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Moderate evidencePhysical performance

EAA (Essential Amino Acids)

EAAs are the scientifically defensible version of BCAAs: all nine essential amino acids do drive muscle protein synthesis, and the classic tracer work shows the non-essential ones are unnecessary. The catch is that whole protein does the same job for less money, so EAAs earn their place mainly when appetite, dose tolerance or protein intake is genuinely limited.

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What the science says

  • Stimulating muscle protein synthesis Strong evidence

    Volpi's controlled trial in healthy elderly adults showed that an essential-amino-acid mixture stimulated net muscle protein balance just as much as a mixture containing both essential and non-essential amino acids, establishing that the EAAs carry the anabolic signal. Acute tracer studies consistently show dose-dependent MPS responses to roughly 10-15 g EAA.

  • Muscle mass and strength in older adults Moderate evidence

    A 2018 systematic review and meta-analysis of protein and amino acid supplements in older adults with acute or chronic conditions found small but significant improvements in body weight and some functional measures, with effects clearest where baseline intake was inadequate. Benefits shrink toward zero in older adults already meeting protein targets.

  • Superior to whole protein for building muscle Limited evidence

    Head-to-head trials do not show free EAAs outperforming an equivalent EAA dose from whey or other complete protein over training periods. EAAs are absorbed faster, but faster is not better once total daily protein is adequate; the practical advantage is volume, not efficacy.

Dosage & safety

Studied doseAcute studies use 6-15 g EAA (containing roughly 2-3 g leucine) per serving; chronic trials in older adults typically give 7.5-15 g twice daily between meals. Taking EAAs between meals rather than with a protein-rich meal is what most trials did.
SafetyWell tolerated; GI upset and unpleasant taste are the usual complaints. Free amino acids raise blood urea, so people with significant kidney or liver impairment should consult a clinician. Contraindicated in phenylketonuria (phenylalanine content) and in maple syrup urine disease. Not banned in sport, but as with any powdered sports supplement, tested athletes should choose third-party certified products.

How to take it

TimingBetween meals, which is when the trials dosed it and when a free amino acid load actually adds something.
With food?On an empty stomach or between meals; taking it with a protein-rich meal defeats the purpose.
Worth knowingCheck the leucine content per serving — under about 2 g and the product is unlikely to do what the trials did.

Frequently asked questions

Do EAAs build muscle?

Yes — the evidence is strong that essential amino acids (EAAs) drive muscle protein synthesis, with dose-dependent responses to roughly 10–15 g. But whole protein does the same job for less money.

Are EAAs better than whey protein?

No — the evidence is limited. Head-to-head trials show free EAAs do not outperform an equivalent EAA dose from whey or other complete protein; EAAs mainly help when appetite or protein intake is limited.

How much EAA per serving, and when?

Studies used 6–15 g of EAAs per serving with roughly 2–3 g of leucine, usually between meals. Check the leucine content, since under about 2 g an EAA product is unlikely to match the trials.

Do EAA supplements help older adults keep muscle?

Moderately: a meta-analysis found protein and amino acid supplements such as EAAs gave small gains in older adults with acute or chronic conditions, clearest when baseline intake was inadequate.

Scientific references

Where to buy

Swanson Vitamins, Essential Amino Acid Complex, 60 Vegan Capsules

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