When to Take Amino Acids for Muscle Growth

Amino acids are popular amongst athletes and anyone looking to improve their performance in the gym, especially those training to increase their muscular strength. While there is definitive agreement about the importance of protein & amino acid (AA) consumption, there is still some debate about when to take amino acids as supplements.

Some people believe taking amino acids before a workout is best, while others prefer to take amino acids as a recovery supplement after a workout. This article discusses the timing of amino acid consumption, essential amino acid (EAA) and branched-chain amino acid (BCAA) supplements, benefits, and ideal dosage.

When to take amino acids

The recommendations for the timing of EAA and BCAA supplements are similar. In general, there is limited research and mixed results, with some studies indicating enhanced benefits of taking amino acids before training and others showing better results from taking amino acids after training.

Overall, taking amino acids before, during, or after training will promote improved muscle strength, hypertrophy, and positive body composition changes regardless of the timing (1).

It appears ideal to take amino acids within 30 minutes before exercise to prevent muscle catabolism and damage during exercise, provide a source of energy to the muscles, and stimulate muscle protein synthesis (2, 3). Taking amino acids after exercise, within 2 hours, will also stimulate muscle protein synthesis, but may have less effect on preventing muscle breakdown (4).

What are amino acids?

Amino acids are small molecules that bind together to form proteins. When we consume foods with protein, the protein chains are broken down into amino acids during digestion. The body then takes the individual amino acids and combines them as needed for different functions.

The body doesn’t store amino acids, so it requires a consistent daily supply to perform the many functions that keep us alive and healthy. Because of this, amino acid supplements can be an easy way to support people who have difficulty eating enough protein each day or have high protein needs due to their fitness goals and exercise regimens.

Types of amino acids

• Essential amino acids: a group of nine amino acids that the body can’t make, so we must get them from food
  • Foods that contain all nine EAAs in sufficient quantities are considered complete proteins; examples include meat, fish, eggs, dairy, soy, buckwheat, and quinoa
  • Foods that don’t contain all nine EAAs in sufficient quantities are considered incomplete proteins; examples include beans, seeds, nuts, and grains
  • Branched-chain amino acids: three of the nine EAAs – leucine, isoleucine, and valine – which are unique in their structure and function and play a role in muscle-building
    • Foods with the most BCAAs include eggs, chicken breast, lean beef, canned tuna, salmon, flank steak, tilapia, and turkey breast
    • About 35% of the BCAAs in the human body are found in muscle tissue
• Non-essential amino acids: a group of eleven amino acids that the body makes, so we usually don’t need to consume them from food unless our need for them is greater, as mentioned below
  • Conditionally essential amino acids: a group of amino acids that the body can make but may require additional amounts of during times of stress, like injury, illness, surgery, pregnancy, or high-intensity physical activity
    • During times of stress, we need to consume these amino acids from food to meet the increased need

What do amino acids do?

Amino acids are involved in many actions in the body including the following:

• Digesting food
• Creating hormones, neurotransmitters, and enzymes
• Repairing and growing new muscle
• Repairing organs and tissues
• Promoting immune system function
• Providing structure to skin, hair, and nails

Benefits of amino acid supplements

Amino acid supplements contain free amino acids which don’t require digestion. They are quickly absorbed in the small intestine and then sent to the blood for your cells to use. Within 5-30 minutes after consumption, your body can use the amino acids, which makes these supplements useful for exercise sessions.

Essential amino acid supplements

• Contain all 9 EAAs to optimally support various functions in the body
• Increase anabolic response to resistance training, including muscle protein synthesis (MPS) which is the process that promotes muscle growth
• Help maintain and grow muscle mass by creating a positive protein balance, thereby decreasing the chance that muscle will be broken down for energy
• May increase MPS more than supplementing with BCAAs alone (4)

Branched-chain amino acid supplements

• Reduce general fatigue during exercise (5)
• Increase muscle growth by stimulating MPS
• Decrease muscle breakdown by providing energy to the muscles during exercise once the available blood glucose is used up
• Speed muscle recovery and decrease muscle damage (4, 6)
• Minimize delayed-onset muscle soreness (DOMS) (3, 7, 8)
• Improve immune system response to exercise
• Reduce sarcopenia, which is the loss of muscle mass and is common in older people

Who should take amino acid supplements?

The following groups of people may benefit from supplementing with amino acids:

• People who have difficulty eating sufficient protein from food sources
• People who don’t eat animal products, such as those following a vegetarian or vegan diet
• People with increased protein needs, i.e. when healing from injury or illness or performing increased physical activity
• People who don’t eat at least three meals per day and want to ensure they have a consistent supply of EAAs throughout the day to maximize MPS
• Athletes or people engaging in resistance training; BCAA supplements contain a higher concentration of leucine, isoleucine, and valine than other amino acid supplements and may be more targeted for muscle growth and recovery due to the additional leucine (9)

What is the best dose of amino acids?

• 6-12 grams of EAAs in supplement form per day will maximally stimulate MPS
  • This amount equates to ~15-30 g of whole food protein (4)
• 5-10 grams of BCAAs in supplement form per day will maximally stimulate MPS
  • 3-6 grams of leucine per day may prevent muscle catabolism and promote muscle gain (4)

How to maximize the benefits of taking amino acids

• Take amino acid supplements daily, rather than only on training days
• Divide your amino acid dose into 2-3 throughout the day to provide your body with a gradual delivery of amino acids (10)
• If you prefer to consume your supplement around the time of your workout, taking amino acids 30 minutes before exercise and within 2 hours after exercise will help maximize the effectiveness
• Pair your amino acid supplement with a quick-digesting carbohydrate source before exercise for greater energy availability and increased muscle protein synthesis (2)

Final thoughts

While consuming adequate protein throughout the day is the most important factor for building muscle and maintaining your health, essential amino acid and branched-chain amino acid supplements can help to maximize your results.

The greatest benefits are seen when taking amino acids immediately before and after exercise. This supplies your muscles with fuel, helps prevent muscle breakdown and damage, stimulates muscle protein synthesis, and supports recovery.

If you already consume adequate protein from a variety of sources throughout the day, BCAAs may be all you need to see results. However, if you tend to go several hours between meals or snacks or have difficulty eating enough protein, EAAs may be the better option for you.

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