What Happens When You Drink Amino Acids vs. Real Protein?
Ingestion of Free Amino Acids Compared with an Equivalent Amount of Intact Protein Results in More Rapid Amino Acid Absorption and Greater Postprandial Plasma Amino Acid Availability Without Affecting Muscle Protein Synthesis Rates in Young Adults in a Double-Blind Randomized Trial
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Muscle protein synthesis was identical despite 29% greater amino acid availability from free amino acids.
Common belief is that more amino acids in blood = more muscle growth. This study shows the muscle has a 'ceiling'—flooding it doesn’t push it further in healthy young adults.
Practical Takeaways
If you're healthy and eating enough protein, switching to free amino acids won’t give you extra muscle gains.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Muscle protein synthesis was identical despite 29% greater amino acid availability from free amino acids.
Common belief is that more amino acids in blood = more muscle growth. This study shows the muscle has a 'ceiling'—flooding it doesn’t push it further in healthy young adults.
Practical Takeaways
If you're healthy and eating enough protein, switching to free amino acids won’t give you extra muscle gains.
Publication
Journal
The Journal of Nutrition
Year
2022
Authors
Michelle E G Weijzen, Rob J J van Gassel, Imre W K Kouw, Jorn Trommelen, Stefan H M Gorissen, Janneau van Kranenburg, Joy P B Goessens, Marcel C G van de Poll, Lex B Verdijk, Luc J C van Loon
Related Content
Claims (6)
It's not just how fast amino acids show up in your blood after eating — it's how much your body gets over time that might matter more for building muscle.
If you drink a mix of free amino acids instead of whole milk protein, your body absorbs them faster and more of them—especially phenylalanine—show up in your blood over six hours.
If you're a healthy young adult, drinking a supplement with 30 grams of broken-down amino acids won't help your muscles grow more than drinking the same amount from real milk protein—even though your body absorbs the amino acids faster.
If you drink free amino acids, your insulin spikes more after the meal than if you drink the same amount of protein from milk — 35 vs 24 units on average.
If you're a healthy young adult, your muscles might use amino acids from supplements better than from real milk—scientists tracked this by seeing how much labeled phenylalanine ended up in muscle over 6 hours.