Your body works hard during training. An intra-workout supplement that contains a high concentration of amino acids maximizes those efforts and accelerates your progress.
How? Intra-workout supplementation takes effect at the exact time your body needs it. During exercise, blood flow to your muscles and nutrient absorption are at an all-time high.
When consumed as an intra-workout supplement, amino acids promote muscle building and fights muscle breakdown. This means you’ll see improvements in both performance and recovery.
But creating the best intra-workout supplement is a matter of individual goals, preferences, and priorities.
Here, we’re breaking down the different types of amino acids, their sources, and dosage guidelines, so you have all the information you need to build your optimal intra-workout supplementation plan.
Which amino acids should I take intra-workout?
Even as healthy adults, our bodies cannot make the nine classified essential amino acids (EAAs) so we need to rely on our diets to get them. Included within these nine EAAs is the branched-chain amino acids (BCAAs)—leucine, valine, and isoleucine.
If you’ve done any reading on the topic, you’ll find plenty of conflicting information about whether you should take just the BCAAs or the full spectrum of all nine EAAs.
Related: Why Intra-Workout Supplementation Works
BCAA advocators believe that athletes already consume plenty of protein, whether it’s from food or supplements, so additional EAAs are not necessary. They support only taking the BCAAs, particularly leucine, during workouts.
But EAA advocators question this stance, wondering why BCAA advocators recommend taking the other two BCAAs (valine and isoleucine) at all if leucine is the key amino acid responsible for stimulating protein synthesis (muscle building). Using leucine alone yields the same stimulus results as taking all three BCAAs, so a middle-ground stance of taking just the three BCAAs doesn’t make sense.
Here are the facts: Research has found that taking all nine EAAs may allow for a longer stimulus on protein synthesis than just taking the BCAAs alone. To gain the largest and longest protein synthesis, include all nine EAAs in your supplement. Based on scientific research, this approach will maximize the benefits of your intra-workout supplementation.
One exception to note: Emerging research shows that under extreme training conditions, our bodies may need nonessential amino acids (NEAAs) in order to sustain elevated levels of muscle protein synthesis.
Previous research has found that those who took whey protein, which contains both EAAs and NEAAs, experienced an elevated rate of muscle protein synthesis for three to five hours post-exercise, while those who just took the EAAs kept muscle protein synthesis elevated for only one to three hours.7
Given these findings, there is a strong, growing case that taking EAAs and NEAAs together from whey is superior to taking just the EAAs, and certainly superior to taking just the BCAAs.
Which sources of amino acids provide the most benefits?
To optimize the effects of your intra-workout supplement without upsetting your digestive tract, focus on hydrolyzed protein and free-form amino acids. As a distant third, consider your general protein powders.
Let’s explore the pros and cons of these different sources:
Whey is currently the best source of protein that has been hydrolyzed (enzymatically broken down) into rapidly absorbing di- and tripeptides.
Peptides are chains of two or more amino acids. Your body can absorb the shortest peptides rapidly and without any digestion needed. Any peptide longer than tripeptide requires digestion to break it down to either a dipeptide, tripeptide, or a single amino acid, before it can be absorbed into the blood.
It pays to check labels. If it states the percentage of di- and tripeptides, aim for a significant amount in the 30 to 50 percent range or more.
- Our bodies' small intestines are naturally designed to absorb di- and tripeptides intact, so no digestion is required. Absorption is quick and easy without stomach or gastrointestinal (GI) tract discomfort.
- Hydrolyzed protein contains both EAAs and NEAAs.
- When mixed with water, it has a very thin, easy-to-drink consistency.
- Di- and tripeptides may actually enhance free-form amino acid transporters, further increasing the rate of absorption and creating a higher spike of amino acids in the blood during your workout.
- Very few protein hydrolysates in the market contain any significant amount of di- and tripeptides—and the few that do are usually very expensive.
- Di- and tripeptides can taste bitter, so it’s a challenge to flavor products so that they taste appealing.
Free-form amino acids
You’ll know that a product contains single free-form amino acids if its label lists amino acids but doesn't note a protein source, such as whey, egg, or plant.
Related: Peri-Workout Supplements - Complete Pre, Intra & Post-Workout Guide
- Our bodies' small intestines house a specific transporter to absorb single free-form amino acids, leading to rapid absorption into the blood without GI distress.
- Ingesting free-form amino acids causes an almost immediate spike in amino acids that can last up to 90 minutes.
- Due to their rapid absorption and subsequent spike in the blood, free-form amino acids produce a rapid spike in protein synthesis stimulus (muscle building).
- They can be mixed into water and maintain a very thin consistency, making them easy to drink during an intense workout.
- Free-form amino acids do not contain the NEAAs.
- These can be more expensive than intact proteins, such as whey, egg or soy.
- Free-form amino acids are more difficult to flavor than intact proteins.
Intact protein sources
Intact protein sources include regular whey protein concentrate, isolate, milk, egg, casein, soy, and other plant-based proteins. Intact means the proteins are in long chains of amino acids called polypeptides, which must be broken down into shorter di- and tripeptides and free-form amino acids before our bodies can absorb them from the small intestine into the blood.
- Intact protein sources contain all of the EAAs and NEAAs.
- They are inexpensive compared to hydrolyzed proteins and free-form amino acids.
- They're easy to flavor and usually taste good.
- Whey protein in particular has the highest amount of EAAs, along with the lowest amount of NEAAs. More specifically, it has the highest naturally occurring amounts of the beneficial amino acid leucine (typically 10 percent).
- Intact protein sources require digestion prior to absorption.
- More time is required before amino acids start appearing in the blood in significant concentrations.
- The required digestion and slower release of amino acids into your blood may limit the acute protein synthesis (muscle building) response.
- They mix into water with a thicker consistency than free-form amino acids or di- and tripeptides, making them impractical to drink during your workout.
What is the optimal dose of essential amino acids?
For the maximum protein synthesis stimulus, anti-catabolic, and recovery benefits, utilize the dosage ranges outlined below for your intra-workout supplementation. Be sure to take into account the source you choose and the amount of essential amino acids it naturally contains. You can use single sources or combine multiple sources to reach these numbers.
- 6-15 grams of essential amino acids
- 3-5 grams of the amino acid leucine, the most important stimulating protein synthesis amino acid
Related: Should I Take High Molecular Weight Carbs During My Workout?
Example (lower end of the dosing spectrum, combined sources):
- Free-form amino acids: 5 g, with 2.5 g coming from leucine
- Whey protein: 5 g, providing 2.0-2.5 g of EAAs and 0.5-0.7 g coming from leucine
- Total EAAs provided: 7 g, with 3 g of leucine making up the majority
Example (upper end of the dosing spectrum, combined sources):
- Free-form amino acids: 10 g, with 5 g coming from leucine
- Whey protein: 10 g, providing 4.5-4.9 g of EAAs and 1.0-1.4 g coming from leucine.
- Total EAAs provided: 14-15 g, with 6 g of leucine making up the majority
If you use single sources of protein without the addition of free-form amino acids to reach the optimal amounts of EAAs and leucine, follow these guidelines:
- 25-30 g needed
- 44-49% EAAs
- 10% leucine
RICE PROTEIN POWDER
- 44 g needed
- 35-37% EAAs
- 8% leucine
SOY PROTEIN ISOLATE
- 44 g needed
- 35-37% EAAs
- 8% leucine
- 40 g needed
- 42% EAAs
- 8% leucine
MILK PROTEIN ISOLATE
- 30-35g needed
- 42% EAAs
- 10% leucine
You’re willing to work hard to achieve your training goals and you know the best things in life take time, effort, and commitment. To maximize your progress and performance, rely on scientifically sound strategies like optimal intra-workout supplementation. Building a nutrition plan that aligns with your priorities and preferences means you’ll gain the edge you need to succeed.
- Ferrando, Arny A PhD1; Tipton, Kevin D PhD2; Wolfe, Robert R PhD1 Essential Amino Acids for Muscle Protein Accretion. Strength & Conditioning Journal: February 2010 - Volume 32 - Issue 1 - pp 87-92
- Tipton KD1, Rasmussen BB, Miller SL, Wolf SE, Owens-Stovall SK, Petrini BE, Wolfe RR. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise. Am J Physiol Endocrinol Metab. 2001 Aug;281(2):E197-206.
- Wolfe RR1. Skeletal muscle protein metabolism and resistance exercise. J Nutr. 2006 Feb;136(2):525S-528S.
- Bohé J1, Low A, Wolfe RR, Rennie MJ. Human muscle protein synthesis is modulated by extracellular, not intramuscular amino acid availability: a dose-response study. J Physiol. 2003 Oct 1;552(Pt 1):315-24. Epub 2003 Aug 8.
- Beelen M1, Koopman R, Gijsen AP, Vandereyt H, Kies AK, Kuipers H, Saris WH, van Loon LJ. Protein coingestion stimulates muscle protein synthesis during resistance-type exercise. Am J Physiol Endocrinol Metab. 2008 Jul;295(1):E70-7.2007. Epub 2008 Apr 22.
- Paddon-Jones D1, Sheffield-Moore M, Aarsland A, Wolfe RR, Ferrando AA. Exogenous amino acids stimulate human muscle anabolism without interfering with the response to mixed meal ingestion. Am J Physiol Endocrinol Metab. 2005 Apr;288(4):E761-7. Epub 2004 Nov 30.
- Slow and fast dietary proteins differently modulate postprandial protein accretion. Boirie Y1, Dangin M, Gachon P, Vasson MP, Maubois JL, Beaufrère B. Slow and fast dietary proteins differently modulate postprandial protein Proc Natl Acad Sci U S A. 1997 Dec 23;94(26):14930-5accretion.