In the quest for more muscle and greater strength, it’s all down to hard work in the gym and clever work in the kitchen. In this article we tell you all about the best amino acids for muscle growth… and if there are any supplements that actually help.
You can train like a demon possessed in the gym and not make much progress. While strength and cardio training is the stimulus for enhanced performance and muscle growth, the adaptation comes from rest, recovery and proper nutrition.
Amino acids have become a popular supplement in the world of athletes and bodybuilders.
But do you even need to supplement these building blocks of protein to build muscle?
Or can you get what you need from nutrition alone?
We take a look…
- What are amino acids?
- Amino acids for performance and muscle growth
- Are BCAA supplements worth the money?
What Are Amino Acids?
If you take some protein and look at it under a microscope you’ll see that it’s made up of strings of molecules. These strings are called peptides… and the individual molecules that make them up are called amino acids.
Imagine a bead necklace as being a protein molecule. The beads are amino acids and the string that goes through them to make the necklace is a peptide helping to join them together.
Essential and non-essential amino acids
Although there are hundreds of different amino acids, only 20 (some scientists suggest 21) are proteinogenic ones – aminos that exists in your body’s protein structures.
The word proteinogenic just means ‘protein creating’.
Of those 20…
- 9 amino acids are classed as ‘essential’
- the remaining 11 are ‘non-essential’
Essential amino acids have to be obtained through diet. If you don’t eat foods containing them you’ll quickly become deficient. These include aminos such as:
The remaining aminos are classed as non-essential as your body can make them itself if you don’t obtain them through a healthy diet. This isn’t a perfect scenario by any stretch, as your body has to use energy to do this. But if it has to it will.
What are BCAAs and why are they important?
The branched chain amino acids – leucine, isoleucine and valine – are classed as essential aminos.
They are called ‘BCAAs’ because of their specific chemical arrangement (they have an aliphatic side-chain with a central carbon that looks like a branch).
Branched chain amino acids are heavily involved in cellular signaling pathways. Their most well-known benefit is their ability to influence protein levels in the body, and as such are an important part of muscle building.
Key Point: Amino acids are the building blocks of protein. They are responsible for maintaining lean muscle mass.
The Muscle Growth and Amino Acid Relationship
Protein is essential for muscle growth. In fact, your muscle is made up of protein (and as such, peptides and amino acids).
Although there are different recommendations on exactly how much protein you should eat per day to maximize the muscle growth response, current guidelines from the Journal of Sport Science suggest 1.3-1.8 grams per kilogram of body weight .
Protein in the diet – muscle cell turnover
Protein intake is important for numerous health and performance reasons.
Not only does this amino-acid-rich nutrient help produce a bunch of enzymes, hormones and antibodies, they’re also important for repair and maintenance of lean tissue.
Each day your body fights a battle called ‘muscle protein turnover’. This refers to the net balance between:
Protein synthesis – the production of new protein cells
Protein degradation – the breakdown of protein cells
Imagine your body’s protein reservoir as a seesaw. On one end you’ve got the potential to build new muscle cells, and on the other is the systems your body has to eat away at existing muscle cells.
If synthesis outweighs degradation you build muscle… but if degradation gets the upper hand, you lose muscle tissue.
So how do you ensure protein synthesis is maximized?
In order to ramp up muscle protein synthesis (MPS) and boost muscle growth you have to cover two main bases:
- Lift weights
- Eat a diet rich in essential amino acids
It’s pretty common sense to think that strength training and regularly lifting weights is the key to triggering muscle growth. In fact, hitting the weights area is the actual stimulus for growth, damaging muscle tissue on a cellular level and forcing it to grow back bigger and stronger.
But that repair, muscle growth and adaptation process can’t be optimized without the proper diet… and that’s where amino acids come in.
Key Point: Optimal protein intake is important to maximize protein synthesis and blunt degradation.
Are There Really Best Amino Acids for Muscle Growth?
It’s worth pointing out from the very start that all proteinogenic amino acids are important for muscle growth.
You need all of the essential aminos (as well as the non-essential) to form peptide bonds and protein cells that will make up lean tissue.
No matter how much you focus on an individual amino acid, if you skip others you won’t build muscle.
The importance of leucine for muscle growth
Before we talk about the importance of the BCAA leucine for muscle growth, let’s be clear – we’re not necessarily talking about supplements. We’re talking about the amino acids obtained from any source, food or otherwise.
Leucine, one of the three BCAAs, has been referred to as the ‘anabolic trigger’  of muscle growth because of its ability to speed up protein synthesis.
If anything, this is one of the best amino acids for muscle growth.
In various studies, leucine has been shown to slow down muscle loss in inactive adults, as well as boost muscle growth in those taking part in regular strength training.
Many of these studies used participants that purposely ate a lower protein diet.
In those that already reach their protein needs for the day, leucine has been shown to offer no additional benefit for muscle growth .
You can get plenty of leucine from a protein-rich diet and only need around 17 mg per kilogram of body weight to optimize the muscle growth response.
Foods that are high in this BCAA include (per 100 g):
- Meat – 3165 mg (beef), 2650 mg (chicken)
- Cheese – 3450 mg
- Seafood – 2293 mg (tuna)
- Soy – 3223 mg
Key Point: Leucine could be thought of as one of the best amino acids for muscle growth as it acts as an ‘anabolic trigger’. However, you can get plenty from a normal diet and don’t need to supplement it.
Dietary Amino Acid Proteins vs Supplementation
Maximizing muscle growth isn’t about eating as much protein as you can. It’s about optimizing protein (and therefore amino acid) ingestion based on your body weight.
As we’ve mentioned, 1.3-1.8 grams per kilogram is as much as you need – lower if you aren’t a top-level athlete who lifts weights 4 or more times each week.
It’s actually quite easy to get your daily protein needs from food. You don’t need an amino acid supplement. And for many people, the ‘best’ amino acids for muscle growth are a waste of time…. particularly BCAA supplements.
Are BCAA supplements worth it?
We’ve written about BCAA supplements here before. In a nutshell, no they aren’t… presuming you already get enough protein in your diet.
If you take a look at the research on so-called best amino acids and muscle growth you start to see a pattern… BCAA supplements are only useful when protein intake is very low.
And of course, the question is – why if you’re trying to increase muscle growth are you not getting enough protein in your diet?
A recent (and large) research review conducted by nutrition experts Alan Aragon and Brad Dieter found that BCAA supplements did not boost muscle mass and strength in trained weight lifters.
No benefit whatsoever. None.
The only studies clinging onto the BCAA benefits to increase muscle mass have been circulated around the internet by desperate supplement companies for years.
One in particular claimed that BCAAs helped to slow down muscle loss in a group of active individuals. But get this… they were only eating 80 grams of protein per day.
That’s a stupidly low amount for someone lifting weights!
No wonder supplementation helped them.
Key Point: Bottom line, save your money. BCAA supplements won’t boost muscle growth at all.
Summary – Best Amino Acids for Muscle Growth: Do They Even Exist?
Protein is an important part of the muscle building process. It doesn’t matter how hard you train in the weights room, if you aren’t getting enough protein you won’t optimize the repair processes needed to spark new muscle cells.
Because protein is made up of amino acids, supplement companies have aimed to put two and two together and sell products such as BCAAs as muscle builders. But the research is clear – eat enough protein and you just don’t need them.
Bottom Line: Get your protein from food and save your money. Amino acid supplements such as BCAAs won’t benefit you any more than a healthy diet.
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- Phillips, SM et al. Dietary protein for athletes: from requirements to optimum adaptation. J Sports Sci. 2011; 29 Suppl 1: S29-38
- Breen, L et al. Leucine: a nutrient ‘trigger’ for muscle anabolism, but what more?. J Physiol. 2012; 590(Pt 9): 2065-2066
- Glover, EI et al. Immobilization induces anabolic resistance in human myofibrillar protein synthesis with low and high dose amino acid infusion. J Physiol. 2008 Dec 15; 586(24):6049-61
- Dieter, B et al. The data do not seem to support a benefit to BCAA supplementation during periods of caloric restriction. JISSN. 2016; 13: 21