Your body can’t produce essential amino acids. They can only be taken in through diet. Although protein can be used for energy, your body prefers to use carbohydrates which get broken down into sugars faster than proteins are broken down into amino acids. So how long does it take for essential amino acids to stimulate protein synthesis? A study published in The Journal of Nutrition found that it takes about 90 minutes.
Researchers had 16 healthy young male subjects consume 15 grams of essential amino acids all at once or in intervals spaced out over a span of 45 minutes. Although the different dosing strategies produced different increases in blood levels of amino acids, muscle protein synthesis was stimulated 90 minutes later in both cases, and this effect continued for 180 minutes after amino acid consumption before returning to normal levels. Now you have a timing strategy to apply to your training.