Inhibition of nitric oxide is a sad side effect that might cause cardiovascular dysfunction.
"These results suggest that L-leucine inhibits NO production by endothelial cells"
http://www.fasebj.or...bstracts/1127.3
"These studies demonstrate that glucosamine is a novel inhibitor of inducible NO synthesis via inhibition of iNOS protein expression"
http://www.ncbi.nlm....pubmed/11112445
Supplementation for the catabolism of leukine might be a good idea.
"Such means may include dietary supplementation with α-ketoglutarate to enhance the catabolism of L-leucine"
http://www.ncbi.nlm....pubmed/25552397