BCAAs / EAAs
Branched-chain amino acids (leucine, isoleucine, valine) — the muscle-building amino acids. Mostly redundant if you eat enough complete protein; useful in specific cases.
Limited evidence for additional muscle gains in protein-sufficient lifters. Moderate evidence for fasted-training support, intra-workout fatigue reduction (modest), and use in vegan / low-protein contexts. EAAs outperform BCAAs at the same dose.
BCAAs are leucine, isoleucine, and valine — the three branched-chain amino acids your body can't make. Leucine in particular triggers muscle protein synthesis via mTOR. The marketing case: drink BCAAs around workouts to build muscle. The reality: if you eat enough complete protein (1.6–2.2 g/kg body weight), additional BCAAs don't measurably build more muscle — you already have plenty. EAAs (essential amino acids) — which include BCAAs plus the other six — are more effective when used as a complete protein substitute (fasted training, between meals on a low-protein day, vegan athletes). For most well-fed lifters, BCAAs are an expensive way to get something you already have.
- Form
- BCAAs in 2:1:1 ratio (leucine:isoleucine:valine). EAAs with all nine essential amino acids — more useful.
- Dose
- BCAAs: 5–20 g pre / intra-workout. EAAs: 10–15 g.
- Timing
- Around workouts, especially fasted training. Sip during prolonged sessions.
- Schedule
- On training days, when needed. Not foundational.
- Side effects
- Generally well-tolerated. Mild GI upset, weight gain (calories).
- Interactions
- Generally clean. May modestly affect serotonin / tryptophan transport.
- Contraindications
- Maple syrup urine disease (rare genetic BCAA disorder). ALS (theoretical — BCAAs investigated as both helpful and possibly harmful). Pregnancy (limited high-dose data).
- Lab markers
- Body composition, performance tracking.
- Food sources
- Whey protein, eggs, beef, chicken, fish, dairy, legumes all contain BCAAs and EAAs at high levels. A 25–30 g serving of whey delivers more BCAAs than a typical scoop of BCAA powder.
Pairs with
Creatine, beta-alanine, electrolytes (training stack). Whole protein meals (the actual driver).
Where to buy
Prices are checked periodically and drift — Amazon’s is the live one. We take no commission on these links.
within Amino acids & derivatives