Best Amino Acids for Muscle Growth

  • By Abigail Roberts
  • 5 minute read
Best Amino Acids for Muscle Growth

Whether you’re a bodybuilder, CrossFitter, or a recreational weightlifter, training to increase your muscle mass is the foundation of any fitness programme.

Improved posture, increased strength, and boosted energy levels are among many of the health benefits of being more muscular, which can enhance your quality of life and training performance as a result.1

However, building muscle is no easy feat. It requires patience, consistency, and knowledge, as well as an effective and personalised nutrition, training, and supplement plan to achieve the best results.

With supplements in mind, there are a wide range of sports supplements available, many of which claim to be the key to muscle growth.

The sports supplement world can be a bit of a minefield to navigate at times, though in this article we talk about the actual key to muscle growth - amino acids - and which are the best ones for optimizing your gains!

Firstly, let’s go over a quick overview of what amino acids are.

What Are Amino Acids?

Protein is one of the three macronutrients, or “macros”, along with carbohydrates and fat, that provide us with energy.

Each macronutrient plays a different role in the body, though for now we will focus on protein.

Protein provides our body with amino acids, which are the building blocks for muscle and other important structures such as skin, hair, nails, our nervous system and brain, and blood.

There are 20 amino acids in total, and our body naturally produces 11 of them. This means that there are 9 amino acids that our body can’t make (known as “essential amino acids”), which means we must consume them through our diet.

Three key essential amino acids include leucine, isoleucine, and valine, otherwise known as the branched chain amino acids (BCAAs). We will go into more detail about these soon!

Before we do, it’s important to understand how muscle growth works so you can better understand the role amino acids play in growing muscle.

Muscle Growth 101

There are 3 key principles you need to consider when building muscle:

1) Protein intake

Protein is an essential nutrient for muscle building, and the quality, quantity, and timing of protein is key!

The main points to consider would be:

  • Getting enough daily protein to support muscle building (1.6-2.2g per kg bodyweight)
  • Consuming high-quality sources such as meat, fish, dairy, eggs, and soy
  • Eating protein in regular feedings (every 3-4 hours) to optimize muscle protein synthesis - the process of building and repairing muscle.2

As we have established, amino acids are the building blocks of protein, and paying closer attention to BCAAs may help optimize your muscle growth - more on this in the next section!

2) Energy (calories)

It takes a lot of energy to build muscle, so our body needs an adequate intake of calories to support these needs.

Receive unique insights, advice and exclusive offers.
image of Performance Lab® capsules

You can achieve this through a positive energy balance (a calorie surplus). A small to moderate calorie surplus is often recommended, around 10-20% above maintenance calories.2

For example, if your maintenance calories are around 2000kcal, you’d ideally need an extra 200-400kcal per day to meet the energy requirements for building muscle.

3) Training programme

Progressive overload is considered one of the major factors of muscle growth, so it’s essential to have an effective program that is based on this principle with a strong focus on stimulus.3

Follow an effective and consistent resistance training programme to maximise your gains.

BCAAs: The Best Amino Acids for Muscle Growth

Branched-chain amino acids (BCAAs) are made up of the 3 amino acids: leucine, isoleucine, and valine. The BCAAs make up around one-third of the protein found in muscle.

The BCAAs play a key role in muscle protein synthesis (MPS), which is the process of repairing and rebuilding muscle.4

You can find BCAAs in high levels in animal protein such as meat and dairy, and also through supplementation, which has been shown to have a significant impact on the body’s ability to grow muscle and optimize recovery from training.4

Let’s take a closer look at the benefits of BCAA supplementation!

The Benefits of BCAA Supplements

BCAAs for Increasing Muscle Growth

The main benefit of BCAA supplementation is to help increase muscle growth.

Leucine, one of the 3 BCAAs, plays one of the most important roles when it comes to stimulating muscle protein synthesis, the process of making muscle.

Leucine is known to be the nutrient trigger for muscle anabolism. It has been studied more extensively than the other two BCAAs, particularly around its effect on muscle protein synthesis.5

Combining BCAAs with adequate daily protein intake has been shown to maximize muscle growth and repair, which is why it’s a top pick among athletes and gym-goers alike.

BCAAs for Improving Muscle Recovery & Athletic Performance

Have you ever suffered with sore muscles, or delayed onset muscle soreness (DOMS), after a tough workout?

Need some help with faster recovery before your next workout?

BCAAs have been shown to reduce muscle soreness following intense weight training sessions.

Once again, combining BCAA supplementation with adequate daily protein and energy intake has been shown to help relieve muscle soreness, thus resulting in quicker recovery rates and improving your ability to perform to your maximum potential.4

BCAAs for Preserving Lean Muscle Mass

You may have heard of BCAAs being useful for those currently in a fat loss, or “cutting”, phase, i.e., a calorie deficit.

BCAAs are thought to have the ability to enhance muscle protein synthesis and reduce muscle breakdown, which in turn would help preserve muscle mass.

This is particularly effective for those who are intending to train in a fasted state, or for those in an energy deficit.

Being in an energy deficit or training fasted may compromise your lean muscle mass, as without sufficient energy stores, your body would look to breakdown the protein in muscles so it can be used as fuel.

Supplementing with BCAAs before and during a workout is thought to help combat this process by preventing muscle breakdown.4

BCAAs for Optimizing Low Protein Meals

As we have discussed, BCAAs may provide support for muscle growth, muscle repair and recovery, and optimizing performance alongside adequate protein and energy intake.

Though, have you thought about the benefits of BCAA supplementation from a nutritional standpoint?

For anyone who follows a plant-based diet, you know how tricky it can sometimes be to consume sufficient sources of protein throughout the day.

As animal protein is not an option for this population, they may fall short of some key amino acids.

Enter BCAA supplements!

Consuming BCAAs around certain low protein meals has been shown to optimize the amino acid profile, thus helping to ensure you raise your muscle protein synthesis rates.4

So, not only do BCAAs come in handy around your workouts, but they can also help balance out a low protein meal to ensure you’re getting the key muscle-building amino acids!

BCAAs: When to Take

Timing your BCAA supplementation can be a smart strategy!

In general, you can take BCAAs at regular intervals throughout the day, or as we have discussed, as an addition to a low protein meal.

However, here are some specific timing strategies to consider:

BCAAs Before & During a Workout

Taking BCAAs before and/or during a workout may be beneficial in maintaining and preserving your lean muscle mass.

Additionally, it may help to prevent muscle fatigue, allowing you to train harder for longer, particularly for endurance-based sessions, or if you’re in a fasted state.4

BCAAs After a Workout

Consuming BCAAs after your workout will help restore and replenish tired muscles, thus allowing you to recover faster and more efficiently in time for your next session.4

Take-Home Message

There are many sports supplements currently available that claim to help you build muscle, including amino acids.

Once you’ve dialled in the fundamentals of muscle growth (calories, protein, and training), you should consider amino acids to optimize your gains.

The best amino acids for muscle growth are the branched-chain amino acids (BCAAs), which have been extensively studied and have been shown to help optimize muscle growth, preserve lean muscle mass and maximize muscle recovery after training.


  1. Suchomel TJ, Nimphius S, Stone MH. The Importance of Muscular Strength in Athletic Performance. Sports Med. 2016 Oct;46(10):1419-49. PMID: 26838985.
  2. Iraki J, Fitschen P, Espinar S, Helms E. Nutrition Recommendations for Bodybuilders in the Off-Season: A Narrative Review. Sports (Basel). 2019;7(7):154. Published 2019 Jun 26.
  3. Krzysztofik M, Wilk M, Wojdała G, Gołaś A. Maximizing Muscle Hypertrophy: A Systematic Review of Advanced Resistance Training Techniques and Methods. Int J Environ Res Public Health. 2019;16(24):4897. Published 2019 Dec 4. 
  4. K. Patel. Branched-Chain Amino Acids. 2020
  5. K. Patel. Leucine. 2019