Branched-chain amino acids (bcaa)
Branched-chain amino acids (bcaa)


Branched-chain amino acids (BCAAs) are essential nutrients including leucine, isoleucine, and valine. They're found in meat, dairy, and legumes.

BCAAs stimulate the building of protein in muscle and possibly reduce muscle breakdown. The "Branched-chain" refers to the chemical structure of these amino acids.

BCAAs are used for reduced brain function in people with advanced liver disease and for a movement disorder often caused by antipsychotic drugs. They are also commonly used to improve athletic performance, prevent fatigue, reduce muscle breakdown, and other purposes, but there isn't enough reliable information to support these other uses.
When taken by mouth: BCAAs are likely safe when used in doses of 12 grams daily for up to 2 years. It might cause some side effects, such as fatigue and loss of coordination. BCAAs should be used cautiously before or during activities that require motor coordination, such as driving. BCAAs might also cause stomach problems, including nausea, diarrhea, and bloating.

Special Precautions & Warnings:

Pregnancy and breast-feeding: There isn't enough reliable information to know if BCAA supplements are safe to use when pregnant or breast feeding. Stay on the safe side and stick to food amounts.

Children: BCAAs are likely safe when taken in food amounts. They are possibly safe when taken by children in larger doses for up to 6 months.

Amyotrophic lateral sclerosis (ALS, Lou Gehrig disease): BCAA supplements have been linked with lung failure and higher death rates when used in patients with ALS. If you have ALS, do not use BCAA supplements until more is known.

Branched-chain ketoaciduria: People with this condition can experience seizures and severe delays in mental and physical development when BCAAs are consumed. Don't use BCAAs if you have this condition.

Diabetes: BCAA supplements might affect blood sugar levels. Watch for signs of low or high blood sugar and monitor your blood sugar carefully if you have diabetes and take BCAA supplements.

Surgery: BCAA supplements might affect blood sugar levels, and this might interfere with blood sugar control during and after surgery. Stop using BCAA supplements at least 2 weeks before a scheduled surgery.


NatMed Pro rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
Likely effective Effectiveness definitions
Possibly effective Effectiveness definitions
  • Reduced brain function in people with advanced liver disease (hepatic encephalopathy). Taking BCAAs by mouth seems to improve liver function in people with poor brain function caused by liver disease.
  • A movement disorder often caused by antipsychotic drugs (tardive dyskinesia). Taking BCAAs by mouth seems to reduce symptoms of this condition in adults and children taking antipsychotic drugs.
Likely ineffective Effectiveness definitions
  • Lou Gehrig disease (amyotrophic lateral sclerosis or ALS). Taking BCAAs by mouth is not beneficial in people with ALS. In fact, it might make lung function worse and increase the chance of death in people with this condition.
There is interest in using BCAAs for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.
Possibly ineffective Effectiveness definitions
  • Liver cancer. Taking up to 50 grams of BCAAs by mouth twice daily for up to one year does not seem to improve outcomes in people with liver cancer who have had surgery.
Insufficient evidence Effectiveness definitions

Dosing & administration

BCAAs are important nutrients found in protein sources such as meat, dairy, and legumes. It's estimated that adults should consume about 68 mg/kg daily (leucine 34 mg/kg, isoleucine 15 mg/kg, valine 19 mg/kg). But other estimates suggest that adults might actually need 144 mg/kg daily. Recommended amounts for children depend on age. Speak with a healthcare provider to find out what dose might be best for a specific condition.

Interactions with pharmaceuticals


Interaction Rating=Major Do not take this combination.

BCAA supplements can decrease how much levodopa is absorbed by the intestines or brain. By decreasing levodopa absorption, BCAAs can decrease the effects of levodopa.

Medications for diabetes (Antidiabetes drugs)

Interaction Rating=Moderate Be cautious with this combination.

BCAA supplements might lower blood sugar levels. Taking BCAAs along with diabetes medications might cause blood sugar to drop too low. Monitor your blood sugar closely.

Interactions with herbs & supplements

There are no known interactions with herbs and supplements.

Interactions with foods

There are no known interactions with foods.
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