Building Muscle with Essential Amino Acids

As Moss Nutrition has been emphasizing for years, muscle mass is a major predictor of quality of life, particularly as we age. Loss of skeletal muscle mass, strength, and function underlies the  frailty and physical decline in old age which is associated with chronic diseases and a higher risk of falls leading to disability.1 For this reason, we view preserving and increasing skeletal muscle as a major health goal for all adults.

Muscle tissue is composed primarily of proteins. The anabolic process of building muscle protein is called muscle protein synthesis (MPS). MPS takes place alongside the catabolic process of muscle protein breakdown. Protein turnover liberates the amino acids required to produce all the critical proteins in the body—from enzymes, antibodies and hormones to skin, hair and muscle tissue. The comparative rates of these two complementary processes—muscle protein synthesis and breakdown—determines whether your muscles will grow, shrink, or remain the same in size.

In order for muscle protein synthesis to take place, all nine essential amino acids are required in the proper amounts. Without these building blocks, muscles can not grow or maintain their mass. Studies conducted by Robert R. Wolfe, Ph.D. over nearly two decades has determined the precise ratio of amino acids needed to most effectively and efficiently optimize MPS.2

Beginning in the 1990s with research funded by the National Institutes of Health, Dr. Wolfe and his team determined that in healthy people, only essential amino acids (EAAs) are required to stimulate muscle protein synthesis3 while branched chain amino acids alone had no effect. They discovered that by increasing the proportion of leucine in an EAA blend, the rate of MPS could be increased, notably in the elderly.4 Adding arginine to the EAA mixture led to enhanced gains in lean body mass, strength and physical function, even in patients confined to bed rest.5,6 Often the amino acids were given in conjunction with a simple carbohydrate (sucrose) to promote the desirable anabolic effect of a healthy insulin response.

Strength training is well known to increase muscle mass. Dr. Wolfe’s research shows this mechanism is enhanced when adequate essential amino acids are available for delivery to muscle tissue during exercise. In physically active adult subjects, the greatest MPS gains occurred when the free-form essential amino acid mixture was given just prior to resistance exercise, rather than afterward.7

Dr. Wolfe’s patented blend of nine essential amino acids plus arginine can be found in our new product AminoMeal Select™ —a complete meal replacement and supplement shake available in two tasty flavors, classic Chocolate and fruity Orange-Pineapple. Each serving supplies 3.5 grams of essential amino acids, offering the MPS equivalence of 15-20 g whey or pea protein.


  1. Rizzoli R, et al. Quality of life in sarcopenia and frailty. Calcif Tissue Int. 2014 Aug;93(2):101-20.
  2. Dr. Wolfe is Director of the Center for Translational Research in Aging and Longevity at the Reynolds Institute on Aging, University of Arkansas for Medical Sciences where his research focuses on the regulation of muscle metabolism, particularly as affected by aging and stressors such as injury, sepsis and cancer.
  3. Tipton KD, et al. Nonessential amino acids are not necessary to stimulate net muscle protein synthesis in healthy volunteers. J Nutr Biochem. 1999 Feb;10(2):89-85.
  4. Katsanos CS, et al. A high proportion of leucine is required for optimal stimulation of the rate of muscle protein synthesis by essential amino acids in the elderly. Am J Physiol Endocrinol Metab. 2006 Aug;29(2):E381-7
  5. Borsheim E, et al. Effect of amino acid supplementation on muscle mass, strength and physical function in elderly. Clin Nutr. 2008 Apr;27(2):189-95.
  6. Paddon-Jones D, et al. Essential amino acid and carbohydrate supplementation ameliorates muscle protein loss during 28 days bedrest. J Clin Endocrinol Metab. 2004 Sep;89(9):4351-8.
  7. Tipton KD, et al. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise. Am J Physiol Endocrinol Metab. 2001 Aug;281(2):E 197-206.

By Diana Allen, MS, CNS, Product Development Manager

Moss Nutrition Digest #14 – 09/19/2019 – PDF Version