L-isoleucine explained: what it is and food sources
The NIH says isoleucine is one of the nine essential amino acids and that muscles can use it and the other two BCAAs for energy during exercise. It occurs with other BCAAs in meat, fish, and milk. One product we reviewed lists L-isoleucine, and none prints its individual amount.
- What it is
- Amino acid
- In the products we reviewed
- 1, its label does not print the amount
What L-isoleucine is
- Isoleucine occurs with other BCAAs in animal foods such as meat, fish, and milk.2
- Isoleucine is one of the nine essential amino acids.1
- Isoleucine, leucine, and valine are collectively called BCAAs.2
- Muscles can use isoleucine and the other two BCAAs for energy during exercise.2
Foods that have it2
- meat
- fish
- milk
How much L-isoleucine each product gives
Amount not printed: the dashed line shows the most it can be, the whole blend
Before you take it
Ask a doctor first
- Taking up to an additional 20 grams a day of combined BCAAs in supplements seems safe.2
These statements have not been evaluated by the FDA. A supplement is not a medicine.
The product we reviewed that lists L-isoleucine
| Product | Form and serving | L-isoleucine per serving | Our score | Price a bottle | Buy |
|---|---|---|---|---|---|
 NeuroQuiet#3 in hearing support | Oral spray6 sprays | Not printedIn the 1000 ng HGA Blend | 9.7 | $49 | Check price |
Questions people ask
Is isoleucine an essential amino acid?
Yes, the NIH says isoleucine is one of the nine essential amino acids.
Is isoleucine a branched-chain amino acid?
Yes, the NIH says isoleucine, leucine, and valine are collectively called BCAAs.
What foods contain isoleucine?
Meat, fish, and milk contain isoleucine. It occurs alongside other BCAAs in these animal foods.
What does isoleucine do in the body?
Muscles can use isoleucine and the other two BCAAs for energy during exercise, according to the NIH.
What should I check before taking an isoleucine supplement?
Check how much isoleucine and other BCAAs the supplement contains. Taking up to an additional 20 grams a day of combined BCAAs in supplements seems safe, but that figure is for combined BCAAs, not isoleucine alone. Ask a clinician before starting.
Which products we reviewed contain L-isoleucine?
NeuroQuiet is the only product we reviewed that lists L-isoleucine. It is an oral spray with a serving of 6 sprays. L-isoleucine is inside the 1000 ng HGA Blend, with no individual amount printed.
Sources
The products, amounts and prices come from each product's label and checkout, as its review shows them. AI drafts our pages from listed sources, figures are checked against them, and we have not tried the products.
- 1NIH Office of Dietary Supplements, ExerciseAndAthleticPerformance HealthProfessionalods.od.nih.gov/factsheetschecked
- 2NIH Office of Dietary Supplements, ExerciseAndAthleticPerformance Consumerods.od.nih.gov/factsheetschecked