diff --git a/zsh-nvm.plugin.zsh b/zsh-nvm.plugin.zsh
index a99d5ce..49e0437 100644
--- a/zsh-nvm.plugin.zsh
+++ b/zsh-nvm.plugin.zsh
@@ -62,7 +62,7 @@ nvm_update() {
 _zsh_nvm_upgrade() {
 
   # Use default upgrade if it's built in
-  if _zsh_nvm_nvm --help | grep -q 'nvm upgrade'; then
+  if [[ "$(_zsh_nvm_nvm help | grep 'nvm upgrade')" ]]; then
     _zsh_nvm_nvm upgrade
     return
   fi