Can You Take L-Leucine and L-Valine Together?

May affect absorption

The short answer

L-Leucine and L-Valine are both BCAAs sharing the same intestinal and BBB transporters. When taken individually, leucine's higher affinity for LAT1 may reduce valine transport to the brain.

How to arrange timing

When supplementing individual BCAAs, separate L-Leucine and L-Valine by at least 1 hour for optimal absorption.

Reference

Reference noted for this combination: Fernstrom JD. Branched-chain amino acids and brain function. J Nutr. 2005;135(6 Suppl):1539S-1546S.

Important context

Whether supplements suit you together also depends on dose, product formulation, health conditions, and medication use. Ask a doctor or pharmacist first if you take medication, are pregnant or breastfeeding, or have a chronic condition.