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Essential amino acids (EAA) · Moderate evidence
What EAAs are for and how they differ from BCAAs
The short answer. EAAs are the nine amino acids the body cannot make, and they are the ones that trigger muscle protein synthesis. Against BCAAs they have a solid argument: three amino acids build nothing, you need all nine. Against a complete protein, however, they add nothing new, because a whey shake already contains them all and costs less per serving.
There are studies in favour, but few, with small samples or measuring markers instead of outcomes. No figure on this page is attributed to a specific product: the effect belongs to the ingredient and every number carries its source next to it.
01 What it does and how much
Each row is a measured effect, with the figure the study gives and the source number. Where the evidence gives no figure, the column says so instead of making up a percentage.
| Effect | How much | Detail |
|---|---|---|
| Dose per serving | ~10 g of EAA | It is the amount that supplies the necessary leucine together with the other essentials. Below it stimulation is weaker, and above it the effect stops growing. [1] |
| Leucine the serving needs | 700 to 3000 mg | Leucine is the switch, but on its own it builds nothing: without the other eight essentials there is no material to make tissue with. [1] |
| Against BCAAs | complete profile | This is the real reason to prefer EAAs to BCAAs. The same review that places BCAAs below a complete protein explains why: six of the nine are missing. [1] |
| Against a complete protein | no advantage | 25 g of whey easily supplies the same essentials and usually costs less per serving. The case for EAAs is convenience or digestion, not efficacy. [1] |
02 How to take it
- Dose. 10 to 15 g per serving, and only if that serving will not include complete protein.
- When. Around training if you train fasted or far from a meal.
- How long before you notice it. There is no acute effect to feel: it counts the same as the day’s protein.
Details that change the result
- Compare the price per serving with that of a complete protein. It is usually three or four times higher for the same job.
- They dissolve in water and do not fill the stomach: that is their real advantage if you train early and a shake does not sit well.
- A product that only declares "amino acids" without saying how many grams of essentials per serving cannot be compared with anything.
- If you already reach daily protein and train after eating, there is no gap to fill.
03 When it makes sense and when it does not
Worth it if
- You train fasted or first thing and a shake does not agree with you.
- A diet with just enough protein that needs a light extra serving.
- Very long sessions where drinking something with amino acids is easier than eating.
Not worth it if
- If you can take complete protein. It does the same and costs less.
- Expecting an anti-catabolic effect during training that reviews do not find.
- Before you have total protein, creatine and rest covered.
04 Sources
Every figure above comes from here. They are position stands from scientific societies, meta-analyses and peer-reviewed reviews: if a claim cannot hang from one of these lines, it is not on the page. References are cited in their original form.
- Jager R et al. ISSN position stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20. La toma debe aportar 700-3000 mg de leucina dentro de un aporte suficiente de aminoacidos esenciales; los BCAA aislados no superan a una proteina completa. doi:10.1186/s12970-017-0177-8
This is not medical advice. It is what some studies say about an ingredient, not a protocol for you. With an illness, medication or pregnancy involved, the decision belongs to a healthcare professional who knows you.
Questions about EAA
Answered with the data on this page
- Are EAAs better than BCAAs?
- Yes, for a specific reason: BCAAs are three amino acids and making muscle protein takes all nine essentials. BCAAs trigger the signal but do not supply the material. That said, any complete protein already carries all nine, so the useful comparison is not EAA versus BCAA, but EAA versus a protein shake.
- How many EAAs should you take?
- About 10 g per serving, which supplies the necessary leucine together with the other essentials. More does not keep increasing the response. And if that serving already includes 25-30 g of complete protein, EAAs add nothing.
- Is it worth taking EAAs if I already take protein?
- Generally not. A whey shake or a meal with complete protein already supplies the nine essentials in abundance and costs less per serving. Where they make sense is practical: fasted training, very long sessions or when a shake feels heavy.
- Do EAAs break a fast?
- They supply calories and amino acids, so strictly speaking yes. If the reason for fasting is the day’s calorie balance, 10 g of amino acids is about 40 calories and changes almost nothing; if the reason is something else, the decision is yours, not a nutritional one.
And now, which to buy
Prices, kept apart from the evidence
This page explains what EAA does and deliberately names no brand. The comparison is the other half: 61 products from 10 stores from €30.98 per kg, sorted by price and by how verifiable their certification is.
Other guides
What each supplement does, with its sources