This is a question we get asked a lot, so I thought I’d take the chance to go into more detail than 140 characters in reply to ‘What are BCAAs?’

So what are BCAAs?

BCAAs are Branched Chain Amino Acids, 3 specific amino acids – Leucine, Iso-Leucine and Valine.

And what are amino acids?

Amino acids are the building blocks of proteins. Proteins are often huge structures that are made of hundreds of amino acids in different orders. There are 22 (20 used in humans) different amino acids and they link together in a long chain/line – the different chemical properties (side groups) of each amino acid interact with one another and cause the protein to fold and change shape, giving it a 3D structure and properties.  Blood cells, muscle tissue and some hormones are a few examples of proteins.

So why are BCAAs special?

The body can produce (synthesize) 11 of the 20 amino acids without digesting any protein (known as non/conditionally essential), the other 9 must be derived from protein sources (essential amino acids). Of these 9 essential amino acids, the 3 BCAAs have been strongly linked with increasing protein synthesis when present in the blood.

So BCAAs build muscle?!

Research by various high profile names in body building shows that BCAAs – predominantly Leucine – stimulate protein synthesis. Although that does not mean they build muscle by themselves – there are other factors involved in this – it does mean they have muscle sparing properties as they stop muscle catabolism (breakdown).

So I should just take BCAA supplements all the time right?

BCAAs are found in your food and protein powder – you digest the protein you eat and the amino acids (including BCAAs) are transported to your blood which promote protein synthesis – so don’t be fooled by products telling you to take them 3-4 times a day. It’s not necessary. Other factors – such as the refractory period (time it takes for your body to be sensitive to stimulation) of your body to perform maximum protein synthesis

When is the right time to take BCAAs?

Personally, I like to take them within the first half of my workout to elevate my plasma levels of BCAAs and stimulate protein synthesis. Working out is actually catabolic, meaning it breaks down muscle! As you are damaging the muscle (by lifting weights or by other method) and the body will burn the amino acids from the damaged muscle as an energy source. As BCAAs enter the blood stream very quickly, they reduce the potential for muscle catabolism (by promoting protein synthesis) and give the body an alternative energy source of amino acids.

I don’t supplement with BCAA pre and post workout as I prefer to get these from animal protein or whey.

How much should I take?

Research suggests as little as 2.5g of Leucine will promote maximum protein synthesis, while other say up to 3.5g is needed to be sure of the same effect. But generally a smaller person with less muscle mass will need a lower dose of BCAAs for the same effect.

BCAAs generally come as a 2:1:1 ratio of Leucine:Isoleucine:Valine – so for a small person, you should take a 5g dose of BCAAs (this gives 2.5g of Leucine) should be sufficient for the maximum effect. A larger, more muscular person should look to be taking a dose of 6-7g of BCAAs to be sure of the same effect.


Should I take BCAAs before cardio?

This is a bit of a ‘catch 22’ with taking BCAAs before fasted LISS. Although BCAAs will have a muscle sparing effect, they will also cause a small spike in insulin (the body will convert some of these amino acids to glucose in the absence of carbohydrates) which will slightly inhibit fat burning. So you have to decide which of those factors is more important to you.

On the other hand, BCAAs before HIIT is something I am not entirely sure of due to the preference it causes in fat oxidation and the increase in mitochondrial biogenesis (and other factors). I will update this article when I know for certain – although right now I cannot see why supplementing with BCAAs before will inhibit fat burning.