Amino Acids vs Protein for Muscle Growth

amino acids and proteins

Amino Acids vs Protein, what to choose? Many novice athletes ask this question. However, a blend of a few grams of whey and a few grams of free essential amino acids (EAA) has been proven to have a stronger effect on muscle protein balance than a shake with a reasonable amount of good old whey. This was recently reported by American researchers in the Journal of the International Society of Sports Nutrition.

Concentrated proteins are popular dietary supplements for increasing lean body mass. Protein supplementation can take the form of protein-fortified processed foods or isolated, concentrated proteins. Of the latter, whey protein isolate is the most popular supplement.

Comparing Amino Acids vs Protein

amino acids and protein

EEAs Are Responsible for Stimulating Muscle Protein Synthesis

EAA essential amino acids are the main “active” components of dietary protein. EAAs cannot be produced in the body, but they are primarily responsible for stimulating muscle protein synthesis [1].

Intake of nonessential amino acids, with or without concomitant EAA intake, does not affect protein synthesis in healthy, well-nourished volunteers, whether at rest [1, 2] or after exercise [3, 4].

The response of muscle protein synthesis after ingestion of the EAA composition is more than twice the response to consumption of a comparable dose (g / g) of whey protein isolate [5].

The stronger anabolic effect of the free form of EAA can be attributed to a more rapid increase in plasma concentration of amino acids, as well as higher peak concentrations.

Besides, EAA supplements can be designed to address altered metabolic conditions, such as aging [6].

While EAA nutritional supplements have clear benefits, isolated proteins such as whey protein isolate also have potential benefits.

The reaction of protein synthesis to the consumption of an isolated food protein persists for a longer time than the reaction to the free form of EAA due to the slower assimilation of its constituent amino acids [7].

Also, it has been suggested that peptides produced during the digestion of dietary proteins (especially whey protein) have unique nutritional benefits [8,9,10,11].

Taste preferences can also favor eating isolated protein foods. Thus, the concept of a nutritional composition that combines the beneficial effects of both free form EAA and isolated food protein is attractive.

Leucine and Protein


Previous studies have added free leucine to whey protein isolate to enhance the protein-synthetic response, with mixed results [12, 13].

The rationale behind combining leucine with protein is that leucine can activate molecular mechanisms involved in initiating protein synthesis so that muscle tissue will be more responsive to amino acids from dietary protein.

Although supplementation with free leucine may enhance the acute synthetic response to whey protein, an EAA concentration imbalance is likely to develop in plasma.

Essential amino acids with the lowest concentration concerning the norm will limit the anabolic response, regardless of the size of the excess of other essential amino acids, including leucine.

Therefore, it is important to maintain a balance of EAA that is roughly proportional to the requirement for each essential amino acid. For this reason, the idea of ​​combining a balanced formulation of all EAAs with protein deserves attention.

EEA + Protein

amino acids protein hydrolysis liquid

Don’t Compare Amino Acids vs Protein, Use Them Together

The combination of a balanced EAA formulation and a high-quality concentrated protein should provide the beneficial effect of rapidly and significantly increasing the concentration of leucine to activate protein synthesis at the molecular level, as well as provide enough other essential amino acids to maintain the long-term availability of all precursors necessary for protein synthesis.

In this study, the researchers measured the acute protein kinetics response to two doses of a formulation containing Free Form EAA and Whey Protein, as well as the response to consumption of a popular whey-based protein supplement.

Investigation of the effect of a mixture of EEA and protein on protein synthesis

The study involved 16 healthy men and women not involved in sports. 8 of them took a serving of whey protein isolate containing 12.6 grams of protein. The other 8 took, in one case, a mixture of essential amino acids EAA in free form with whey protein, total weighing 6.3 grams, and in another case the same mixture, twice the dose – 12.6 grams. The composition of the additives is shown in the figure below.

amino acids vs protein

Thus, the effects of pure protein were compared with a protein and EAA blend of equal weight and half the weight of a blend’s serving.

At 4.5 hours on an empty stomach and 4 hours after supplementation, all subjects measured the total anabolic response, or net protein balance (total body protein synthesis minus breakdown).

The second parameter measured was the fractional rate of muscle protein synthesis within 4 hours after drinking. The concentration of amino acids in the blood was also recorded.

Results of the Study of Amino Acid-Protein Mixture (Low EAA)

The researchers saw that within the first 4 hours after the administration of 6.3 grams of Low EAA, muscle protein production increased in much the same way as after 12.6 grams of Whey Protein.

Administration of 12.6 grams of (High EAA) Amino Acid Protein Blend had a significantly bigger muscular effect than whey and half the portion of the blend.

Moreover, a 12.6 g portion of the mixture increased both protein synthesis and significantly reduced its breakdown, which led to almost 6 times greater net protein balance.

protein powder

The change in total EAA concentration after consumption of the formula was directly related to the study product’s dose. Both doses of EAA + protein blend product caused significantly larger increases in EAA concentration than protein alone.

Plasma leucine increased to significantly higher values ​​in both doses of the mixture compared to the protein even though the amount of leucine obtained from a smaller portion of the mixture was less than the amount of leucine in the protein product.

Conclusion: Interactive Effect Between Free Essential Amino Acids and Whey Protein

“We have concluded that there is an interactive effect between free essential amino acids and whey protein, which makes the combination highly anabolic in a dose-dependent manner, which exceeds the anabolic response to a whey protein supplement by about 3 and 6 times for low and high doses of free essential amino acids/protein, respectively,” the researchers write [14].

It should also be added that this study looked at acute reactions to supplements, that is, occurring over a short period of time.

Therefore, it would be interesting to see studies with chronic reactions and, equally interesting, how much the results would change if the larger doses were compared.

12.6 grams of whey protein is half what athletes usually use. Therefore, here we can only say that small portions of protein cause less anabolic response than a mixture of protein with EAA of the same mass.

Sources About Amino Acids vs Protein

  1. Volpi E, Kobayashi H, Sheffield-Moore M, Mittendorfer B, Wolfe RR. Essential amino acids are primarily responsible for the amino acid stimulation of muscle protein anabolism in healthy elderly adults. Am J Clin Nutr. 2003;78(2):250–8.
  2. Tipton KD, Gurkin BE, Matin S, Wolfe RR. Nonessential amino acids are not necessary to stimulate net muscle protein synthesis in healthy volunteers. J Nutr Biochem. 1999;10(2):89–95.
  3. Kato H, Volterman KA, West DWD, Suzuki K, Moore DR. Nutritionally nonessential amino acids are dispensable for whole-body protein synthesis after exercise in endurance athletes with an adequate essential amino acids intake. Amino Acids. 2018;50(12):1679–84.
  4. Davies RW, Bass JJ, Carson BP, Norton C, Kozoir M, Amigo-Benavent M, Wilkerson DJ, Brook MS, Atherton PJ, Smith K, Jakeman PM. Differential stimulation of post-exercise myofibrillar protein synthesis in humans following isonitrogenous, isocaloric pre-exercise feeding. Nutrients. 2019;11(7).
  5. Paddon-Jones D, Sheffield-Moore M, Katsanos CS, Zhang XJ, Wolfe RR. Differential stimulation of muscle protein synthesis in elderly humans following isocaloric ingestion of amino acids or whey protein. Exp Gerontol. 2006;41(2):215–9.
  6. Katsanos CS, Kobayashi H, Sheffield-Moore M, Aarsland A, Wolfe RR. 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;291(2): E381–7.
  7. Churchward-Venne TA, Burd NA, Mitchell CJ, West DW, Philp A, Marcotte GR, Baker SK, Baar K, Phillips SM. Supplementation of a suboptimal protein dose with leucine or essential amino acids: effects on myofibrillar protein synthesis at rest and following resistance exercise in men. J Physiol. 2012;590(11):2751–65.
  8. Tsutsumi R, Tsutsumi YM. Peptides and proteins in whey and their benefits for human health. Austin J Nutri Food Sci. 2014;1(1):1002.
  9. Gaudel C, Nongonierma AB, Maher S, Flynn S, Krause M, Murray BA, Kelly PM, Baird AW, FitzGerald RJ, Newsholme P. A whey protein hydrolysate promotes insulinotropic activity in a clonal pancreatic β-cell line and enhances glycemic function in Ob/Ob mice. J Nutr. 2013;143(7):1109–14.
  10. Saito T. Antihypertensive peptides derived from bovine casein and whey proteins. Adv Exp Med, Biol. 2008;606:295–317.
  11. Athira S, Mann B, Sharma R, Kumar R. Ameliorative potential of whey protein hydrolysate against paracetamol-induced oxidative stress. J Dairy Sci. 2013;96(3):1431–7.
  12. Tipton KD, Elliott TA, Ferrando AA, Aarsland AA, Wolfe RR. Stimulation of muscle anabolism by resistance exercise and ingestion of leucine plus protein. Appl Physiol Nutr Metab. 2009;34(2):151–61.
  13. Churchward-Venne TA, Breen L, Di Donato DM, Hector AJ, Mitchell CJ, Moore DR, Stellingwerff T, Breuille D, Offord EA, Baker SK, Phillips SM. Leucine supplementation of a low-protein mixed macronutrient beverage enhances myofibrillar protein synthesis in young men: a double-blind, randomized trial. Am J Clin Nutr. 2014;99(2):276–86.
  14. Anabolic response to essential amino acid plus whey protein composition is greater than whey protein alone in young, healthy adults. Sanghee Park, David D. Church, Gohar Azhar, Scott E. Schutzler, Arny A. Ferrando & Robert R. Wolfe. J Int Soc Sports Nutr. 2020;17(1):9.
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