper
Citable fact
«BCAA (branched-chain amino acids)» — evidence level B. Dosage: 5–10 g with a leucine:isoleucine:valine ratio of about 2:1:1. If complete protein is available in the required amount, a separate benefit has not been shown. Source: PMID 33741748, permanent link to the source in the list below.
How it works
Leucine activates mTORC1, but without the other essential amino acids there is not enough building material for new protein, so synthesis quickly hits a substrate shortage.
Dosage and intake
5–10 g with a leucine:isoleucine:valine ratio of about 2:1:1. If complete protein is available in the required amount, a separate benefit has not been shown.
More often before or during training; the rationale is weak, since the anabolic response to BCAA itself is small.
Forms
Free amino acids and their 2:1:1 and 4:1:1 ratios have been studied. No difference between the ratios in final outcomes has been shown.
What is confirmed
- Practically give no additional gains in strength and mass beyond ordinary protein
- May slightly reduce the perception of effort and muscle soreness
- Can support protein synthesis only when protein in the diet is insufficient
Adverse effects and limitations
- High doses of leucine without other amino acids cause nausea and headache
- Do not cover the protein requirement and may displace it from the diet
- Long-term intake in isolation from complete protein theoretically leads to an amino acid imbalance
Interactions
- BCAA compete with other amino acids for the same transporters
- In renal failure — only as prescribed by a doctor
Who must not use it
- Under 18 years: Not recommended: there are no data, and with normal nutrition there is no benefit.
- Pregnancy and lactation: Not recommended without medical indications.
- kidney failure
- maple syrup urine disease and other amino acid metabolism disorders
Sources
- Isolated Leucine and Branched-Chain Amino Acid Supplementation for Enhancing Muscular Strength and Hypertrophy: A Narrative Review · Plotkin DL, Delcastillo K, Van Every DW · International journal of sport nutrition and exercise metabolism, 2021 · PMID 33741748
- International Society of Sports Nutrition Position Stand: protein and exercise · Jäger R, Kerksick CM, Campbell BI · Journal of the International Society of Sports Nutrition, 2017 · PMID 28642676
See also
Comparisons
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