EAA Dosing Guide — How Much, When, and Why It Matters

The short answer: dose and timing both matter, but dose matters more.

How much: the dose-response relationship

Muscle protein synthesis doesn’t respond to EAAs in a linear, “more is always better” fashion. There’s a dose-response curve with a practical ceiling.

The threshold dose: Cuthbertson et al. (2005) showed in FASEB Journal that an oral dose of 10g of essential amino acids maximally stimulated protein synthesis, with dose-dependent effects up to that point. Moore et al. (2009) confirmed in the American Journal of Clinical Nutrition that approximately 20g of intact protein (containing ~10g EAAs) is sufficient to maximally stimulate MPS after resistance exercise — beyond which additional protein is oxidized rather than used for synthesis.

Above the ceiling: The “muscle full” effect, described by Atherton et al. (2010) and Bohé et al. (2001) in the Journal of Physiology, shows that MPS peaks within about 1.5–2 hours of amino acid elevation and then returns to baseline despite continued availability. The synthetic machinery saturates regardless of additional substrate.

Practical recommendation: For most adults, 10–12g of EAAs per serving hits the sweet spot.

Timing: what the research supports

Pre-exercise dosing has the strongest evidence. Tipton et al. (2001) demonstrated in American Journal of Physiology that EAAs consumed immediately before resistance exercise produced significantly greater net muscle protein synthesis than the same dose consumed immediately after — primarily because amino acids were already circulating when exercise-induced blood flow increased delivery to working muscles. Total net phenylalanine uptake across the leg was 209 ± 42 mg during PRE versus 81 ± 19 mg during POST.

Post-exercise dosing is still effective. MPS remains elevated for 24–48 hours after resistance exercise, as shown by Burd et al. (2011), so amino acids consumed in the hours following training are well-utilized.

Between-meal dosing is underappreciated. Paddon-Jones et al. (2004) showed in American Journal of Physiology that EAAs consumed as a bolus stimulated MPS additively in both young and elderly subjects — boosting synthesis on top of whatever meals provided.

What the evidence doesn’t support: continuous sipping. Bohé et al. (2001) found that MPS peaks within about 2 hours of sustained amino acid elevation and returns to baseline despite continued availability. Pulsed, discrete doses outperform constant low-level intake.

Frequency: how many doses per day

Given the muscle full effect and the refractory period, the research supports 3–4 discrete EAA-rich events per day as optimal for maximizing 24-hour protein synthesis. Space them 3–4 hours apart. Each spike triggers a new round of MPS.

Adjustments by population

Athletes and heavy training: Higher training volumes increase amino acid oxidation. Consider 12–15g EAAs per serving and an additional daily serving on heavy training days.

Older adults (50+): Aim for the full 12–15g EAAs per serving. Katsanos et al. (2005) showed diminished muscle protein accretion with small EAA boluses in elderly subjects, suggesting a higher threshold is needed.

Caloric restriction / fat loss: Maintain 10–12g per serving. Pre-exercise dosing becomes particularly important to shift the balance from catabolic to anabolic during training.

Recovery from injury or surgery: Doses at the higher end (12–15g, 2–3x daily) are reasonable during enforced rest. Paddon-Jones et al. (2004) demonstrated EAAs can stimulate MPS even without exercise.

Common dosing mistakes

Underdosing per serving. 3–5g of EAAs won’t maximally stimulate MPS. If you’re going to supplement, take enough to matter.

Taking EAAs with a large protein meal. Adding EAAs on top of a 40g protein meal is largely redundant. Save your supplement dose for between meals or pre-workout.

Constant sipping. Mixing EAAs into a water bottle and sipping over hours maintains low-grade elevation that triggers the muscle full effect without ever producing a robust MPS spike. Drink it in one sitting.

Summary table

References

1. Cuthbertson D, Smith K, Babraj J, et al. Anabolic signaling deficits underlie amino acid resistance of wasting, aging muscle. FASEB J. 2005;19(3):422-424. PubMed
2. Moore DR, Robinson MJ, Fry JL, et al. Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. Am J Clin Nutr. 2009;89(1):161-168. PubMed
3. Atherton PJ, Etheridge T, Watt PW, et al. Muscle full effect after oral protein: time-dependent concordance and discordance between human muscle protein synthesis and mTORC1 signaling. Am J Clin Nutr. 2010;92(5):1080-1088. PubMed
4. Bohé J, Low JF, Wolfe RR, Rennie MJ. Latency and duration of stimulation of human muscle protein synthesis during continuous infusion of amino acids. J Physiol. 2001;532(Pt 2):575-579. PubMed
5. Tipton KD, Rasmussen BB, Miller SL, et al. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise. Am J Physiol Endocrinol Metab. 2001;281(2):E197-E206. PubMed
6. Paddon-Jones D, Sheffield-Moore M, Zhang XJ, et al. Amino acid ingestion improves muscle protein synthesis in the young and elderly. Am J Physiol Endocrinol Metab. 2004;286(3):E321-E328. PubMed
7. Burd NA, West DW, Moore DR, et al. Enhanced amino acid sensitivity of myofibrillar protein synthesis persists for up to 24 h after resistance exercise in young men. J Nutr. 2011;141(4):568-573. PubMed
8. Katsanos CS, Kobayashi H, Sheffield-Moore M, et al. Aging is associated with diminished accretion of muscle proteins after the ingestion of a small bolus of essential amino acids. Am J Clin Nutr. 2005;82(5):1065-1073. PubMed