Branch chain amino acids (BCAAs) are one of the most commonly marketed and consumed supplements on the market.
They are also one of the most useless, and possibly priciest.
Branch chain amino acids are made up of Leucine, iso-leucine and valine, leucine is an essential amino acid that stimulates muscle protein synthesis (MPS) (via mTOR).
So, if BCAA’s contain Leucine, then they’ve got to be good right? MORE, is always better. However, in isolation BCAA’s actually reduce the response from MPS, and can cause leucine to be oxidised rather than used in muscle growth. For leucine to be effective, the other 6 essential amino acids (on top of BCAA’s), have to be present, it’s like starting a car with no petrol.
It gets worse, without the full essential amino acid profile, you would actually start using the amino acids from the muscle you have broken down previously or that which comes from natural muscle protein breakdown on a daily basis. So, you may cause your quads to grow, but you’d be using the breakdown from your biceps.
So, a brief overview shows that getting BCAA’s from foods such as lean meats or even whey protein, is not only more beneficial to actually stimulate MPS, but it’s actually cheaper. I would argue, if your diet is getting you within 1.2-2g/kg of protein daily, you have no need to even think about BCAA’s let alone buy them, it would just result in expensive urine.
Furthermore, here are some of the claims that brnads selling BCAA’s have been known to suggest:-
- BCAAs are fuels during exercise. Whilst BCAA’s do contain calories and therefore theoretically could add to energy stores. Enzymes involved in oxidation are usually too low to allow any major contribution.
- BCAAs spare glycogen, no, as above if they don’t contribute to energy throughout exercise, they wont spare glycogen, as glycogen use is dictated by pre-ingestion, intensity and duration of exercise.
- BCAA supplementation can increase protein synthesis following exercise, whilst this isn’t strictly false, total amino acids would be the determining factor as to whether protein synthesis would be stimulated
- BCAAs reduce muscle damage and reduce muscle soreness, whilst nothing has been seen to show a reduced muscle damage or altered muscle function, BCAA have consistently shown to reduce soreness