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Branched-chain amino acids (BCAAs)

Leucine-rich essential amino acid blend with meta-analysis signal for reduced exercise-induced muscle damage and modest sarcopenia benefit in older adults.

Why

Branched-chain amino acids (BCAAs: leucine, isoleucine, valine) make up about 35% of essential amino acids in muscle. Meta-analyses report modest reductions in delayed-onset muscle soreness and creatine kinase elevation after eccentric exercise, particularly at higher leucine content. In sarcopenia contexts, BCAA (and leucine specifically) added to protein intake supports muscle protein synthesis in older adults with low intake. Effect is smaller than complete protein for hypertrophy; BCAAs are an adjunct, not a substitute.

How it works

Leucine activates the mTORC1 signalling pathway in skeletal muscle, triggering ribosomal protein synthesis. Isoleucine modulates glucose uptake. Valine contributes substrate. BCAAs are oxidised in muscle (unlike most amino acids), making them a substrate for energy production during prolonged exercise.

Expected onset · Recovery effects acute (within 24–48 hr); sarcopenia effects over 8–12 weeks

How to take

Dosage

Exercise recovery: 5–10 g/day, often divided around training. Sarcopenia adjunct: 3–6 g leucine/day. Ratio 2:1:1 leucine:isoleucine:valine is the trial-typical form.

Timing

Pre-, intra-, or post-workout; or split across the day

On the label

2:1:1 leucine:isoleucine:valine ratio is standard. Higher leucine ratios (4:1:1, 8:1:1) for hypertrophy use. Powder is more cost-effective than capsules at therapeutic doses.

Ideal for

Recreational athletes with intense training schedules; older adults with low protein intake seeking muscle-preservation adjunct; people with hepatic encephalopathy (clinical indication, specialist supervision).

Safety

Generally very well tolerated. Bitter taste; flavoured products help. Theoretical concern in advanced ALS (high BCAA may worsen motor neuron function); avoid in maple syrup urine disease (BCAA metabolism disorder). Hepatic encephalopathy use is clinical-context only and supervised. Pregnancy and breastfeeding: dietary intake fine; supplement use limited data.

Evidence

At a glance

Fouré 2017 Nutrients systematic review (11 RCTs): BCAA supplementation around exercise reduced delayed-onset muscle soreness and creatine kinase elevation in most trials. Komar 2015 meta-analysis in older adults: leucine-rich protein supplementation modestly increased lean body mass and grip strength vs control. Effect is real but supplementary; complete protein intake matters more.

Where to get it

Shop Branched-chain amino acids (BCAAs) on Amazon

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