Essential amino acid
Isoleucine
One third of the BCAA trio. Glucose uptake and muscle fuel.
20 mg/kg/dayAbout 1.40 g a day at 70 kg
What it builds
Isoleucine is one of the three branched-chain amino acids, alongside leucine and valine. Unusually, the branched-chain three are oxidised directly in muscle rather than being processed by the liver first, which is why they are burned as fuel during long efforts. Isoleucine also stimulates glucose uptake into cells, and contributes to haemoglobin.
Where isoleucine actually comes from
Eggs, poultry and fish lead among animal foods; soy leads among plants.
Ranked by a realistic portion rather than per 100 g, because nobody eats 100 g of pumpkin seeds. Figures are digestibility-adjusted, so these are the amounts the app credits you with, not the amounts printed on the packet. Computed live from the 72 foods in the AminoLens recommender pool.
All foods
Every food in the pool, animal and plant.
| Food | Portion | Per portion |
|---|---|---|
| Chicken breast | 120 g breast | 1.87 g |
| Lamb leg | 120 g | 1.55 g |
| Beef (eye of round) | 120 g | 1.54 g |
| Pork tenderloin | 120 g | 1.47 g |
| Chicken thigh | 120 g | 1.34 g |
| Haddock | 120 g fillet | 1.22 g |
Plant-based only
Vegan foods only. The list most people actually need.
| Food | Portion | Per portion |
|---|---|---|
| Soybeans | 120 g cooked | 881 mg |
| Tempeh | 100 g | 801 mg |
| Extra-firm tofu | 150 g | 669 mg |
| Firm tofu | 150 g (half a block) | 606 mg |
| White beans | 150 g cooked | 528 mg |
| Pinto beans | 150 g cooked | 524 mg |
Signs you might be short
Rarely the limiting line on its own. Isoleucine tends to move with total protein rather than independently of it.
Pairs well with
Soy is the standout plant source. Beyond that, the branched-chain three travel together, so anything that fixes leucine fixes isoleucine.
See your isoleucine coverage
Photograph a meal and watch where the protein actually goes.
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