How Amino Acids Help Your Muscles Recover from Workouts

by Sukhsatej Batra, Ph. D September 03, 2020

Exercising to stay fit is on the top of your list and as a fitness enthusiast, you have an arm length list of resistance exercises to maintain health, boost endurance, and improve muscle strength. You know that resistance training workouts are a great way for building and maintaining muscles, burning calories, weight loss, strengthening bones, increasing energy levels, and generally lift your mood. It is, however, the sore, aching muscles after the workout that keep you awake and make you think twice before going for resistance exercise again.

From reading what sports nutrition and sports medicine experts say about muscle soreness, you know that you need to increase protein intake in the form of protein powder and whey protein for muscle protein synthesis and that some amino acids are more effective than others in post-workout recovery. You wonder, are amino acids good for muscle recovery? Do amino acids build muscle? But the first question you may very well have is why resistance exercises cause muscle soreness? Let us look at what happens when you go for resistance training and how amino acids help your muscles recover from workouts.

Muscle Soreness

You probably do resistance training workouts to build muscle strength, increase muscle endurance, tone muscles, build bigger muscles, and lose body weight. Some common resistance exercises that you may do are squat exercises, push-ups, chin-ups, body planks, lift weights, use weighted bags, weight machines and resistance bands. About 24 to 48 hours after going through your high-intensity and strength training exercise routine you may experience onset muscle soreness, also called delayed onset muscle soreness or DOMS. Symptoms of DOMS may be mild, with a feeling of muscle tenderness and general aches and pains. However, intense symptoms of DOMS may cause muscle stiffness and unbearable pain that make any kind of movement difficult. (1)

Muscle soreness or DOMS is caused by the repetitive action of resistance exercises as your skeletal muscles contract frequently during the duration of your routine. The recurring movement leads to inflammation and microdamage or tearing of muscle fibers, both of which onset muscle soreness and lead to post-exercise muscle tissue damage. (2)

What your body needs after the onset of muscle soreness and muscle protein breakdown is time for muscle repair and recovery so that muscles can heal and muscle growth can take place. While most symptoms of muscle soreness disappear within 7 days, it important to aid muscle recovery as quickly as possible. If care is not taken, delayed onset muscle soreness not only lowers morale and exercise performance but also the inclination to continue working out. (1,2)

Muscle Recovery

Muscle recovery occurs from the inside and outside. The body repairs muscle damage by the anabolic or building process, resulting in the re-growth of muscle tissue. Stretching, anti-inflammatory supplements, electrical stimulation or cryotherapy can be used to recover from muscle soreness. Amino acid supplements, however, are the most common method used to boost muscle recovery and aid in muscle protein synthesis after damage to muscles. (1)

Amino acids are the building blocks of protein, with 20 different amino acids making up all the different kinds of proteins in the body. Of these amino acids, nine amino acids are essential (also called essential amino acids or EAA) for humans and need to come from food as they cannot be made by the body. The rest are nonessential amino acids because they can be produced by the body. During sickness or extreme stress, some of the non-essential amino acids become conditional amino acids that need to come from food because they cannot be synthesized in the body. (3)

Branched-Chain Amino Acids or BCAA

Of the essential amino acids or EAA, three amino acids, leucine, isoleucine, and valine, have a branched chemical structure and are called branched-chain amino acids or BCAA.

These essential amino acids play a role in promoting repair, building muscle and even help muscles grow faster in some situations. Branched-chain amino acids are found in protein-rich food like eggs, meat, poultry, dairy products and are also available as dietary supplements. 

There is evidence that branched-chain amino acid supplementation has an anabolic effect on muscles and decrease muscle damage experienced after exercising. This effect is attributed to the fact that BCAAs are unique and, unlike other EAAs, they do not need to be broken down in the liver but are taken up directly by muscles. BCAA supplements can thus help muscles recover from workouts quickly by reducing muscle soreness, promoting protein metabolism and increasing muscle mass. (2)

BCAAs Decrease Muscle Soreness

As described above, you may experience muscle soreness a day or two after performing resistance exercises. While the cause of sore muscles is complex, it is thought to be mostly caused by inflammation and tiny tears or microdamage in muscle fibers. Muscle damage decreases muscle function, causes discomfort, and discourages you from exercising. Apart from muscle soreness, strenuous exercise also increases blood creatine kinase (CK) levels. (1)

Taking BCAA supplements before and after exercise may help reduce muscle damage during exercise, decrease whole body protein breakdown and decrease the intensity of muscle soreness.

Studies have shown that intensity of muscle soreness was significantly lower in participants who took BCAA supplements as compared to the placebo group. (1,2,4) In one study, trained volunteers were given either a placebo or BCAA supplement before and after performing 100 consecutive drop-jumps, which is considered as damaging exercise. Participants who took BCAA supplements had lower CK levels and muscle soreness compared to the placebo group.(5)

Another study found that BCAA supplementation decreased creatine kinase (CK levels) and lactate dehydrogenase (LDH levels) after exhaustive exercise, suggesting that BCAA reduced muscle damage linked with intense exercise. (6)

BCAAs Increase Muscle Growth

Another way that branched chain amino acids helps muscle recovery is by rebuilding muscles that are torn during exercise. While all branched amino acids are involved in skeletal muscle protein synthesis, the branched-chain amino acid, leucine, seems to have a greater effect on mTOR pathways that regulate protein synthesis and cell growth. This may speed up the process of muscle growth and therefore decrease the severity and duration of muscle soreness. (1)

A study involving resistance trained men found that those who consumed 5.6 grams of BCAA after exercise had a 22% increase stimulation of protein synthesis as compared to the placebo group. (7)

BCAAs Delay Onset of Fatigue

Fatigue or the feeling of tiredness you experience when you exercise can also be delayed after taking BCAA supplementation. There are two ways you get tired during a workout – one is peripheral fatigue when your muscles get tired, and the other is central fatigue, which happens when your brain gets tired. Central fatigue is the reason most people stop exercising. (8)

Remember the feeling of lethargy and sleepiness you experienced after the turkey thanksgiving dinner? You have probably heard that the relaxed, sleepy feeling is because of an amino acid called tryptophan that is present in turkey. Well, exercise also increases levels of tryptophan in your blood. Increased levels of tryptophan mean that your body can produce more of a hormone called serotonin, which causes central fatigue. The feeling of tiredness, lethargy and loss of motor coordination you experience after working out for some time is because of higher levels of serotonin. BCAA supplements before exercise may reduce levels of tryptophan and lower production of serotonin that can ward off central fatigue. (2,8)

A recent study found that long-distance runners who took 20 grams of BCAA before exercising on a treadmill were able to work out for a longer time as compared to those on a placebo. The BCAA supplemented group has lower levels of plasma serotonin compared to the placebo group, indicating that it took them longer to be fatigued.(9) The explanation behind this is that in the presence of BCAAs, tryptophan uptake by the brain is decreased, which in turn reduces synthesis of serotonin and therefore delays the onset of fatigue. (10)

Take home message

BCAA supplementation may be beneficial for you if you are an athlete looking to improve your athletic performance or an individual who constantly engages in prolonged exercise. BCAA supplements can also help build endurance by decreasing the onset of central fatigue, preventing muscle tissue breakdown, improve muscle mass, and aid in decreasing time for muscle building, muscle recovery after resistance training. 


Sukhsatej Batra, Ph. D
Sukhsatej Batra, Ph. D

Sukhsatej Batra has a Ph. D in Foods and Nutrition with a passion for motivating people to improve their well-being and achieve results through healthy lifestyle changes. Previously, Sukhsatej has worked as a Senior Research and Development Scientist and college professor.

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