How Amino Acid Therapy Can Speed Muscle Recovery from Injury and Surgery - Dr. Amino

How Amino Acid Therapy Can Speed Muscle Recovery from Injury and Surgery

Dietary supplements of essential amino acids are the most important aspect of nutritional therapy for recovery from injury or surgery.

Injury and surgery place a similar type of stress on the body, and essential amino acid therapy can help mitigate this stress and accelerate muscle recovery. An essential amino acid supplement with abundant leucine can slow the net loss of muscle protein.

The Similarities Between Injury and Surgery

Think of surgery as a controlled injury. If you are hurt in a car crash, for example, you can go from perfectly healthy to seriously injured in a matter of seconds. The same is often true in the case of surgery—in the case of elective surgery, you are generally feeling good when you are anesthetized, and when you wake up, you feel like a truck ran over you.

Even if an underlying pathological condition necessitates surgery, the surgery itself makes rehabilitation more challenging. Although the exact nature of the stress on the body may differ, how injury and surgery respond to this stress is similar. So, too, are the steps to recovery.

The Catabolic State in Injury and Surgery

Whether you are severely injured or recuperating from surgery, one thing’s for sure—you are going to lose muscle mass and function. It’s inevitable, as recovery requires some degree of inactivity, and inactivity means the muscles aren’t maximizing their movement and performance capabilities. So, a decline is inescapable…but it doesn’t have to be substantial. (We’ll get to that in a moment.)

The detrimental effects of inactivity on muscle mass and function are well established. If you’ve ever had a broken limb put in a cast, you’ve seen the effects firsthand. When it’s time to remove the cast, you’re greeted with the startling withered look of a limb unused…and it’s caused by the loss of muscle, even if you have been working out the rest of your body. An event such as heart surgery that physically limits activity has the same effect as casting a broken limb but on the whole-body level.

Inactivity is just one trigger for muscle loss. Muscle loss is amplified by your body’s overall physiological response to injury, which we call the catabolic state. The catabolic state lasts anywhere from a week or two to months after severe injury.

When we don’t eat enough food, particularly proteins to fuel muscle protein synthesis, the body loses a certain amount of muscle. When your body enters the catabolic state, the loss of muscle mass and strength occurs at a much faster rate than it occurs in the absence of food intake.

You don’t just suffer muscle loss in a catabolic state. Your body also responds with a loss of appetite as well as metabolic changes, such as reduced sensitivity to the action of the hormone insulin. Insulin resistance may persist for months after other symptoms of the catabolic state have resolved.

What Causes the Catabolic State?

The catabolic state following injury or surgery is caused by a variety of factors. The initial response is a flood of stress hormones, most prominently epinephrine, norepinephrine, and cortisol, which activates the sympathetic nervous system. This is known as the fight-or-flight response.

Inflammation also plays a key role in the catabolic response. Inflammation at the injury or surgical site is prominent. Local inflammation plays a beneficial role in the early phase of wound healing, but prolonged local inflammation inhibits tissue repair.

Systemic inflammation, which is long-term chronic inflammation, also contributes to the catabolic state in the whole body, exerting a major impact on muscle loss. To better understand the impact systemic inflammation can have on the entire body let’s use the example of a severe burn injury to the leg. A local response at the site of tissue injury would result in a decline in muscle protein synthesis and a loss of muscle mass and strength to the injured leg. However, a systemic response disrupts muscle protein metabolism just as much in the unburned leg as it does in the leg that sustained the severe burn injury.

Consequences of Muscle Loss in the Catabolic State

Loss of muscle mass and strength after injury or surgery delays recovery and keeps you from returning quickly to normal activity. In severe cases, or in elderly individuals who have little reserve, muscle loss can be a direct contributor to mortality.

In all cases of injury and surgery, the speed and extent of recovery to normal functional capacity is determined in large part by how much muscle has been lost. Injury or surgery causes muscle loss at a rate so fast that consequences can be evident in a matter of days or weeks. If you can decrease the amount of muscle you lose, you can accelerate the time it takes you to recover, and a balanced essential amino acid supplement can help tremendously with that.

What Causes Muscle Loss?

We lose muscle when the rate of muscle protein breakdown exceeds the rate of muscle protein synthesis. Our bodies just can’t make enough new muscle protein to offset the rapid rate of muscle breakdown.

When our bodies enter a catabolic state, the rate of muscle protein breakdown shoots way up. It is not unusual for the rate of protein breakdown to increase by more than threefold!

A large increase in the rate of protein breakdown releases a flood of amino acids into the muscle cells. This increased availability of amino acids stimulates the rate of muscle protein synthesis. Unfortunately, the increased synthesis is not enough to balance the increase in a breakdown. The net result is a large increase in the loss of muscle protein.

Nutritional Therapy with Essential Amino Acids

The biggest therapeutic challenge presented by the catabolic state following injury and surgery is reduced appetite. Loss of appetite makes it difficult to get the protein you need to offset increased muscle protein breakdown and help prevent muscle decline.

Then, there’s the alteration in muscle protein metabolism, which limits the normal stimulatory effect of dietary protein on muscle protein synthesis. The lack of responsiveness of muscle protein synthesis to the normal stimulatory effect of dietary protein is called severe anabolic resistance.

Anabolic resistance in the catabolic state occurs because of a molecular factor called mTOR inside the muscle cell. mTOR activates muscle protein synthesis, but anabolic resistance in the catabolic state decreases mTOR activity. In order for muscle protein synthesis to be further increased in the catabolic state, mTOR has to be activated, which in turn activates other intracellular molecules that are involved in initiating protein synthesis.

So, how do we get mTOR up and running? By supplementing with a complete blend of free essential amino acids formulated with a relatively high proportion of leucine.

Why not get leucine from the diet? Well, for one, appetite is limited in illness and surgery, making it difficult to eat sufficient amounts of leucine-rich dietary protein. Then there’s the fact that free leucine can activate mTOR, while leucine contained in intact protein cannot. This is because free leucine does not require digestion and is therefore absorbed more rapidly. Free leucine reaches a higher peak concentration in blood than when leucine is consumed as part of an intact dietary protein that must be digested before the constituent amino acids can be absorbed.

Once mTOR is activated by leucine, an increased availability of a full balance of all the essential amino acids is necessary to stimulate protein synthesis. Single amino acid therapy with leucine alone, or the three BCAAs, just won’t do it. Thus, although leucine is the key to overcoming anabolic resistance, consumption of leucine alone is not sufficient to stimulate muscle protein synthesis.

In addition to providing precursors for making new muscle protein, if enough essential amino acids are consumed, concentrations will rise high enough to inhibit muscle protein breakdown AND stimulate protein synthesis. So, we can see how essential amino acid nutritional therapy during illness and surgery can help accelerate recovery by protecting against muscle loss. An essential amino acid supplement can:

  • Activate mTor
  • Provide amino acid precursors needed to make new muscle
  • Inhibit the breakdown of muscle
  • Improve the net balance between muscle protein synthesis and breakdown

A stimulation of muscle protein synthesis and inhibition of muscle protein breakdown is the metabolic basis for restoring muscle mass and strength!

To recap: A mixture of free essential amino acids with abundant leucine can slow the net loss of muscle protein, whereas an intact protein in a meal or a meal replacement beverage is ineffective during the catabolic state.

Muscle Recovery and Function

Once the short-term catabolic state passes, your body enters a depleted state marked by significant muscle loss. This will be reflected by significant body weight loss—how many times have you heard that the only good thing about someone’s injury or surgery was that they lost weight?

The lost weight will be gradually regained as recovery continues. However, without diligent adherence to an exercise and nutrition program, the lost muscle weight will be regained as fat. It is crucial to regain the lost weight with new muscle, not fat! Click here, to learn more about gaining “good” weight after a serious illness, injury, or surgery.


Exercise capacity is limited at the outset of recovery. Even so, it is essential to engage in both aerobic and resistance exercise as soon as possible.

Aerobic exercise can take any form—walking, elliptical, cycling, swimming, etc.—that elevates the heart rate to greater than 120 beats per minute. As fitness is regained, speed and the amount of distance covered will increase. Some moderate stretching may also be needed to regain range of motion. As strength returns, work up to the recommended guideline of 150 minutes a week of aerobic exercise. However, because most of your cardio output recovery will be walking as opposed to more strenuous aerobic activity, it’s advisable to increase to five hours per week of aerobic exercise with resistance sessions three times per week.

Resistance exercise is the most important type of exercise for rebuilding muscle. Machines are optimal for resistance workouts, particularly at the outset. The loss of muscle function in the catabolic state impairs coordination, and the possibility of injury is greater with free weights. Machines provide specificity in terms of the muscles involved in any exercise, and this may be of particular importance when addressing specific areas affected by injury or surgery.

The weight lifted should be progressively increased as strength returns. The regain of lost strength is generally faster than the original gain of strength, and the resistance should be adjusted accordingly. A general guideline is to increase the resistance by 10% per week, but progress may be more rapid in the first few weeks of recovery.


Nutrition plays a crucial role in recovery. A balanced diet with ample high-quality protein is essential. However, that is not enough to ensure the regain of more muscle than fat.

Dietary supplements of essential amino acids are the most important aspect of nutritional therapy for recovery from injury or surgery.

Essential amino acids are the active components of dietary proteins. Balanced essential amino acid supplements stimulate muscle protein synthesis to a greater extent than any other naturally occurring protein food source, and with less than half the calories.

Essential amino acid supplements work synergistically with exercise to provide a greater stimulus than either therapy alone. Essential amino acids should be taken 30 minutes before exercise and immediately following exercise to maximize the beneficial effects.

If essential amino acids are consumed without accompanying exercise, the greatest effect will be when taken between meals, but a beneficial impact will be achieved whenever the essential amino acid supplement is consumed.

For more information on a balanced amino acid supplement created for recovery after injury or surgery, click here.

Dr. Robert Wolfe

Robert R. Wolfe, PhD, has researched amino acid and protein metabolism for more than 40 years. His work has been continuously funded by the National Institutes of Health since 1975. He has published more than 550 scientific articles and 5 books that have been cited more than 60,000 times according to Google Scholar.

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